The addition of electronics, computers, and software to interferometry has provided tremendous improvements in the measurement of surface shape and roughness. This talk will describe three such improvements; use of computer generated holograms for testing aspheric surfaces, techniques for performing interferometric measurements more accurate than the reference surface, and two single-shot phase-shifting interferometric techniques for reducing the sensitivity of an optical test to vibration and measuring dynamically changing surface shapes.

Reaction Bonded (RB) SiC mirrors due to their excellent specific stiffness and thermal properties have been widely used in space telescopes. However, polishing large SiC aspherical mirrors is difficult compared to other materials such as fused silica or Zerodu. In addition, surface roughness of the polished SiC mirrors is limited by the defects of the materials and needs to be improved by means of surface coating technique. This paper introduces the current progress of large SiC aspherical mirrors manufacturing and testing in CIOMP. In particular, the procedures of making large off-axis aspherical mirrors were discussed in detail. A proprietary computer controlled optical surfacing (CCOS) technique was utilized to grind and polish the mirrors and the computer aided null test was used to measure the surface figure. As results, a 600mm class off-axis SiC aspherical mirrors was demonstrated with figure error less than 13nm rms.

Optical metrology requiring a large dynamic range places several requirements on the design and operation on the instrument. In addition to being able to detect the part or wavefront shape to the required range and precision, the measurements must also be calibrated to remove the induced errors associated with operation in a non-null fashion. This paper demonstrates the need for this calibration, and presents the results of a system calibration of a non-null interferometric measurement.

The Multi-Spectral Camera (MCS) is the electro-optical imaging isntrument for high-resolution observation of the Earth with push broom scanning in the space. The MSC uses compact and light weighted optical design to tkae image with high MTF (modulation transfer function) performance. The Ritchey-Chretien with focal correct lens is selected to implement enough performance in the wide swath width. The focal plane has one panchromatic (PAN) and four multi-spectral (MS) CCD (charge coupled device) for the imaging of visible and near-infrared wavelength. The PAN and MS have their own focus correct lens to correct field aberration and also to make proper effective focal length. Here we present the optical design and analysis of the MSC.

In the introduction it is presented a brief history of the evolution of physics and its professional organizations in Latin America, how optics is introduced in these countries, the development of the optical community and of its meetings. The evolution of the optical meetings in which Latin Americans take part and the participation of each country are described. A clear increase in the number of communications presented in these meetings is observed. It is shown that Latin American people contribute many more communications than Iberian people to these kinds of meetings. A study is made of the proportion of co-worked communications presented at these meetings showing the variations in the quantity of these collaborative works from Latin Americans, from Latin Americans and people from the Iberian Peninsula and from people outsides these regions. A study is also presented about the amount of papers published between 1974 and 2004 by people working in the Latin American countries and also in Spain and Portugal, showing the participation of each country. In particular it is shown that Latin Americans publish only a little more than Iberian people. Finally, answers are given to some questions about the present situation of optical research in Latin America.

Many practical applications of x-rays lie in the important for the society fields of medical imaging, custom, transport inspection and security. Scientific applications besides of fundamental research include material sciences, biomicroscopy, and protein crystallography. Two types of x-ray sources dominate now: conventional tubes and electron accelerators equipped with insertion devices. The first are relatively cheap, robust, and compact but have low brightness and poorly controlled photon spectrum. The second generate low divergent beams with orders of magnitude higher brightness and well-controlled and tunable spectrum, but are very expensive and large in scale. So accelerator based x-ray sources are mainly still used for scientific applications and x-ray tubes - in commercial equipment. The latter motivated by the importance for the society made an impressive progress during last decades mostly due to the fast developments of radiation detectors, computers and software used for image acquisition and processing. At the same time many important problems cannot be solved without radical improvement of the parameters of the x-ray beam that in commercial devices is still provided by conventional x-ray tubes. Therefore there is a quest now for a compact and relatively cheap source to generate x-ray beam with parameters and controllability approaching synchrotron radiation. Rapid developments of lasers and particle accelerators resulted in implementation of laser plasma x-ray sources and free electron lasers for various experiments requiring high intensity, shrt duration and monochromatic x-ray radiation. Further progress towards practical application is expected from the combination of laser and particle accelerator in a single unit for efficient x-ray generation.

The objective of this paper was to generate Sidel polynomials using a LCD in a Fourier processor. Our proposal was to use this LCD, due to the fact that it is a small device that does not consume too much energy, with several active elements, and we verified the speed with which it is possible to work with optical processing by changing the images on the screen. Since this system is easy to construct, stable and accessible, we want to use it in the future as a corrector system, due to the fact that it can evaluate the system using a program and with the LCD to try to correct the aberrations that it has.

Laser particle spectrometry is one of the leading measurement technologies engaged in environmental monitoring, measuring the aerosol contamination of the air inside and outside of urban regions. It has a number of benefits against other methods - e.g. the possibility of real time, in situ measurement with high time resolution. These features make the light scattering based measurement methods superior to others in a mobile environmental laboratory. Our previously developed instruments are based on laser light scattering collected from different angular regions (90°, forward and backward directions) and a special illumination system increase the sensitivity and the resolution of the sizing. A collection of the developed optical instruments and other devices based on different methods were installed into a mobile environmental laboratory for monitoring atmospheric aerosols, which allows the comparison of the results obtained from different measurement methods. This laboratory has been used in 3 measurement campaigns where measurements were performed in 6 different locations.

