This PDF file contains the front matter associated with SPIE Proceedings Volume 9621 including the Title Page, Copyright information, Table of Contents, Introduction, and Conference Committee listing.

Laser beams far-field alignment is very important for the high power laser facility as well as the frequency doubling crystals adjustment. Traditional beams alignment system and crystals alignment system are separated. That means, they use different optical image systems and CCD cameras, which will occupy larger space and use more money. A new farfield detection system of laser beams is presented with a big diffraction grating (37mm*37mm), a set of optical imaging components and a high resolution CCD camera. This detection system, which is fully demonstrated on the National Laser Facility of Israel, can align high power laser facility beams’ direction as well as the frequency doubling crystals. The new system occupies small space in the spatial filter through off-axial grating sampling. The experimental results indicate that the average far-field alignment error is less than 5% of spatial filter pinhole diameter, and the average crystals’ matching angle error is less than 10urad, which meet the alignment system requirements for beams and crystals.

As the development of the laser-driven technology, the next generation of laser-driven device sets higher requirement for the repetition frequency. The higher repetition gives rise to thermal deposition, which induces thermo-optical effect, elasto-optical effect and bulk displacement. The thermal efficient management is an important approach to dissolve the thermal deposition. The quasi uniform distribution of heat medium is realized by helium cooling Nd:glass slab and the control of edge temperature. In the case, wavefront distortion and depolarization losses is obtained in experiment. Results said that both of them are improved greatly. At the same time, the distribution of temperature, stress and strain and stress birefringence in Nd:glass are analyzed by using finite element numerical simulation method. And the calculation results show that the wavefront distortion and depolarization losses match with the experimental results very well.

With the development of space station technologies, irradiation of space debris by space-based high-power lasers, can locally generate high-temperature plasmas and micro momentum, which may achieve the removal of debris through tracking down. Considered typical square-shaped space debris of material Ti with 5cm×5cm size, whose thermal conductivity, density, specific heat capacity and emissivity are 7.62W/(m·°C), 4500kg/m³, 0.52J/(kg·°C) and 0.3,respectively, based on the finite element analysis of ANSYS, each irradiation of space debris by high-power lasers with power density 10⁶W/m² and weapons-grade lasers with power density 3000W/m² are simulated under space environment, and the temperature curves due to laser thermal irradiation are obtained and compared. Results show only 2s is needed for high-power lasers to make the debris temperature reach to about 10000K, which is the threshold temperature for plasmas-state conversion. While for weapons-grade lasers, it is 13min needed. Using two line elements (TLE), and combined with the coordinate transformation from celestial coordinate system to site coordinate system, the visible period of space debris is calculated as 5-10min. That is, in order to remove space debris by laser plasmas, the laser power density should be further improved. The article provides an intuitive and visual feasibility analysis method of space debris removal, and the debris material and shape, laser power density and spot characteristics are adjustable. This finite element analysis method is low-cost, repeatable and adaptable, which has an engineering-prospective applications.

This study investigates the photoexcitation and ionization of a nitrogen molecule under ultrafast (femtosecond/attosecond) laser pulse irradiation. The real-time and real-space time-dependent density functional (TDDFT) is applied to describe the electron dynamics during the linear and nonlinear electron-photon interactions. The calculations describe well the behavior of the ionization process, and the results of ionization rates show good correspondence with the experimental results. In addition, the effects of near-infrared femtosecond laser pulse trains and the selected extreme ultraviolet attosecond laser pulse trains on electron dynamics are discussed. Theoretical results show that pulse number, laser frequency, and pulse delay are the key parameters for the control of electron dynamics including the electron excitation, energy absorption, electron density, and electron density oscillation.

