NO2 vertical column density (VCD) is measured by direct-sun differential optical absorption spectroscopy (DS-DOAS). When cloud exists in the field of view of instrument, measurement results of this technique are influenced by multiple scattering of particles in cloud. To solve this problem, a new method is proposed. Simultaneously inversing O4 VCD is used to determine whether there is cloud in the field of view or not. Then the NO2 VCD is corrected. Statistics show that the variation amplitude of O4 VCD is 6% due to inversion error and atmosphere disturbance in cloud-free sky. If the magnitude of relative variation of O4 VCD is larger than 6%, there is cloud in the field of view. This method is used to correct NO2 results from a four-day field measurement. It is proved that this method can effectively improve the measurement precision of DS-DOAS when clouds exist in the field of view.

Understanding vertical profiles of atmospheric turbulence characteristics is one of the most important problems for theoretical and applied research in the fields of atmospheric optics. Stochastic parallel gradient descent (SPGD) algorithm is proposed for turbulence profile mode fitting. Based on the generalized Hufnagel-Valley model, atmospheric turbulence profile models for different seasons and time of day in Hefei have been developed to fit each observed average C2N vertical profile by SPGD algorithm. The results show that, not only the obtained turbulence mode show best accordance with the observed average profiles of C2N over the whole atmosphere, but also the optical turbulence characteristic parameters of the obtained turbulence modes are in good agreement with those for the average profiles of C2N. The investigation is a useful exploration for developing a “universal method” for turbulence profile model fitting based on the generalized Hufnagel-Valley model.

A novel frequency quadrupling scheme based on a dual parallel Mach-Zehnder modulator (MZM) for the generation of optical millimeter signal and modulation of the vector signal is demonstrated. The traditional frequency quadrupling modulation scheme, which modulates data on both +2 and -2 order optical sidebands and will cause the constellation overlapping after photodetector (PD) detection, can only carry the on-off keying data format such as not return to zero (NRZ). The proposed scheme encodes the electrical vector signal on the -1 order optical sideband, and a pure radio frequency (RF) tone at +3 order optical sideband. Therefore, phase and amplitude information will be correctly preserved after detection. Besides, a frequency quadrupling scheme is employed to reduce the bandwidth requirements of the electrical and optical components of the transmitter. A proof of concept and simulation is conducted by using a 6.25×108 symbol/s QPSK signal at a carrier frequency of 60 GHz , which indicates that the error vector magnitude (EVM) penalty is negligible after transmission over 20-km single-mode fiber (SMF).

The intermodulation distortion greatly deteriorates the receiver sensitivity of intersatellite microwave photonics link in the range of high input signal power. The situation of N quadrature phase shift keying (QPSK) modulation signal input is considered and the intensity modulation/direct detection (IM/DD) intersatellite microwave photonics link model is presented. An exact analytical solution for any harmonic and intermodulation components of receiver signal is deduced with the method of Fourier expansion, Fourier transform/inverse Fourier transform and Graf addition theory. Combined with the number of third-order intermodulation distortion, the relationship formula between receiver optical power and signal-to-noise and distortion ratio (SNDR) is derived. The analysis concentrates on the relationship between receiver sensitivity of intersatellite microwave photonic link and the number of channels, the modulation index under different modulation modes. When the modulation index is small, the receiver sensitivity is robust against the change of channel number. The receiver sensitivity increases and then decreases as the increase in modulation index. It shows that an optimum modulation index can maximize the receiver sensitivity of link.

Performance of free-space optical communication (FSO) system fluctuates greatly, which is influenced by atmospheric turbulence. Research about evaluating system error performance according to parameters of system and atmosphere is a subject with certain practical significance. Based on both optical turbulence channel and photoelectric detection model, a mathematic simulation model of error performance for FSO system is established. A modified expression of bit error rate for FSO system through turbulent atmosphere is proposed, and an experiment of 24 hours′ duration is carried out to test the expression. It shows that intensity probability distribution has a significant influence on system error performance. The results of original expression are inconsistent with experimental data on certain conditions, and the modified expression has better applicability and accuracy. The modified expression can lead to an efficient performance evaluation and provide reference to correlative researches.