We propose a sinusoidal wavelength scanning interferometer for measuring thickness and surfaces profiles with a thin film. An acousto-optic tunable filter (AOTF) is used to produce sinusoidally wavelength-scanned light from a superluminescent laser diode (SLD) with a wide spectral bandwidth of 46nm. The interference signal contains an amplitude Z_b of a time-varying phase and a constant phase α. Two measured values of OPD, which are denoted by L_z and L_α, are obtained from Z_b and α. By combining L_z and L_α, an OPD longer than a wavelength is measured with an error less than a few nanometers. When the object has two reflective surfaces, the detected interference signal contains two interference signals which are caused by the front and rear surfaces. In this case we must determine the values of Z_b1, Z_b2, α₁, and α₂, where suffixes of 1 and 2 are corresponding to the front and rear surfaces, respectively. We define an error function that is the difference between the detected signal and the theoretical signal, and reduce the value of the error function with the multidimensional nonlinear least-squares algorithm to search the values of Z_b1, Z_b2, α₁, and α₂. Experimental results show that the thickness and surfaces profiles of a silica glass plate of 20μm-thickness are measured with error less than 1.5nm.

We proposed sensitive measurement of water content in dry material using low-frequency THz-TDS method. Simultaneous use of bowtie-type photoconductive antennas as a THz emitter and a THz detector achieves specific sensitivity in sub-THz region of ~0.3 THz, in which THz absorption of water is considerably decreased. Effectiveness of the proposed method is demonstrated through water content measurement in instant coffee powder in a glass bottle. The proposed system will be a powerful tool for extract quality control of water content in dry foods.

We have constructed a Fourier-transform phase-modulation fluorometer (FT-PMF) by which a fluorescence decay waveform can be obtained. In the FT-PMF, the modulation frequency of the excitation light source is swept continuously from a direct current (dc) to a high frequency f_max with a time duration T. The resultant fluorescence signal waveform is Fourier-transformed to obtain its amplitude and phase spectra. The ratio of the amplitude spectrum and the difference of the phase spectrum over those of the reference spectra that are obtained from a non-fluorescent material are calculated, respectively, and the pair of both spectral data is inverse-Fourier-transformed again to obtain the fluorescence decay waveform. The light source used was an ultraviolet light emitting- diode (UV LED) whose typical operating condition was f_max = 100 MHz and T = 10 μs. To demonstrate the performance of the FT-PMF, we carried out (1) measurement of a fluorescent decay waveform of YAG materials packed in a white LED, and (2) determination of fluorescence lifetime of 10 ppm quinine sulfate in 0.1N H₂SO₄.

The experimental and theoretical results, used for an adjustable quarter wave plate development, are proposed for the light wavelength measurement. To prove that idea propagation of coherent and incoherent light through an adjustable quarter wave plate with different properties was considered. The dependence of the adjustment angle on the light wavelength was obtained for different parameters of single retarder. All calculations were performed for mica retarders. It was shown principal possibility of light wavelength shift detection with accuracy 0.1 nm within wavelength range 3 nm for coherent light. Experimental investigation was performed for an adjustable quarter wave plate made of two mica plates of the same retardation. The qualitative coincidence between experimental and theoretical results has demonstrated.

A new method of determination of only an ellipticity of a state of polarization of a coherent radiation is proposed. The method is based on a spatial separation of a wave with the arbitrary ellipticity of a state of polarization into two waves with mutually orthogonal circular states of polarization. To part elliptically polarized light into two waves with orthogonal circular polarizations, the optical Magnus effect in a multimode optic fiber and a phase conjugator were used. The main advantage of a method is dealing with light intensities of almost the same values in the case of weekly elliptically polarized light. It was shown experimentally that precision of measuring increases noticeably for weakly elliptically polarized light. The simple device for the determination of the polarized light ellipticity is proposed.

In glass casting or shaping processes, some times wavy and distortion defects are developed in glass sheets. Specifying the locations of these defects and measuring the deflections they cause are significant parameters in many applications. There are several techniques for observing and measuring these defects, but the technique we introduce in this work is more simple and flexible and can be easy installed in production line for quality controlling purposes. The presented deflectometer functions in the following way. The imaging system of the device forms an image of large-scale low frequency linear periodical pattern painted on a vertical plane on a transmission grating. The distance between the object grating (painted pattern) and the second grating is so that the frequencies of the image grating and the second (probe) grating are practically the same. There is a small angle between the lines of the latter gratings to form moire fringes. A CCD camera transfers the moire fringes to a PC. By applying phase shifting technique, which is realized by shifting the probe grating in definite steps in its plane in a direction perpendicular to its lines, the phase distribution due to imprecations in optical system and gratings, are specified, At this stage the defected sheet glass is installed between the object grating and the imaging system and the distorted moire pattern is processed as described before. The difference between two-phase distributions is the phase distribution caused by the defects in the glass, which can be easily converted into the required ray deflections. All the processes are carried out automatically in a time less than 30 seconds and the accuracy of the measurement is of the order of 20 arc seconds.

Interferometric displacement sensor based on a two-wavelength interferometry is proposed and demonstrated. A combination of time-shared two-wavelength laser diode and sinusoidal phase-modulating interferometry enables us to realize accurate and wide-range displacement measurement with a simple optical setup.