Ultrashort pulse is important to exploring laser acceleration in many areas, such as fast ignition, advanced radiography capability. Petawatt laser should not only improve output energy on a single beam, but also combine multi-beams coherently. Diagnostics of temporal and phase synchronization is developed for coherent beam combination on a 10ps laser pulse. When two pulses are guided into the diagnostics, one goes through a temporal delay unit and a lens with a focal length 500mm, then arrives at detector unit, the other goes through a phase delay unit and the same lens, and then arrives at detector unit, too. First, temporal synchronization is adjusted by temporal delay unit and monitored by a cross-correlation generator in the detector unit. Second, phase synchronization is adjusted by phase delay unit and monitored by a far field interferogram in the detector unit. In our design, temporal resolution is 6.7fs in temporal synchronization, and phase resolution is 0.007π in phase synchronization. Experiment has proved that this diagnostics is useful to realize synchronization between two ultrashort pulses both in temporal and in spatial.

The influence of phase mismatching on output pulse temporal waveform in the process of second and third harmonic generation at various power densities with different detuning angles is studied based on nonlinear coupled-wave equations. The rules of different frequencies pulse width vary with the detuning angle have been analyzed quantitatively in potassium dihydrogen phosphate (KDP) crystals. The results of numerical simulation show that in high power laser frequency conversion system, the changes of fundamental pulse width are more sensitive to the detuning angle than second harmonic in the process of doubling, and the maximum variation of the full-width at half-maximum (FWHM) of fundamental at different detuning angles is about 19.0%. For tripling, the output pulse width changes of fundamental and second harmonic are sensitive to the detuning angle at high power density, and the maximum variation of their FWHM at different detuning angles are about 19.0% and 19.2%, respectively. However, the SH pulse width almost unchanged at low power density. The results of this study may provide a promising route to determine the best angle for phase matching in the angle adjusting process of experiment.

In this paper, we mainly introduce a novel measurement system of the polarization extinction ratio(PBSBC system). Here, because the main optical components of the system is PBS and PBC, so we call this system PBSBC system. First of all, we introduce the principle of method of measuring the polarization extinction ratio by drawing a circle on the Poincare. Secondly, we present the system block diagram of PBSBC system, and design an experimental system to theoretically and experimentally investigate the performance of this system though the multiple groups of experimental data collected under the same condition. Finally, we could show that it is compatible with the analysis in PBSBC system.

Digital shearing speckle pattern interferometry (DSSPI) is a powerful tool in the measurement of strain, residual stress and the non-destructive testing (NDT). It is widely used in the fields of wood testing, tire inspection and aerospace, etc. The DSSPI system based on the Wollaston prism is attractive because of its compact arrangement, high immunity to disturbance, and, most of all, the ability to measure strain directly. It could show the strain distribution of the measured object by producing fringe patterns. In conventional DSSPI systems, phase-shifting devices are commonly adopted to extract phase information from the fringe patterns, which means dynamical measurement cannot be realized. In this paper, the principle of a novel DSSPI system based on the temporal analysis is presented. Phase information is extracted with the Fourier Transform method instead of the phase-shifting devices in this system. In this way, dynamical measurement is realized. The measuring accuracy is mostly determined by the quality of the fringe patterns (the fringe width and the contrast ratio). There are several factors that influence the quality of the fringe patterns. Here we mainly discuss the influence of the shearing distance and the polarization state. The preliminary experiments with different shearing distances and polarization states are conducted. The ideal shearing distance and polarization state are suggested.

We propose a communication system of Circular Polarization Shift Keying (CPolSK) with homodyne coherent detection in free-space optical (FSO) communication with Gamma-Gamma atmospheric turbulence channel. The system need no polarization coordinate alignment, thus the complexity is reduced. Meanwhile, we derived the closed bit error rate (BER) expression of the system compared with the coherent on-off keying (OOK) system. Simulation results show that CPolSK with homodyne system is highly insensitive to the phase noise and BER performance is greatly promoted compared to OOK modulation, the signal-to-noise ratio (SNR) of receiving is reduced about 8dB when the system has the same BER performance under same conditions.