The static waveband grooming algorithm is studied. Waveband switching can effectively decrease the ports of wavelength switching. But the granularity of waveband is difficult to be set when it is constant. When the waveband granularity is large, the switching ports can be decreased while the waveband utilization is low. When the waveband granularity is small, the waveband utilization is high while the switching ports can be increased. To solve this problem, a multi-granularity waveband scheme is proposed. The static traffic grooming is similar to multicast routing in some degree. So the multicast tree is used to solve the waveband grooming problem. In order to decrease the connection ports between the waveband switching plane and wavelength switching plane, the same destination grooming scheme is adopted. A new waveband auxiliary graph is proposed for this grooming scheme. The simulation result shows that the scheme proposed can decrease the waveband switching ports and improve the waveband utilization ratio effectively.

One of the major limitations of optical phase conjugation (OPC) for dispersion and nonlinearity compensation in optical fiber communication systems is that the power profile along the communication links should be symmetrical with respect to the optical phase conjugator. However, such a power profile is difficult to be realized in practical systems in which the communication link is composed of uniform fibers and periodic amplification using erbium-doped fiber amplifiers. It is numerically demonstrated that the difficulty can be overcome if the OPC is used in combination with pulse prechirp. Pulse prechirp can greatly reduce the interplay between the dispersion and nonlinearities and improve the communication performance. It is also shown that the effect of intra-pulse Raman scattering on the communication scheme is much smaller than that of third-order dispersion even for picosecond ultrashort pulses. Thus, more effective compensation can be achieved if spectral phase conjugation is used, instead of temporal phase conjugation for the scheme. The scheme is simple and effective, and it eliminates the need for special design or significant modification of the communication link.

Based on the model of the spatial coherent optical communication system under the influence of the atmospheric turbulence and the plane-wave propagation model of aperture averaging, by using of numerical simulation, under the weak irradiance fluctuation condition the influence of aperture averaging including the atmospheric turbulence inner scale and outer scale is investigated on the bit-error rate and the optimum receiver aperture diameter of the coherent optical communication system. The results show that aperture averaging can decrease the bit-error rate effectively; the improved effect of aperture averaging on the bit-error rate is more obvious for the higher original SNR, the shorter transmission distance, the longer wavelength, the larger value of the phase compensation mode J and the receiver aperture diameter which is closer to the optimum value; aperture averaging affects the optimum value of the receiver aperture diameter, and if the value of the phase compensation mode J is larger, the influence is more obvious; the bit-error rate and the optimum receiver aperture diameter will increase with the increase of atmospheric turbulence inner scale and decrease with the decrease of atmospheric turbulence outer scale. This will provide the necessary theoretical basis for the design of a coherent optical communication system.

Based on acousto-optic refraction, a non-invasive method used for detecting acoustic pressure of the focus of focused ultrasound is proposed. By studying the specific relationship between acoustic pressure of the focus and the ray deflection when a parallel beam whose diameter is less than the wavelength of the sound wave is crossing the focus of the focused ultrasound, a relational model between the maximum deflection distance of the ray and the change of the focus acoustic pressure is established, thus the peak acoustic pressure of the focus is calculated. In order to verify the theoretical model, the concave sphere type focused transducers are used for experiment research. By comparing with the result measured by optical fiber hydrophone, the feasibility of the theoretical model is proved. The results show that the facula images acquired in experiment are consistent with the results of theoretical analysis, and the relative error between the acoustic pressure of the focus measured by current method and that by using optical fiber hydrophone is less than 15%, which proves the feasibility of the method. And it can be used to detect the peak acoustic pressure of the focus quantificationally. The proposition of this model provides the experimental and theoretical evidence for that the acousto-optic refraction effect can be used to measure the whole focused ultrasound field quantificationally.

A new method is presented to measure aerosol scattering phase function and visibility, and an experimental system which uses semiconductor laser as the light source and charge coupled device (CCD) as the detector of scattering light is constructed. The grey level of 15°~45° distribution is measured by the system. The aerosol scattering phase function is fitted and the atmospheric visibility is calculated based on the method. The results have good agreement with the results of POM sky radiometer and Belfort visibility meter, and this method is feasible to measure aerosol scattering phase function and visibility.

The defocus blur problem of catadioptric omnidirectional imaging, which is caused by aperture and mirror curvature, becomes more severe along with introducing high-resolution sensors and large aperture. One design of catadioptric omnidirectional imaging system for defocus deblurring is proposed. The defocus blur of catadioptric omnidirectional imaging is analyzed in theory, and the relation between point spread function of omnidirectional image and scene′s spatial points or the position of virtual features is established. Then, the defocus blur kernel of omnidirectional image is spatially invariant when image plane is moved in a particular pattern during image integration. A deconvolution algorithm is used for the defocus blur omnidirectional image restoration to obtain all sharp omnidirectional images. The method is effective for catadioptric omnidirectional image defocus deblurring, and has an important meaning in improving catadioptric omnidirectional imaging quality and promoting applications in related fields.