The mathematical model for measuring moving objects (including fluid body, rolled steel materials in the steel works, turbulent flow, vibration body, etc.) velocity or speed by non-contact method is established using light-wave Doppler effect in this paper. In terms of concrete conditions of different optical circuits, and with the correlated conditions substituted, it is easy to obtain the measurement velocity formulas related to optical circuits. An optical circuit layout of difference Doppler effect measuring velocity is suggested in this paper. The fine beam of light emitted by laser is divided into parallel two beam by spectroscope and mirror They are focused on the object point p by a condenser lens respectively. The object point p become a diffuse source. It scatter rays to every aspect. Some rays scattered by the diffuse source p are collected by a lens. Photoelectric detecter receive the lights collected by the lens. This optical circuit layout can realize the double frequency of difference frequency signals in a novel way.

This work briefly reviews recent progress in interferometric monitoring of spin and of dip coating, from a unified point of view, and its application for contactless viscometry of liquid films. Considering the associated models and measurement uncertainties, the method was validated for both coating processes with oil standards of known viscosities and constant refractive indices. Limitations and perspectives for application of the laser viscometer to liquid films with a varying refractive index are also discussed.

The beam emitted by a laser diode chip is elliptical and astigmatic. Various methods have been proposed and applied to remove the astigmatism and to produce a circular Gaussian beam. In this paper we will further propose the use of the laser diode beam correction optics in an external cavity laser. The light produced by the external cavity laser is not only circular, Gaussian, and non-astigmatic, but its coherence length is also significantly enhanced.

In this paper, we present the working principle and the preliminary results of a novel vibration sensor based on wavefront-splitting interferometry. The interference signal is formed by superposing the radiations within a compact sensor space at which the wavefront is split and reflected by the sample surface. The performance of sensor is determined by the geometrical dimensions, the polarization of the incident light and the optical properties of the sample surface. Due to the grazing incidence of the detecting light, the interference signal is strong and obvious regardless of the material of the sample surface. Therefore, this fiber-optic sensor is more sensitive than the other displacement and vibration sensors, especially when applied for the optically low-reflective samples. The experiments using the OHP transparency and the metal structures demonstrate the static and dynamic measurements of the fiber-optic sensor.

In recent years, FTIR has been found its wider application in analysis processes of pharmaceutical solids. This is, in part, thanks to the development of powerful multivariate quantitative techniques, such as partial least-squares (PLS) modeling software and the emergence of some new reflectance sampling techniques which allow direct measurement of the IR spectrum of solids in their native states. Horizontal Attenuated Total Reflectance (HATR) is a quite popular sampling technique in recent years. In this work, the feasibility of the Horizontal Attenuated Total Reflectance Infrared Spectroscopy (HATR-FTIR) to the quantitative and quantitative analysis of nimodipine tablets is investigated. Quantitative analysis of nimodipine is carried out by using a classical least-squares for areas procedure. Obtained from validated samples of nimodipine, quantitative results demonstrate clearly the strong potential of HATR-FTIR technique through using quantitative analysis of nimodipine content of pharmaceutical tablets.

In this paper, a portable diagnostic instrument was designed and tested, which can measure the normalized difference vegetation index (NDVI) and structure insensitive pigment index (SIPI) of crop canopy in field. The instrument have a valid survey area of 1 m*1 m when the height between instrument and the ground was fixed to 1.3 meter The crop growth condition can be assessed based on their NDVI and SIPI values, so it will be very important for crop management to get these values. The instrument uses sunlight as its light source. There are six special different photoelectrical detectors within red, blue and near infrared bands, which are used for detecting incidence sunlight and reflex light from the canopy of crop. This optical instrument includes photoelectric detector module, signal process and A/D convert module, the data storing and transmission module and human-machine interface module. The detector is the core of the instrument which measures the spectrums at special bands. The microprocessor calculates the NDVI and SIPI value based on the A/D value. And the value can be displayed on the instrument's LCD, stored in the flash memory of instrument and can also be uploaded to PC through the PC's RS232 serial interface. The prototype was tested in the crop field at different view directions. This paper also provided the method of calibration, the results showed that the average measurement error to SIPI value of instrument was 5.25% and the average measurement error to NDVI value in vegetation-covered region is 6.40%. It reveals the on-site and non-sampling mode of crop growth monitoring by fixed on the agricultural machine traveling in the field.

A kind of Micro-displacement measuring instrument using double interference cavities is designed. It is based on F-P interference wave length One of interference cavities is reference cavity, the other is measuring cavity. One reflect surface of reference cavity is installed with piezoelectric ceramics, One reflect surface of measuring cavity is erected with an object to be measured. When the central wavelengths in reference Fabry-Perot interference and in measuring Fabry-Perot interference are overlapped, there are the maximum light signal outputs. Based on the relationship between the transmission spectrum central wave length and its interference cavity length, this measuring instrument can be used to realize the real time measurement of Nano-grade micro-displacement. Using simi- conductor laser as the light resource can obtain the required wavelength values and its variation scopes. It can be seen from the measured results that the measured error is not over 1.5nm. Such a precision can satisfy the precision requirements as in the fields of precision mechanical processing, photoelectronic processing and Nano- grade measuring technology.