Supercontinuum (SC) source generated by amplified and dechirped all-normal-dispersion (ANDi) mode-locked Ybdoped fiber laser has many advantages, such as compact structure and low cost. The influences of the seed source, i.e. ANDi laser, on the SC generation are experimentally investigated. The effects of output port and wavelength of ANDi laser on the evolution and bandwidth of SC are studied and discussed. The experiment results show that, the SC resulting from the pulse at conventional nonlinear polarization rotation (NPR) port is much narrower than that from the pulse after NPR port. We also investigate how the SC changes when tuning the output wavelength of an oscillator. The influences on SC of the polarization and power of the incident pump, which generates the SC by propagating through the nonlinear fiber, are also observed.

In high power laser facility, contaminants on optics surfaces reduce damage resistance of optical elements and then decrease their lifetime. By damage test experiments, laser damage induced by typical metal particles such as stainless steel 304 is studied. Optics samples with metal particles of different sizes on surfaces are prepared artificially based on the file and sieve. Damage test is implemented in air using a 1-on-1 mode. Results show that damage morphology and mechanism caused by particulate contamination on the incident and exit surfaces are quite different. Contaminants on the incident surface absorb laser energy and generate high temperature plasma during laser irradiation which can ablate optical surface. Metal particles melt and then the molten nano-particles redeposit around the initial particles. Central region of the damaged area bears the same outline as the initial particle because of the shielding effect. However, particles on the exit surface absorb a mass of energy, generate plasma and splash lots of smaller particles, only a few of them redeposit at the particle coverage area on the exit surface. Most of the laser energy is deposited at the interface of the metal particle and the sample surface, and thus damage size on the exit surface is larger than that on the incident surface. The areas covered by the metal particle are strongly damaged. And the damage sites are more serious than that on the incident surface. Besides damage phenomenon also depends on coating and substrate materials.

Pulsed lasing of Fe:ZnSe polycrystalline sample was demonstrated at room temperature. The characteristics of Fe: ZnSe laser pumped by a non-chain pulsed HF laser were studied. The laser action centered at 4.3 um. The Fe:ZnSe sample were prepared by using thermo diffusion technique. The threshold of absorbed pump HF laser energy of was 20 mJ, the maximum laser energy was E=15 mJ at the efficiency η_ab=15% with respect to the absorbed HF laser energy.

Excimer laser with nanosecond pulse duration can induce low thermal budget processing and heating confinement near the surface region, which make excimer laser annealing process suitable for low-temperature growth of oxide films. This work presented 248 nm KrF excimer laser irradiation processes of ZnO films prepared by a DC magnetron sputtering method. The influence of the laser energy densities on the structural, morphology, optical and electrical characteristics of ZnO films were investigated. The results presented that the crystallinity of ZnO films could be raised obviously by the excimer laser annealing process. The film under laser irradiation with 137 mJ/cm² outputs showed the lowest sheet resistance of 10 kΩ/□ and high visible transmittance (~77.4%). This study indicated that excimer laser annealing is a useful method for the performance improvement of oxide films.

A quantum-enhanced receiver that uses squeezed vacuum injection (SVI) and phase sensitive amplification (PSA) is in principle capable of obtaining effective signal to noise ratio (SNR) improvement in a soft-aperture homodyne-detection LAser Detection And Ranging (LADAR) system over the classical homodyne LADAR to image a far-away target. Here we investigate the performance of quantum-enhanced receiver in Λ-type soft aperture LADAR for target imaging. We also use fast Fourier transform (FFT) Algorithm to simulate LADAR intensity image, and give a comparison of the SNR improvement of soft aperture case and hard aperture case.

We propose a detection scheme called Stokes vector direct detection (SV-DD) to realize high electrical spectral efficiency and cost-effective optical communication , which is more suitable than coherent detection for short-reach. At reception, the signal is detected in Stokes space.SV-DD is different from conventional DD technique in the parts of not requiring polarization tracking or narrow band optical filtering for carrier extraction. 2nd-order nonlinearity due to photodetection is a fundamental limitation for DD. The conventional SV-DD systems use 2*4 coupler in the receiver, it makes 2nd-order nonlinearity much serious since there are four photodetections or two balance photodetections. In this paper, we experimentally demonstrate the SVDD scheme in single-carrier system using a 3*3 coupler with three photodetections in the receiver.

