The design of an optical system is a collaborative effort between the lens designer and the optical test development engineer. Components must be manufactured and assembled in final configurations, often with extremely difficult requirements on surface quality and on alignment. Optical test and assembly engineers are faced with the task of determining methods to measure these parameters to the required accuracies.
To test the shape of aspherical surfaces whose axial curvature is zero, a new holographic interferometer is introduced. The interferometer comprises a cube beam splitter and a plane mirror, and utilizes both first and zero-th order diffracted waves. This paper describes the algorithm to make the computer generated hologram as well as the design aspect of holographic interferometer.
For the majority of optical systems it is typically assumed that the transmitted wavefront has uniform (or Gaussian) amplitude and constant polarization state. This is the default assumption of geometrical optics. This paper considers methods suitable for analyzing systems where this assumption is not valid. Such methods of polarization analysis include polarization ray tracing and polarization aberration theory. Definitions of the basic classes of polarization phenomena and a review of the Jones calculus are included to form a basis for the discussion.
An electro-optical technique is described which permits a rapid, non-destructive analysis of defect structures in compound semiconductor materials to be assessed in real time. The instrument operates in the transmission mode and is sensitive to local variations in the stress-birefringence vector produced from the strain field associated with lattice defect structures, including dislocation networks and slip. A macro-zoom optical system allows varying substrate sizes from 5 mm to 75 mm to be imaged at the full aperture of the monitoring system. Materials with transmission windows in the visible and near infrared wavelengths, out to 2 pm, can be assessed and whole wafer stress-birefringence variations mapped. Macrographs of some common semiconductor materials are illustrated including InP and CdTe.
Scatter in optical systems reduces signal, creates optical noise, limits resolution and has proved to be an unexpected problem in more than one optical design. On the other hand, measurement and analysis of scatter from optical components and systems is a sensitive non-contact source of information that can be used for component acceptance and control of production processes to improve surface finish. The optics required for many of the systems on the drawing board today will need to meet scatter specifications in order to function as intended. Choosing the correct scatter specification for a particular component is not always a trivial task and often when an appropriate specification is chosen there is a problem in getting the measurements taken. The temptation to rely on Total Integrated Scatter (TIS) measurements or on surface profiling via interferometry or stylus systems) is great. Unfortunately predicting scatter from profile measurements is not easy  and TIS is often inappropriate.
We report here a method to measure the cavity spacing of a Fabry-Perot interferometers with error less than several tenth of wavelength. First the central fractional order was obtained from the interference pattern by a OMA system, which consists of diode array and microcomputer, for 32 different wavelength and He-Ne 6328 line . Than by using the method of excess fractions to process data the absolute interference order and the cavity spacing of Fabry-Perot was worked out from data corresponding to at least to 4 different wave-length. Further more , the relative reflection phase dispersion curve for silver Mirror was also obtained by the fitting data method.
The measurement of the surface roughness requires the advanced measuring systems when the mirror finished surfaces are concerned. The use of mechanical method gives the measurement errors and damages the surface. Therefore, the alternative measurement systems must become necessary to investigate. The present study covers the design and development of the electro - fiber - optic system for the experimental purposes. It is found that electro - fiber - optic system results are in a good agreement with the mechanical measurements results.
A Spex Fluorolog 2 has been optically modified to permit the direct measurement of optical absorptance in turbid and fluorescent materials while causing minimal photolysis of those samples. Comparison is made with direct measurements performed in a Diano Matchscan II spectrophotometer.
A new method of accurately testing lens decenter based on the interference of two coherent point sources is presented. The tilt error between two surfaces of the lens can be greatly magnified and detected using two-beam nonlocalized interference fringes produced by a stationary reference surface and the lens surface under test on a rotating air-bearing table. This method has some obvious advantages over existing methods, i.e. , high accuracy, independence of lens size and shape, simplicity, and ease of operation. Both the theoretical analysis and the experiments show that if the radius of curvature of the reference surface and the spacing between the reference surface and the surface under test are properly selected, then a tilt error of about 1 arc-sec on the lens surface can be detected even by the naked eye.
A Modulation Transfer Function (MTF) is defined for a digital binary printer to satisfy demands of MTF for an optical system. For many practical reasons, a Contrast Transfer Function (CTF) is found to be more useful. A binary image model is used to determine major dependencies of CTF from parameters of system (printer-paper) that produced image. A computerized system is described for measurements of the Subjective Quality Factory (SQF) of a digital printer. The SQF can be compared (cascaded) to other electro-optical systems serving as an image quality merit function, characterizing the ability of the whole system to reproduce and print images.
Raster laser scanner system performance requirements and related system parameters are briefly overviewed. Test procedures and equipment that have been developed and utilized to evaluate the performance of raster laser scanning systems are described. Performance data measured with these procedures and equipment are presented for a novel hologon laser beam deflector unit.
Signal loss in a precision-wound parabolic-index multimode optical fiber is investigated using an Optical Time Domain Reflectometer (OTDR). A fiber winding apparatus is designed and built for the production of precision-wound fiber optic bobbins to undergo signal loss measurements. The acquired signal loss data are analyzed and it is noted that high excess loss exist in freshly-wound fiber. The data reveal that a proper heat conditioning of the wound fiber greatly reduces the enormous initial loss. It is believed that the reduction in excess signal loss is due to stress relaxation throughout the fiber pack. It is obvious that the bending stresses at the crossover sites cannot be reduced through a heat conditioning process. The subject of fiber crossovers in precision-wound optical fibers is studied in terms of the winding tension. A theoretical model is developed for the radial stress distribution (in terms of the winding tension) and the results compared with the experimental data.
Even if judged clean on delivery, virtually all optical systems eventually become contaminated during use. Fortunately the low residual level of contamination always present has little effect on the appearance or function of most optical devices. Certain types of optical component, such as those employed in the manufacture of graticules or laser optics, are more sensitive to contamination than others used, for example, in photographic systems but thresholds of acceptance are needed for every application. This requirement presupposes the existence of acceptable methods of measurement. This paper discusses the effect of various forms of contamination on the appearance and function of a variety of optical systems and describes a new technique for inspecting and quantifying, in radiometric terms, the significance of contamination which can build up on all the air glass surfaces of an assembled optical system. The method quantifies the amount of radiation absorbed and scattered by a single particle as assessed by a given measuring instrument which can at the same time be used to measure artefacts of known characteristics on the surfaces of a similar design of reference optical system. Results of measurements undertaken on typical optical systems are presented to illustrate the capabilities of the technique.
Charge carrier diffusion modeling has become a useful tool for computing optically generated crosstalk in photovoltaic focal plane arrays. Although there exists no universal standard for crosstalk optical generators in terms of irradiation geometry, it has been found possible to model a variety of irradiation geometries to fit specific instrument missions and to bracket possible crosstalk magnitudes.