It is easy to extract a signal proportional to a phase fluctuation from a sinusoidally phase-modulated interference signal. This fluctuation is caused by mechanical vibration or air turbulence. In a sinusoidal phase-modulating interferometer using a laser diode (LD) the phase fluctuation is reduced by changing the injection current of the LD with a feedback control system. This control is very useful to a Fizeau type interferometer for surface profile measurement of a large size object. IC wafers of 100 mm diameter are measured with an interferometer insensitive to mechanical vibration and air turbulence. The phase fluctuation with nearly constant amplitude which corresponds to 30nm in surface height is reduced by about 10%. However the reduction in the phase fluctuation is not performed well for an instantaneous and large phase fluctuation. In order to be insensitive to all kinds of phase fluctuations the feedback signal is always observed, so that the interference signal is captured when the amplitude of the feedback signal is less than a specified level during the capturing time of 0.53 s. Thus surface profiles of the IC wafers can be measured with a high repeatability of a few nm even when any kind of vibration exists.

Wavelength tuning interferometry can distinguish interference signals from different surfaces in frequency space. The optical thickness variation of each layer of a multiple-surface object was measured by a new tunable phase measuring algorithm which can efficiently compensate for the frequency detuning of the interference signals. A two-layer object consisting of Lithium Niobate (LNB) wafer on the supporting glass parallel was measured by the new tunable algorithm in a Fizeau interferometer. Experimental results show that the optical thickness variation of the top wafer was measured with an error of λPV over a 70 mm diameter aperture.

This work studies rough surfaces that undergo small random morphological changes. In the present paper, rough reflective surfaces are dealt with. Its roughness is larger than the wavelength of the He-Ne laser beam used to illuminate it. Speckle correlation of the scattered light is applied to study changes in the roughness. A theoretical model, which describes speckle correlation as a decreasing quadratic exponential function of roughness changes and was presented in a previous paper, is used. New experimental results from rough reflective surfaces in which the changes are simulated through immersion of the samples in liquids with different refraction indices are presented. Good agreement between the theoretical and experimental results is found.

A method for measuring diameters of metal cylinders is proposed. In this method a sinusoidally vibrating interference pattern (SVIP) of 100μm-period is used to generate an exact spatial scale along x-axis. Detection of the amplitude and the phase of the SVIP are carried out easily and exactly with sinusoidal phase-modulating interferometry. First, phase values of the SVIP on the pixels of the CCD image sensor are measured as the exact scale along the x-axis. Next, an image of the end-points of the cylinder surface is formed by extracting lights from the end-points of the cylinder. The phase of the SVIP on the end-point of the cylinder appears at a position where the amplitude of the image has maximum value along the x-axis. The x-coordinate of the end-point of the metal cylinder is calculated from the phase value of the end-point and the exact scale. The diameter is obtained from the x-coordinates of the two end-points. Metal cylinders of 9mm and 8mm-diameters are measured with an error of about ±2μm.

A television camera system, which automatically picks out exclusive images of the oil at real time, is described. This system essentially consists of two optical band pass filters (BPFs), two CCD cameras and image processing software. Due to the multiple-beam interference resulted from the oil film, there is a marked difference of intensity between light reflected from the surface of the sea and that from oil film. By obtaining these different images, the place with oil can be distinguished. Emphasis of our work is to compensate the effect of dispersion of sunlight intensity and CCD's quantum efficiency on oil film detection probability. Laboratory experiments using static glass coated with Al₂O₃ film have been conducted. The experimental results showed that sensing probability is dependent on the sample thickness, and greatly on the incident angle. This result is agreed quite well with the simulation done our coauthors in earlier work.

In this paper, we present a new and practical method for achieving real-time wavefront measurement, dramatically increasing the resolution, dynamic range of Shack-Hartmann wavefront sensor and improving the wavefront reconstruction quality. In proposal method, a liquid crystal display panel (LCD) for the generation of an array of Fresnel microlenses is used instead of the static microlens array of the conventional Shack-Hartmann type sensor An off-axis holographic microlens array is designed instead of the normal microlens array to increase the effective array and then the dynamic range. The focus properties of the off-axis lens are studied.

Vehicle navigation is the corn element of Intelligent Transport System. The integrated system of "Beidou" Double-star/DR is studied in this paper according to the present state of vehicle navigation in our country. "Beidou" Double-star navigation position system is one regional satellite position system built up by our country, which can provide rapidly not only highly precision position and brevity telegram service. However, when the vehicles go around the tall buildings, high mountain area, wayside trees and in the tunnels, all signal may not be received. If the satellite navigation position system is used only, the precision will be reduced. Therefore, this paper proposes a nonlinear self-adaptive Kalman filter model and its algorithm for a Double-star/DR integrated navigation system in land vehicles, and verifies effectively the algorithm and scheme through the means of simulation. Next, this paper introduces map match approach. The roads are segmented and character information is brought out. Then, proper search rules and map match algorithm are adopted. According to the current vehicle position information that Double-Star/DR system provides, the nearest road can be found in the map database. The vehicle position will be matched and displayed on the road. The result of the experiment shows that the Double-Star/DR integrated algorithm and map match can improve reliability and the precision of vehicle navigation system efficiently.