The centroid estimation, wavefront reconstruction and environment (typically temperature) are the main error sources of the Shack-Hartmann wavefront sensor (SHWS). In this paper, theoretical and experimental studies are conducted to analyze the effect of ambient temperature on the measurement accuracy of SHWS. The spot arrays corresponding to ambient temperature varied from 20.5 to 24 degrees are obtained by using the thermal analysis features in ZEMAX. The wavefronts are then reconstructed by home-made software from these spot arrays. By using the wavefront diffracted by a single mode optical fiber and the SHWS, the experiment setup is built to verify the results obtained by theoretical analysis. The results obtained by theoretical analysis and experiments are coincident well. The variation of the wavefronts measured by SHWS will be smaller than 0.06 nm RMS if the ambient temperature variation is controlled within 0.1 degree. The range of temperature within ±2 degrees, the max wavefront deviation is 2.12 nm. This research will be of guiding significance to ambient temperature control in high precision wavefront error metrology by using SHWS.

The properties of 915nm laser power beaming to monocrystal silicon solar cells are investigated by measuring IV curves, temperature and etc. With the illumination intensity increased from 0.04W/cm² to 0.58W/cm², short-circuit current increases almost linearly from 0.14A to a maximum value of 3.07A. While the maximum power output peaks at a lower irradiation intensity of 0.46W/cm², which can be also regarded as a turning point where IV curves begin to deteriorate from normal ones to oblique lines. During the period, the fill factor decreases continuously from around 74% to a stable value of 25%. To understand the experiment more clearly, theoretical analyses are conducted by virtue of Lambert W function. Based on the analyses, it can be concluded that the primary culprits influencing the cell’s output performance are the temperature and series resistance.

Laser-induced breakdown spectroscopy (LIBS) is characterized as a powerful tool in in-situ online analysis with its fast and multiple detecting abilities. But in the area of detecting trace sample in aqueous solution of low concentration, the turbulence, scattering, absorbance and cooling effect of liquid medium limits its performance. Traditional method includes liquid jet, liquid-solid transformation and pre-concentration on other medium, yet the procedure of sample preparation is complicated and time consuming. In this work, we propose a new method to achieve pre-concentration, in which filter paper and electro-spray ionization (ESI) are used. In our experiment, we choose MnSO₄ as sample. The surface of filter paper is sprayed with MnSO₄ aqueous solution of different concentration by an ESI. The pulsed laser is focused on the surface of filter paper and the plasma is formed in the focusing area. Through an optical fiber the spectrum of plasma is detected by a spectrometer. The ESI system, pulses generator system and the UI on PC are home-made. The spectra lines of Mn at 257.6nm, 259.4nm and 260.6nm are analyzed. Results show that the limit of detection at 257.6nm is sub-ppb and the R² of calibration curve is more than 0.93. Compared with traditional method, like soak and drip processing, our method can increase the concentration of the sample by simply expanding spraying time, achieving a higher signal-to-noise ratio (SNR) and a lower limit of detection (LOD). In addition, the consumption of sample solution is as low as several hundred μl in each detection.

According to the special requirements of combination film in 10kW diode laser cladding source, the polarization combination film at 915nm was designed and grew. Film system is designed at different film materials based on the design theory. The non-QWOT film is optimized using the needle optimization and double sided coating by Optilayer software. The film was used in the 10kW diode laser source after high temperature aging testing. The film formed by Ta2O5 is very stable under IBAD, which can meet the reliability of 10kW diode laser cladding source in industry

Many studies have indicated that the optimum measurement approach for winds from space is a pulsed coherent wind lidar, which is an active remote sensing tool with the characteristics that high spatial and temporal resolutions, real-time detection, high mobility, facilitated control and so on. Because of the significant eye safety, efficiency, size, and lifetime advantage, 2μm wavelength solid-state laser lidar systems have attracted much attention in spacebased wind lidar plans. In this paper, the theory of coherent detection is presented and a 2μm wavelength solid-state laser lidar system is introduced, then the ideal aperture is calculated from signal-to-noise(SNR) view at orbit 400km. However, considering real application, even if the lidar hardware is perfectly aligned, the directional jitter of laser beam, the attitude change of the lidar in the long round trip time of the light from the atmosphere and other factors can bring misalignment angle. So the influence of misalignment angle is considered and calculated, and the optimum telescope diameter(0.45m) is obtained as the misalignment angle is 4 μrad. By the analysis of the optimum aperture required for spacebased coherent wind lidar system, we try to present the design guidance for the telescope.