In order to build a proper maneuvering target model for the infrared fisheye warning system, the target moving characteristics on the image surface are analyzed. A modified constant velocity model is presented by virtue of the system′s higher sampling frequency. Comparing with the current statistical model, its tracking accuracy is analyzed theoretically. It is found that, for the infrared fisheye warning system with high sampling frequency, the tracking accuracy of the constant velocity model can reach that of the current statistical model. With Kalman filtering, the analog track is used for the tracking experiment, and it is proved that the result above is correct. Above all, this model, with its simple structure and less computation, is available for the infrared fisheye warning system.

For the shortcomings of methods used to improve the image spatial resolution of current linear charge coupled device (CCD) imaging system, a new sampling method is proposed, and a high-resolution imaging system is designed. Two same linear CCD cameras are fixed with specific spatial arrangement, namely both camera 1 and camera 2′s CCD scan the object with a tilt angle θ, and image correction and pixel interpolation are also used for getting high-resolution image. The experimental results show that, compared with the regular scanning mode equipped with a signal camera and θ=0°, in our method cameras with slant angle θ=60° enables the image spatial resolution doubled, and keeps the field of view unchanging. It is easy to realize the designed system in engineering, very economical and convenient to maintain it, and only using the existing imaging device to obtain higher-resolution images.

The imaging matching model of the digital domain time-delay integral (TDI) complementary metal-oxide-semiconductor (CMOS) sensor under the staring gesture is designed in order to realize high-resolution staring imaging, attitude which satellite changes relative to orbital coordinate system staring on satellite staring tracing imaging is derived. The coordinate transformation method is used to real-time compute the time of the line transfer process in the staring, the method of Monte Carlo is used to statistically calculate the influence of imaging under the satellite′s attitude point precision and stability in the mode of staring imaging. The TDI CMOS prototype and the minitype three-axis air bearing table constructed for attitude control are used to simulate the digital domain TDI CMOS staring imaging. Experimental results show that the satellite′s attitude control accuracy will cause the vertical image velocity mismatch and the residual image of transverse matching in the process of imaging. The higher imaging integral series is, the greater the signal-to-noise ratio (SNR) of the image will be. Integral series increase has a higher requirements to the satellite attitude. The control accuracy of the attitude angles and attitude angular velocity of the staring imaging simulation platform is better than 0.05° and 0.005°/s, the integral series 48 can meet the image-quality requirement.

In order to measure radial distortion of each pixel in optical imaging plane, a carrier-frequency fringe phase analysis using wavelet transform method is proposed to measure the radial distortion. The phase of a vertical sinusoidal fringe is used as a carrier of the radial distortion. A relation between the radial distortion and the radial modulated phase is derived. Then, the fundamental spectrum of the distorted fringe pattern is analyzed by frequency estimation and phase estimation of Gabor wavelet transform. Since there is zero distortion at the center of the distorted (deformed) fringe pattern, the local frequency and phase at the center is used to construct the fundamental spectrum of the original fringe pattern. Thus the 3D modulated phase of the distorted (deformed) fringe pattern is extracted and converted to the radial distortion of each pixel. Using a calibration formula and a cubic convolution interpolation algorithm, a distorted colored image is calibrated. Experimental results demonstrate the proposed method is feasible.

In lithographic alignment, alignment labels located on the mask and wafer are generally made by two gratings of slightly different periods. The relative position between the mask and wafer is detected by phase information of moiré fringes. In practical application, the direction of moiré fringes is not only related to geometric position of alignment labels, but also position of CCD. To propel the method of lithographic alignment into practice, phase distribution law of general gratings is analyzed from rectangle gratings to moiré fringes. Based on phase characteristics of moiré fringes, effects of geometric positions of the template, wafer and CCD on alignment precision are emphatically analyzed. Mathematical-relation models between the alignment deviation and theoretical displacement are also established. Research results show that the maximal alignment error is theoretically less than 0.002 pixel without an angular displacement when the displacement is less than 0.4 pixel.