In this paper, we present a method based on CCD offering the advantages of high sensitivity, no electromagnetic interference and non-contact in order to measure the thickness of the cooler precisely in high temperature and dust atrocious condition online with real-time and reliable parameter for the control system. By analyzing the principle of CCD and the histogram on the grey scale distribution on the layer's image, the thickness measuring model based on the image segmentation method is founded. According to the image characters of clinker layer, both image segmentation and filtering methods before or after the segmentation are selected. The camera cooling system is designed particularly considering the situation where the camera and the clinker cooler work. After analyzing the shortcomings of the measuring method, an improved one named stereopsis thickness measuring method is present, by means of firstly setting up the stereopsis thickness measuring model before determining the homonymic dots recognizing model, then to abstract the characteristic vector to analyze the recognizing method to establish the precise analyzing model, and finally to complete the experimental research of the thickness measurement based on the image segmentation in order to test the feasibility and to show the results to all.

The fiber micro-drop sensor is a potential tool in different application areas. With the help of a group of fibers, the information of the forming and dripping of a liquid drop is monitored. The fingerprint drop trace provides the information of the liquid to be tested. Some liquids of different types are tested to show the different drop trace. The alcohol solutions of different concentrations are paid more attention to dig the information hiding in the drop trace.

In the simultaneous measurement of the sagittal and tangential modulation transfer function (MTF) of an optical system by using a square object, we analyze various correction factors due to the irregular illumination of the source, the rotation of the square object, and the off-axis effect by the object size for the precise measurement of the MTF. These results can be used in the more exact and effective MTF measurement using the square objects instead of an ordinary pinhole or slit.

Recently with the invention of fiber optic Bragg grating (FBG), new kind of sensors based on FBG is increasingly challengingly the dominating position of some traditional sensors, because this new device has some intrinsic capability: Such as multiplexing, self- referencing, optical and mechanical reliability, anti-interference. Especially it brings the significant advantages that they are non- conductive and lightweight, which can allow for much simpler insulation and mounting designs as the application voltage up to 1000kV or more to day. In addition, it doesn't exhibit hysteresis and provide a much large dynamic range and frequency response than iron- core conventional current transformer (CT). In this paper a current sense device based on electromagnetic force is presented. A FBG is held on the armature of an electromagnetism by one end. As current pass through the iron coil, the magnetic force of the coil lengthens the FBG. Then the Bragg wavelength will change via current. By measuring the change of Bragg wavelength of the FBG we can build a relationship between the tested current and the Bragg wavelength. In this paper the configuration of the new device, the theoretical analysis and measurement results are given.

Aiming at null measurement has the flaws of narrow scale and high cost, authors present a novel measure method with large-scale and low cost to test steeper aspheric surface, namely, simulative compensator and two wave-length phase shifting interferometry. Basing on principle of two-wavelength interferometry and computer-stored compensator, we apply the simulative compensator into the two- wavelength phase shifting interferometer, and it will enlarge the measure scale. In order to decrease the high frequency, compare the standard wavefront produced by simulative compensator with interferential pattern produce by interferometer, the departure between the standard wavefront and interferential pattern is processed the least by adjusting standard wavefront. During the date sample and process, we use sub-Nyquist principle to enlarge measure scale. According to computer simulation result demonstrate that the simulative compensator and two wave-length interferometry presented by this paper can test large departure aspheric surface, the departure of aspheric surface from best fitting sphere attain to thousand wave length. The measure scales of the novel metrology is larger several hundred wavelength than conventional non-null interferometry, and overcome the trivial narrow-scale of null interferometry.

A new type of collimated light tube (CLT) is mentioned in this paper. The analysis and structure of CLT are described detail. The reticle and discrimination board are replaced by a optical-electro graphics generator, or DLP-Digital Light Processor. DLP gives all kinds of graphics controlled by computer, the lighting surface lies on the focus of the CLT. The rays of light pass through the CLT, and the tested products, the image of aim is received by variant focus objective CCD camera, the image can be processed by computer, then, some basic optical parameters will be obtained, such as optical aberration, image slope, etc. At the same time, motorized translation stage carry the DLP moving to simulate the limited distance. The grating ruler records the displacement of the DLP. The key technique is optical-electro auto-focus, the best imaging quality can be gotten by moving 6-D motorized positioning stage. Some principal questions can be solved in this device, for example, the aim generating, the structure of receiving system and optical matching.

A novel transmitted-light differential interference contrast(DIC)system is used for nondestructive measurement of the refractive-index profile(RIP) of an optical fiber. By means of this system the phase of a measured light beam can be modulated with an analyzer. and the phase distribution of a fiber is obtained by calculation of the various interference patterns. The measurement theory and structure and some typical applications of this system are demonstrated. The results of measuring RIPs in graded-index are presented. Both the experimental results and theoretical analysis show that the system takes the advantage and high index resolution and of sufficient measurement analysis show that the system takes the advantage of high index of the optical fiber. The system has strong ability to overcome environmental disturbance because of its common-path design. Moreover, one can use the system to measure the RIP along the fiber axis and acquire an image of the three-dimensional RIP of the fiber.

According to microwave and circuit theory, the transient response model is established after optically controlled photoconductive semiconductor switches (PCSSs) are radiated by ultra-short light pulse. A method for characterizing frequency spectrum characteristics of PCSSs is presented. A deep investigation of the effect of some structural and physical parameters on the frequency characteristics of PCSSs is made. The findings show that the carrier life and absorption coefficient of the photoconductive material for manufacturing the switches, the width of the gap, the pulse width of the incident light, the gap capacitance, lead and parasitical inductance have a great effect on the frequency characteristics of PCSSs. PCSSs have ability to produce THz electromagnetic radiation and can be as Teraherz radiation source.