According to the problem of gain medium cross section high illumination and non-uniformity, which is caused by the laser rod amplifier non-imaging pump style. Orthogonal test design method is used to research the effect of absorption coefficient, gain medium radius, number of xenon lamps, center distance of xenon lamps and gain medium on gain uniformity. The rod amplifier which is made up by the above four elements, its gain medium cross section illumination distribution is simulated by ASAP. The results show that center distance of xenon lamps and gain medium, number of xenon lamps have very little influence on the gain uniformity. When absorption coefficient equal to 5.1 cm^-1, gain uniformity will reach the optimum. Under the circumstance of other three elements are equal, the bigger is the gain radius, the smaller slope reflection curve, and the better gain uniformity.

The deformation of KDP crystals caused by gravity and mounting force can induce the phase mismatch, resulting in the decrease of frequency conversion efficiency. Loading strips are used to reduce the distortion in some existing methods, but it is difficult to fabricate. In order to improve the surface shapes of KDP crystals, small loading plates are used instead of loading strips. The mounting configuration is analyzed by finite element methods (FEM) and the position of the loading plates is optimized by adaptive single-objective algorithm. The results show the effectiveness of the mounting configuration in reducing the gravitational sag of KDP crystals.

Illumination uniformity of the illuminator is significant for achieving stringent critical dimension (CD) control for lithography machine. In order to achieve high uniform illuminating, there is an urgent demand of accurate measurement for illumination uniformity. The difficulty for accurate measurement of illumination uniformity for the illuminator mainly lies in two aspects: the illumination plane is large; excimer laser pulse energy is variable from pulse to pulse. In this work, a spot sensor based 2-dimension scanning method for illumination uniformity measurement is proposed, where the spot sensor in combination with a 2-dimension moveable stage is located in the illumination plane of the illuminator is used to scan the illumination plane point-by-point so as to obtain the whole irradiation distribution. To improve measurement accuracy, the energy sensor of the illuminator serves as the reference and monitors each pulse in real-time showing benefit of excimer laser pulse energy fluctuation eliminating. Secondly, the used spot sensor is modified for strict synchronization control of the spot sensor and the energy sensor so that the measurement precision can be improved. Measurement results show that X direction transient non-uniformity, Y direction transient non-uniformity and X direction integral non-uniformity of the illuminator are 5.14%, 5.55% and 2.16% respectively with a measurement uncertainty of 0.31% (k=2). It is proved that the proposed method is effective and helpful for further system optimizing and alignment.

The chirally-coupled core fibers exhibit excellent single mode performance without any external mode managements. In this paper, we numerically investigated effects of fiber parameters including side core size, NA, helix pitch and offset distance on high order modes loss. A general range of parameters was given for fiber design. The results indicate that to achieve high loss for side modes, the fiber requires side core diameter ranging at a dozen micrometers with a numerical aperture 0.09 and the helix pitch taking values in millimeter magnitude.

We have demonstrated a kW continuous-wave ytterbium-doped all-fiber laser oscillator with 7×1 fused fiber bundle combiner, fiber Bragg grating (FBG) and double-clad gain fiber fabricated by corresponding technologies. The results of experiment that the oscillator had operated at 1079.48nm with 80.94% slope efficiency without the influence of temperature and non-linear effects indicate that fiber components and gain fiber were suitable to high power environment. No evidence of the signal power roll-over showed that this oscillator possess the capacity to highest output with available pump power.