Combined with the temporal and frequency domain fringe analysis methods, a new phase shifting shadow moiré technique to relax the restriction on the phase shift between frames is proposed. The proposed algorithm can extract the precise phase using three or more interferograms in an arbitrary sequence. The first stage of the algorithm is to estimate the heights and determines the frame differences based on the spiral phase transform technique. The second stage uses the generalized least-squares method to extract the temporal phase. Experimental results show that high accuracy phase estimates are obtained by the proposed algorithm. It is shown the standard deviation of the proposed method is less than 3×10-3 mm. The proposed algorithm gives an effective solution to improve measurement accuracy of shadow moiré.

In the photographic measurement with high precision, the image processing precision plays a crucial role in the overall measurement accuracy. In the process of imaging, the discrete sampling of the feature points by cameras causes a distortion between the received signal and the original image, which brings errors in image processing. By analyzing the total energy, the dispersion radius of energy distribution of the feature points and the image processing windows, and based on the relation of the feature point center position, extraction error and the standard deviation of the energy density function, an error compensation method is proposed for discrete sampling. According to the method, only once calibration of the compensation parameters is needed for any camera and algorithm, and the image processing precision can be improved significantly. The experiments show that for the centroid method and the Gaussian fitting method, the image processing precision can be increased to 0.03 pixel.

A modified method based on mirror rotational symmetry is developed to determine the absolute flatness deviations of optical elements in synchrotron radiation. The novel method is described in terms of functions that are symmetric or antisymmetric with respect to reflections at y axis. Absolute deviations of three flats can be obtained when mirror asymmetric errors are removed by N-position rotation average method. The formulas are derived for measuring the absolute surface error of the rectangular flat, and experiments on high accuracy rectangular flat are performed to verify the method. Compared with the measurement results obtained by Zygo′s three-flat application, our method is calibrated to an accuracy of better than λ/500 (λ=632.8 nm) root mean square (RMS) on height and 0.93 μrad RMS on slope error. The theoretical derivation, experimental results, and error analysis are presented.

To realize the fast ignition experiments, deep and quantitative research needs to be taken on the large aperture off-axis paraboloidal mirror (OAP) which is the core component in the high-energy petawatt laser focusing system, in order to provide an accurate basic theory for the OAP structure model selection and precision adjustments. This paper uses a numerical calculation method based on the rigorous vector diffraction theory combining with wavefront aberration analysis, by which the physical optical imaging characteristics of a large aperture and far off-axis OAP are obtained. First, using parallel light incidence, a conclusion can be obtained that the tolerances of OAP translation and revolving around its symmetric axis are closely related with its focal depth. When the optical axis misalignment occurs, astigmatism will play a leading role in the influence on the optical spot which can be described qualitatively by a structural factor. Then, when the incident light has a divergence angle, the best image plane location will change and coma is produced to decrease the power density of the optical spot owing to the asymmetry of OAP. The discussion of the influence affected synchronously by the structural parameters of OAP is also presented.

A single mode infrared (IR) fiber laser using PbSe quantum dots as active medium is proposed according to the observed transmission electron microscope (TEM) images, absorption and emission spectra of the sodium-boron-aluminosilicate glass doped with PbSe quantum dots prepared before. The rate equations and lasing oscillation equation in a resonator are solved numerically. The optimal pumping wavelength, fiber length, doping concentration and reflectance of output mirror are obtained by using genetic algorithm. There is evidence that the quantum dots fiber laser (QDFL) possesses the saturated pumping power of 2 W, the maximum output of 1.36 W for 1676 nm lasing wavelength, and the pumping efficiency of 68%. Compared with the conventional fiber lasers that are doped with rare earth ions (e.g. Yb3+, Er3+), QDFL has characteristics of high pumping efficiency, low exciting threshold, adjustable doping density, and short saturated fiber length. The proposed QDFL can be developed into a novel multi-wavelength and wavelength-tunable laser due to lasing wavelength depending on the size of quantum dots.

Output charactaristic of external resonator PbWO4 Raman laser excited by nanosecond pulse is studied. An actively Q-switched Nd:YAG laser is used as the pumping source, with pulse width of 31.4 ns and the maximum output energy of 200 mJ at 1064 nm. The Raman laser cavity is a flat-concave one. The relation between the pulse width of output Raman pulses and pumping energy is measured. The optical spectra and the pulse waveforms of Raman pulses are analyzed. The relation between the energy of output Raman pulses and pumping energy is measured, and the relation between the conversion efficiency and pumping energy is calculated. When the pumping energy is 42 mJ, the obtained maximum output energy and conversion efficiency of first-Stokes pulse are 10 mJ and 24%, respectively. The wavelength of the first-Stokes pulse of the Raman laser is 1177.6 nm. The typical pulse width the of the first-Stokes pulses is 20 ns.