Phase-shifting interferometry (PSI) as a high accuracy measurement method is widely used in modern measurements. Accurate calibration of phase-shifter is very important if good measurement results are expected from PSI. A new method of on-line calibration for phase-shifter is presented. By constructing a mathematic model for intensity of interferogram associating with the phase-shifter's characters, the coefficients of the function can be solved by introducing Damped-Least-Square methods. Results of computer simulation show a high accuracy after several fast iterations. Experimental results are presented for on-line phase-shift calibration.

We present a polarization analysis system to measure the birefringence of scanning lens. This technique is based on rotating-analyzer ellipsometer. The liquid immersion method is applied to measure the birefringence distribution regardless of the shape of the test lens. In this report, the principle of the two dimensional measurement system and the result of 2-D birefringence distribution in scanning lens are presented.

As a biometrics, iris recognition is becoming an active topic in recent years. Due to constriction and dilation of iris sphincter muscle affected by illumination, iris images should be captured under steady illumination. The principles of our homemade iris capture device and real product are introduced first. This device can be used to capture fine iris images and store them into the computer. Due to changes of head orientation and binocular vergence at different iris acquirement time, a preprocessing method including iris location, normalization, image enhancement and rotation correction is then applied to achieve rotation, shift and scale invariance. Finally the correlation measurement is used to evaluate the performance of this processing.

A multiplayer effective-medium (ML-EM) model is proposed to characterize the microstructure of chalcogenide phase-change thin films grown by magnetron sputtering. Spectroscopic ellipsometric (SE) measurements are carried out on the as-deposited Ge₂Sb₂Te₅ films with various thicknesses ranging from 5.8 to 38.9 nm in the photon-energy region 1.5 to 3.1 eV. The measured data of ellipsometric angles (relative amplitude Ψ and phase difference ▵) are compared with the calculated data of ML-EM model with the help of Levenberg-Marquardt (LM) method. The composition depth profiles, including Ge₂Sb₂Te₅, void and Si, are obtained. The dependence of optical constants on the film thickness is attributed to the various distributions of the compositions in the film.

Thin film is very important in many industries. To perform the functions for which they were designed, the films must have proper thickness, roughness and other characteristics. These characteristics must often be measured, both during and after fabrication. Optical methods used to determining the characteristics of films are usually preferred because they are accurate, nondestructive and require little or no sample preparing. This paper introduces a new method of determining the thickness of thin films using Adaptive Simulated Annealing (ASA) algorithm. Based on the theory of thin film calculating, it uses the spectral reflectance data with the incident light perpendicular to the sample surface over a range of wavelengths to calculate the thickness of thin film. ASA is selected as a global optimization algorithm to characterize the thickness of thin film because it is good at dealing with the multimodal and nonsmooth cost function and it can converge quickly and accurately. The thicknesses of four thin film systems are calculated out to testify the correctness and efficiency of the method and the results are satisfying.

An optical instrument was developed to determine the pesticide residues in vegetables based on the inhibition rate of organophosphates against acrtyl-cholinesterase (AChE). The instrument consists mainly of a solid light source with 410nm wavelength, a sampling container to store the liquid, an optical sensor to test the intensity of transmission light, a temperature sensor, and a MCU based data acquisition board. The light illuminates the liquid in the sampling container, and the absorptivity was determined by the amount of the pesticide residues in the liquid. This paper involves the design of optical testing system, the data acquisition and calibration of the optical sensor, the design of microcontroller-based electrical board. Tests show that the absorption rate is related to the pesticide residues and it can be concluded that the pesticide residues exceed the normal level when the inhibition rate is over 50 percent.

To measure the grinding parameters and geometry parameters accurately for a drill point is essential to its design and reconditioning. In recent years, a number of non-contact coordinate measuring apparatuses, using CCD camera or laser sensors, are developed. But, a lot work is to be done for further improvement. This paper reports another kind of laser coordinate meter. As an example of its application, the method for geometry inspection of the drill flank surface is detailed. Measured data from laser scanning on the flank surface around some points with several 2-dimensional curves are analyzed with mathematical procedure. If one of these curves turns to be a straight line, it must be the generatrix of the grinding cone. Thus, the grinding parameters are determined by a set of three generatrices. Then, the measurement method and data processing procedure are proposed. Its validity is assessed by measuring a sample with given parameters. The point geometry measured agrees well with the known values. In comparison with other methods in the published literature, it is simpler in computation and more accurate in results.

Film is one kind of important record median. Its quality will affect image quality directly. So, it is necessary to study how to assure its quality. Because the situation of film production in dark room, normal detect method could not satisfied the film. In order to avoid to damage film, an infrared detect system is studied. This system is design to set at the position of spreader head. If the defect of film could be found at this position, the beginner of film production line, worker could tread with it in time and reduce waster. The infrared detect system include two sub systems. The two sub system need to detect one position all the time. One sub system is used to detect if there is defect. One CCD camera captures film image. The film image will be monitor by worker through screen. The screen should be set in light room. Another sub system is composed of object lens, image intensifier micro-channel plate and eye lens. If worker find defect from screen, he will inform another worker who worker in dark room. Another worker could find the defect through image intensifier system, and treat with it. The communication method between two workers is sound, not alarm light, because there is dark room. All of the two sub systems use infrared light as light source. The wavelength of light source is 940 nm, which is safe to film. This system is designed for Lekai, the biggest film company of China. This system could find detect early and help worker to deal with it on site, because the detect position is the starting of film production line.