The non-collinear phase-matching in Potassium Dideuterium Phosphate (DKDP) crystal is analyzed in detail with signal pulse of center wavelength at 808 nm and pump pulse of wavelength at 526.5 nm. By numerical analysis, parametric bandwidths for various DKDP crystals of different deuteration level are presented. In particularly for DKDP crystals of 95% deuteration level, the optimal non-collinear angles, phase-matching angles, parametric bandwidths, walk-off angles, acceptance angles, efficiency coefficients, gain and gain bandwidths are provided based on the parameter concepts. Optical parametric chirped pulse amplifier based on DKDP crystal is designed and the output characteristics are simulated by OPA coupled wave equations for further discuss. It is concluded that DKDP crystals higher than 90% deuteration level can be utilized in ultra-short high power laser systems with compressed pulses broader than 30fs. The disadvantage is that the acceptance angles are small, increasing the difficulty of engineering regulation.

By using Nd:YAG/Cr:YAG/YAG composite crystal as gain media, a passively Q-switched LD side-pumped laser with high average output power, working at 1064 nm, is set up. The 1064 nm laser output power increases linearly with the pumping light power and the maximum average output power of 83.68 W is observed. With the help of a KTP nonlinear crystal, 532 nm laser pulses with the corresponding pulse width of 210 ns and the repetition rate of 21.2 kHz are obtained under the maximum LD pumping light of 187.5 W. The average output power of 532 nm laser is 27.2 W. The singlepulse energy is 1.28 mJ and the peak power is 6.1 kW. The optical-to-optical conversion efficiency of LD pumping light to 532 nm output light is 14.72%.

We present a laser system design for an absolute gravimeter based on ⁸⁷Rb atom interferometer. By skillful design, lasers with 9 different frequencies are based on two diode lasers including tapered amplifier. Two electrical feedback systems are used for laser frequency stabilization and the Raman lasers generation respectively. All other lasers are based on two Raman lasers and realized with frequency shift by acoustic optical modulators. This laser system not only has the compact and simple construction, but meets all requirements for laser power and frequency controlling for the atom interferometer. It has the characteristic of reliability and integrity.

In order to research the laser damage mechanism of high transmission single layer optical thin film for fused silica glass, finite element method was used to calculate laser induced damage threshold (LIDT) and an optical test system with a nanosecond solid-state lasers was set up to determine the LIDT according to standard of ISO 11254. Firstly, finite element model was created at COMSOL multi-physics software and the temperature of inclusion in the optical thin film was calculated with different physical parameter. It is found that temperature at center of the inclusion firstly decreases and then increase with the increasing of inclusion depth. It is also found that the temperature constantly increase with the radius increasing from 20nm to 100nm. Moreover, the inclusion temperature for MgF₂ thin film is higher than that of CaF₂ thin film. Lastly, LIDT were measured by the optical test system, and the average value of LIDT is 3.7J/cm² for MgF₂ thin film and 4.6J/cm² for CaF₂ thin film, which is well fit with the value calculated by COMSOL software. The study shows that finite element method is an effective method to calculate LIDT for optical thin film and impurity has significant impact on the LIDT of optical thin film and therefore decreasing the density of the impurity would increase the LIDT of the thin film.

A polarization-converting system is designed by using axicons and wave plate transforming naturally polarized laser to linearly polarized laser at real time to resolve difficulties of generating high-power linearly polarized laser. The energy conversion efficiency reaches 96.9% with an enhancement of extinction ratio from 29.7% to 98%. The system also keeps excellent far field divergence. In the one-way SHG experiment the double frequency efficiency reached 4.32% using the generated linearly polarized laser, much higher than that of the naturally polarized laser but lower than that of the linearly polarized laser from PBS. And the phenomenon of the SHG experiment satisfies the principle of phase matching. The experiment proves that this polarization-converting system will not affect laser structure which controls easily and needs no feedback and controlling system with stable and reliable properties at the same time. It can absolutely be applied to the polarization-conversion of high power laser and enhance the SHG efficiency and the energy efficiency.