A new method is proposed for wide-area camera calibration using virtual calibration target created by one infrared light-emittng diode (IR-LED) marker fixed on the moving probe of a coordinate measuring machine (CMM). The camera takes an image when the IR-LED marker moves accurately with the CMM probe to each preset position in turn. Since the measurement space of common CMM is not large enough, the virtual calibration target is imaged in several camera poses to cover the whole measurement volume of the wild-area camera. The calibration parameters are initially obtained by using the 3D information of the virtual target and its image taken from each camera pose. The calibration parameters are finally solved by nonlinear optimization of the intrinsic parameters and the positions and orientations of the virtual calibration target with respect to the camera. The proposed method requires no large-size calibration target and can ensure the calibration accuracy. Experiments demonstrate the superior performance of the proposed method.

In order to study the growth of nanocrystals in solutions, an in-situ real-time optical absorption spectral system is designed and realized. In-situ spectral detection is performed to trace the growth of PbS nano-wires and nano-dots in aqueous solutions. It is found that the addtion of SDS plays an important role in the growth of PbS nanocrystals in preferential directions.

A silicate glass doped PbSe quantum dot (QD) with high concentration is prepared by using a high-temperature melting heat treatment method and taking ZnSe as a precursor of PbSe QD. The transmission electron microscopy (TEM) shows that the QD volume ratio in the glass reaches 2%~4%, which is higher than that of using simple substance Se as a precursor of PbSe. The X-ray diffraction (XRD) measurement shows that the PbSe QD constitute a cubic crystal structure. The measured photoluminescence (PL) spectra shows that the QD glass has strong photoluminescence emission, with full width at half maximum (FWHM) in the range from 1400 nm to 2600 nm. Under the same heat treatment condition, both the PL peak intensity and the FWHM are greater than that of simple substance Se. Instead of Se, ZnSe can avoid vaporization of Se component in high temperature, and be beneficial to crystallization of PbSe QDs in the glass due to the remaining Zn forming ZnO, as a result, QD concentrations in the glass is increased. The PbSe QD glass, with high doping concentration, can be used for preparing IR fiber optical amplifiers with broadband and high gain.

For the precise targeting in inertial confinement fusion (ICF), the requirements for beam transformation, beam shaping and beam control are harsh. The digital control of key technologies online can realize the automatic calibration of the laser system, of which frequency conversion is a crucial part. Based on the reversible algorithm of Fourier transform and Runge-Kutta method without any iterative computation, the inverse problem of type “I+II” KDP frequency conversion is studied in detail on the final optical assemble (FOA) at SG-II upgrade facility. And, some numerical calculation results are also presented. Finally, compared with experimental datas at SG-II upgrade facility, the correction of corresponding theories and the stability of algorithm are verified during the derivation.

An Yb3+-doped lithium silicate glass for multi-graded-index-core fiber is prepared by a two-step melting process. Absorption, emission spectra and fluorescence-lifetime of the samples are measured, and the stimulated emission cross-section σemi of Yb3+2F5/2→2I7/2 transition in samples is calculated by McCumber theory. It is found that σemi of Yb3+ ions in lithium silicate glass at 1006 nm is 0.38×10-20 cm2, and its fluorescence effective line-width is about 82.4 nm, its fluorescence lifetime is 1.31 ms. The Li+-Na+ ion-exchange properties of Yb3+ doped lithium silicate glasses are investigated in molten sodium nitrate at 530 ℃. Imaging properties and radial refractive index profile of gradient index lens made by ytterbium-doped lithium silicate glass before and after central-axis of Yb3+-doped lithium silicate glass rod Li+-Na+-ion-exchanged is studied. Spectral analysis and ion-exchange experimental results show that the glass is an ideal material for production of gradient index laser optical fiber. It can be used for multiple gradient index core fiber. A combination of good lasing and ion-exchange properties enables a new approach to large-mode-area fiber laser.