We are developing a new active three Dimension (3D) laser range imaging system based on a pulse light-source and a modulated receiver (PLMR). A double-frequency YAG laser emits light pulses, which are expanded to light cones, with a frequency of 60Hz. A light pulse can illumine a full scene and a modulated image intensifier micro-channel plate (MCP) selects the reflected light with proper optical imaging devices. A Charge Coupled Device (CCD) receives the MCP output signal and generates an intensity image, and two modulated avalanche photo diodes (APD) collects the light splitting from the light pulse as correct intensified values for the intensity image. The system generates a 3D image, which needs a minimum of two different intensity images. These intensity images are obtained with or without illumination of light pulse and with different modulation applied to the MCP. The above imaging times are equal and relate to detection range. We present the best combination of the modulations and illumination conditions, in the meaning of minimum variance, and the relative theoretical analyses. Detection range, measurement resolution and scan frame rate of the system are given considering the influence of background light and circuit noise. Comparing to other 3D imaging systems, our system has the advantage of achieving both long measurement range and high spatial resolution. Potential applications to industry and military of the 3D laser imaging system are also presented.

Based on chromatic polarization interferometry, a novel method for measuring the thickness of optical wave plate is presented. When the resolution power of spectrometer reaches 0.01nm, the measuring precision of the thickness is better than 0.1μm.

A novel method, namely, fiber-coupling zig-zag beam deflection method has been proposed to investigate the attenuation of plasma shock waves in air in this paper. The main innovation of this method is to use a zig-zag laser beam as the probing beam, instead of a straight beam in traditional beam deflection method. The zig-zag beam is formed by eight times successive reflections on a pair of parallel mirrors. Shock waves propagate through the space between two mirrors which contains nine zigzags in the horizontal plane. This space can be designated as the testing field. After the probing beam leaves the testing field, it is coupled into a single mode optical fiber which guides the beam into a photomultiplier to complete the process of photoelectrical conversion. Plasma shock waves are generated during laser ablation of Fe target in air. The laser used in our experiment is a Qswitched Nd: YAG laser operating at wavelength of 1064nm and pulse width (FWHM) of 7ns. The output of 160mJ/pulse of this laser is focused on the surface of the target which is far exceeds the ablation threshold of Fe. When a shock wave propagates in the testing field, it will meet the zig-zag probing beam nine times one after another. Correspondingly, nine deflection signals will be induced by the perturbations of the shock wave, which can be utilized to illuminate the propagating behavior of the shock wave. The whole attenuation process of the shock wave can be demonstrated intuitively only through one experimental curve with the nine deflection signals. From the curve, the average velocity of the shock wave can be calculated out with high and reliable precision. It is found that shock waves attenuate into acoustic waves within 10mm in air because of the inhalement of environmental media. The development of this novel optical technology provides a powerful tool for the detection of shock wave propagation and riches diagnostic methods of shock waves.

Based on laser optical triangulation displacement and grating displacement inspecting principle, optoelectronic non-contact inspecting method and inspecting system for the taper of small-calibre bore are presented. In this paper, the constitute and overall structure of the system are described. Then, the taper inspecting method and principle of the bore are discussed and theoretically analyzed, and also, the corresponding mathematics model is established. As inner diameter measurement is an important parameter for the taper of small-bore, an inner diameter laser non-contact measuring method is presented based on the structure characteristic of the taper of small-calibre bore, which adopted optoelectronic probe sensitive device (PSD) and laser optical triangulation inspecting principle. And then, the laser probe inner diameter measuring system is designed based them. Moreover, the measuring principle, the project of optical system of this measuring system are illuminated in detail in this article. The accuracy of inspecting system is verified by experiment. The results showed that the measuring error of inspecting system is superior to ±0.005, and the inspecting repetition is superior to ±0.003. It indicates that the system can fulfill the inspecting accuracy demand for inspecting the taper of the small-calibre bore, and the inspecting method is applicable.

The subaperture stitching testing method provides a cost-effective means for large field of view, high spatial resolution interferometer. Current approaches to subaperture stitching are mostly limited to plano optics, where only the piston and the tilts are considered. Another implied assumption is that pixels corresponding to the overlapping region between pairs of subapertures are exactly known and given by the nominal translation within a spatial tolerance. This is obviously impractical in the case of aspheric surface. We address the problem here and introduce a geometrical approach to formulate it mathematically. It is essentially a large-scale nonlinear optimization problem, which is very complicated and time-consuming to be solved by conventional method. By virtue of the alternating optimization technique and the successive linearization method, we present a novel iterative algorithm for subaperture stitching interferometry for aspheric surface. It differs from others in that the CAD model of the tested surface is used to determine the overlapping region precisely and efficiently. Subapertures are then simultaneously stitched by minimizing deviations among them, as well as deviations from the nominal surface. As a result, precise prior knowledge of the nulling and alignment motion, which is of six degrees of freedom, is no longer required. Numerical simulations are given to test the validity and computational efficiency of the proposed algorithm.