Ion mobility spectrometry (IMS) is widely used in the field of chemical composition analysis. Faraday cup is the most classical method to detect ions for IMS in the atmospheric pressure. However, the performance of Faraday plate was limited by many kinds of factors, including interfering electromagnetic waves, thermal(Johnson) noise, induced current , gain bandwidth product, etc. There is a theoretical limit in detection of ions at ambient condition which is approximately 106 ions per second. In this paper, we introduced a novel way using laser-induced fluorescence (LIF) to bypass the limitation of Faraday plate. Fluorescent ions which were selected by IMS get excited when they fly through the laser excitation area. The fluorescence emitted by the excited ions was captured exponentially and amplified through proper optoelectronic system. Rhodamine 6G (R6G) was selected as the fluorochrome for the reason that excitation wavelength, emission wavelength, and fluorescence quantum yield were more appropriate than others. An orthometric light path is designed to eliminate the adverse impact which was caused by induced laser. The experiment result shows that a fluorescence signal from the sample ions of the IMS could be observed. Compared with Faraday plate, the LIF-IMS may find a potential application in more system at the atmosphere condition.

40 mW of dual-frequency power from a microchip diode-pumped solid-state Nd:YAG laser is presented. A coupled cavity is used as a mode selector and enforce a single frequency oscillation. An electro-optic crystal and a pair of quarter-wave plates are used to obtain dual frequency oscillation, respectively. By changing the applied voltage and the angle between two fast axes of the wave plates, the frequency difference of the two frequency is changed. Using dual quarter-wave plate method, we obtained 40 mW of dual-frequency laser output when the absorbed pumping power was 690 mW.

In order to study the influence of atmospheric turbulence on earth observation system, the atmospheric structure parameter was calculated by using the weak atmospheric turbulence model; and the relationship of the atmospheric coherence length and high resolution remote sensing optical system was established; then the influence of atmospheric turbulence on the coefficient r0h of optical remote sensing system of ground resolution was derived; finally different orbit height of high resolution optical system imaging quality affected by atmospheric turbulence was analyzed. Results show that the influence of atmospheric turbulence on the high resolution remote sensing optical system, the resolution of which has reached sub meter level meter or even the 0.5m, 0.35m and even 0.15m ultra in recent years, image quality will be quite serious. In the above situation, the influence of the atmospheric turbulence must be corrected.

Strictly controlling the cleanness of transport mirror surface in high power laser system has an important significance. Removal efficiencies of dust in different sizes and on different positions of the transport mirror surface are studied, by using the air knife blowing method with different inlet pressures and installation positions. Full experiments and range analysis show that the air knife blowing method is an effective way to control the cleanness of the transport mirror surface. The removal efficiency of dust particles in different sizes and positions of the transport mirror surface is better when inlet pressure is 0.9 MPa and the air knife installation position is 3 mm. Besides that, some simulations on flow fields are conducted. The simulation results and the experimental results have a good consistency.

In recent years, high frequency errors of mirror surface are taken seriously gradually. In manufacturing process of advanced telescope, there is clear indicator about high frequency errors. However, the sub-mirror off-axis aspheric telescope used is large. If uses the full aperture interferometers shape measurement, you need to use complex optical compensation device. Therefore, we propose a method to detect non-spherical lens based on the high-frequency stitching errors. This method does not use compensation components, only to measure Aperture sub-surface shape. By analyzing Zernike polynomial coefficients corresponding to the frequency errors, removing the previous 15 Zernike polynomials, then joining the surface shape, you can get full bore inside tested mirror high-frequency errors. 330mm caliber off-axis aspherical hexagon are measured with this method, obtain a complete face type of high-frequency surface errors and the feasibility of the approach.

A novel solution of frequency locking based on beat frequency detection in homodyne coherent receiver is presented and experimentally demonstrated. The beat frequency detection, using two beat frequency signals generated by a balance detector module, is easily to eliminate the noise introduced during long distance transmission. Furthermore, FPGA, as the core of the control unit, is adopted to change the resulting frequency of OVCO on the basis of the frequency deviation. The proposed scheme is tested more efficiency and higher stability than the previously single path feedback loop.