In order to simplify the complexity and improve the accuracy of convex aspheric lens testing, a novel method is proposed in this paper. In this method, convex aspheric lens is tested in transmitted light at the design wavelength by means of a Mach-Zehnder interferometer. Lens under test and its collimating lens are situated in one arm of Mach-Zehnder interferometer, Hologram Optical Elements (HOEs) acting as the compensator is placed in the proper position in another arm of interferometer. The principle of this setup is analyzed. The design and manufacture of HOEs and spatial filter used in this method are described in detail. In comparison with other methods, the advantages using this method are: (1) complex compensation lenses are not required any more, which simplifies the compensating structure and decreases the costs of measurement, (2) HOEs is easier to be fabricated. A convex-plane aspheric lens as an example is experimented.

According to Generic Reliability Assurance Requirements for Passive Optical Components GR-1221-CORE (Issue 2, January 1999), reliability determination test of different kinds of passive optical components which using in uncontrolled environments is taken. The test condition of High Temperature Storage Test (Dry Test) and Damp Test is in below sheet. Except for humidity condition, all is same. In order to save test time and cost, after a sires of contrast tests, the replacement of Dry Heat is discussed. Controlling the Failure mechanism of dry heat and damp heat of passive optical components, the contrast test of dry heat and damp heat for passive optical components (include DWDM, CWDM, Coupler, Isolator, mini Isolator) is taken. The test result of isolator is listed. Telcordia test not only test the reliability of the passive optical components, but also test the patience of the experimenter. The cost of Telcordia test in money, manpower and material resources, especially in time is heavy burden for the company. After a series of tests, we can find that Damp heat could factually test the reliability of passive optical components, and equipment manufacturer in accord with component manufacture could omit the dry heat test if damp heat test is taken first and passed.

This paper describes two kinds of circuit configuration to design interleaver, which are implemented by a single stage M-Z interferometer whose two arms are connected with ring waveguides. When the two configurations circuits are composed of M rings and N rings, respectively, (2M+2N+1)th-order interleaver characteristics can be realized. For two kinds of structure, design examples including third-order interleaver and fifth-order interleaver and seven-order interleaver are demonstrated. By theoretical analysis of the transmission function, The power transmittances spectrums are calculated, the circuit parameters are gained. Compared the power transmittances spectrums among third-order interleaver, fifth-order interleaver and seventh-order interleaver, it is found that with order of interleaver added, flat-top effect is better, the steeper spectral responses of the stopband and passband are achieved, and power transmittances get closer to square wave.

In this paper, a portable diagnostic instrument for crop quality analysis was designed and tested, which can measure the normalized difference vegetation index (PRI) and structure insensitive pigment index (NRI) of crop canopy in the field. The instrument have a valid survey area of 1m×1m when the height between instrument and the ground was fixed to 1.3 meter. The crop quality can be assessed based on their PRI and NRI values, so it will be very important for crop management to get these values. The instrument uses sunlight as its light source. There are six special different photoelectrical detectors within red, blue and near infrared bands, which are used for detecting incidence sunlight and reflex light from the canopy of crop. This optical instrument includes photoelectric detector module, signal process and A/D convert module, the data storing and transmission module and human-machine interface module. The detector is the core of the instrument which measures the spectrums at special bands. The microprocessor calculates the NDVI and SIPI value based on the A/D value. And the value can be displayed on the instrument's LCD, stored in the flash memory of instrument and can also be uploaded to PC through the PC's RS232 serial interface. The prototype was tested in the crop field at different view directions. It reveals the on-site and non-sampling mode of crop growth monitoring by fixed on the agricultural machine traveling in the field. Such simple instruments can diagnose the plant growth status by the acquired spectral response.

Nanoscale micromotion stage is a key instrument for the reasarch of nanotechnology that provides one-dimensional, two-dimensional, or three-dimensional nanoscale movement. In this paper, a magnetic levitation stage that can provide large range micromotion with nanometer positioning accuracy is proposed, and a height measurement and calibration of the stage using a triplex heterodyne interferometer is presented. This measurement system is mainly consists of three parts: two-frequency He-Ne laser, three heterodyne interferometers and three phase meters, respectively. Each heterodyne interferometer is used to measure the displacement of the magnetic levitation stage in the vertical direction. Then, the triplex heterodyne interferometer can realize the nanometer measurement of three degrees of freedom motion for the stage, that is, translation in the z-axis and rotations around the x- and y-axes. Furthermore, the three heterodyne interferometers have a common planar reflecting mirror, thus, the advantage of this measurement method is that the heterodyne interference can always produce within the travel range wherever the stage travels, this ensure the stage can always have the same height as that of desired position, and this measurement can give fine height consistency.

Firstly we studied the sensitivity of long-period fiber gratings (LPFG) to the refractive index of ambient medium using the coupled modes theory. Then we presented numerical calculation based on long period fiber grating to show the relationship between the resonant wavelength of transmission spectrum and the ambient refractive index. Secondly we analyzed the optical mechanics of the semiconductor oxide film with gas-sensitivity and found that when touching the thin film gas can make its extinction coefficient, absorption coefficient and corresponding refractive index change. Thus we can coat the grating surface with gas-sensitive film and make use of the character that the refractive index will change with the component and density of ambient gas. Furthermore the change will influence the resonant wavelength of transmission spectrum of LPFG therefore we can get information about the gas component and density by way of monitoring changes of wavelength. The LPFG is more sensitive to ambient refractive index than fiber and the sensed signal is wavelength-modulated so the signal is not reflected by the fluctuation of light intensity and the fiber loss. Therefore the LPFG is more sensitive than intensity-type fiber gas sensor.