Three-dimensional photonic crystals (PCs) composed of polystyrene (PS) spheres are fabricated by the self-assembly method, and the transformation of the PC structures from ordered to disordered is carried out via mixing larger silica spheres in the suspension of PS spheres with different concentrations. By measuring and analyzing the tranmission and reflection properties of these samples, the sharp declination of transmittance in the high frequency range, the disappearance of Fabry-Pérot oscillations in the low frequency region, the blue-shift and the gradual disappearance of the photonic band gaps of PCs with the degree of disorder increasing are observed. When the concentration of doped spheres is declined to 0.02%, the lowest transmittance at the center position of photonic band gap decreases from 10% to 1% and the single peak in the reflection spectrum is split into two peaks. These will contribute to the achievement of better transmission extinction of the three-dimensional PCs composed of dielectric spheres along the Γ-L direction as well as to promote their development in the field of new optical devices.

Stereology is an interdisciplinary method for 3D morphological study developed from mathematics and morphology. And it is widely used in medical image analysis and cell-biology studies. The laser scanning confocal microscopic images (LSCMI) of tumor cells are quantitatively analyzed by using stereological point counting method. Three groups of cells, B16F10, B16/Vector and B16/GPR4 cells suspended in culture media, are studied and 20 image sets of each are taken and used in the experiments. The results show that the control group B16/Vector has no significant differences as compared with the parental B16F10 cells, while the experimental group B16/GPR4 shows significant differences in the stereological parameters of the cellular surface area to volume ratio (Rsvc) and the relative cellular form factor (f) (p<0.05 for Rsvc, and p<0.02 for f, respectively), suggesting that B16/GPR4 cells have less surface protrusions and reduced irregularity. This is in line with the previous observations that GPR4 inhibits migration and invasion of tumor cell in the transwell assay. The combination of stereology and laser scanning confocal microscopic imaging techniques provides a quick and useful method in cell biology, and especially in cell morphology studies.

Based on the modified Snyder-Mitchell model the transmission of the optical vortex soliton that is produced by two collinear Laguerre-Gaussian solitons (CLGS) in strongly nonlocal nonlinear media is studied. Under certain condition, the profiles of the optical vortex solitons will rotate in transmiting with the beam width unvarying, which are named rotating vortex solitons, and can be explained by the Gouy phase in superposed light field. A few rotating vortex solitons are shown and the many-ring rotating vortex solitons are accessed in strongly nonlocal nonlinear media.

In order to obtain the incoherently coupled bright-dark photovoltaic spatial soliton pairs that can exist in closed-circuit photorefractive polymer, the propagation of two mutually incoherent optical beams in closed-circuit photorefractive polymer is numerically investigated under steady-state conditions. It is shown that incoherently coupled bright-dark photovoltaic soliton pairs can be established in the photorefractive polymer, in which the mutually incoherent incident beams have the same polarization and wavelength. The bright and dark solitons both can propagate steadily in photovoltaic photorefractive polymer under the conditions of proper parameters or small perturbation. These results provide the theoretical basis for the development of polymer spatial solitons theory.

The surface-profile precision of objective lens for lithography is a key factor which influences the imaging quality. In order to achieve the root-mean-square (RMS) value of lens surface-profile accuracy which is better than 2 nm, a novel lens support structure with multi-points axial flexible support and three-point length-changeable radial holding is proposed, and then structure optimization by the influence of gravity deformation compensation is realized. Finally, the finite element analysis of lens deformation due to gravity and thermal load is done. The results are as follows: for the deformation of lens surface caused by gravity, profile RMS of the upper surface is 0.186 nm, while RMS of the lower surface is 0.15 nm; for the deformation of lens surface caused by thermal load, profile RMS of the upper surface is 0.55 nm, while RMS of the lower surface is 0.54 nm. The results indicate that the lens supporting structure can meet high-precision requirements of surface profile of the objective lens for lithography.

The orthogonal polynomials of two variables are generated on the unit circle and unit square, and a detailed analysis of the free-form fitting precision is carried out using the orthogonal polynomials with three different sampling grids, which are uniformly pseudo-random grid, array grid and circular grid. To ensure the universality of the fitting analysis, many experiments are conducted on rotationally symmetric aspheric surfaces, free-form surfaces and Peaks free-form surfaces. According to the experiments, among the three sampling grids, the array sampling grid is suitable for most fitting situations. XY-polynomial and orthogonal XY-polynomial give better fitting precision than other surface types in most cases on the wave-front fitting, the orthogonal Zernike polynomial has advantage in circle or square domain and orthogonal Chebyshev is the best polynomial when fitting is required on a square domain using the array sampling grid.

A portable fundus camera is designed to make the optical system more simple and compact comparing with the classical system. The photographing system and the focus target projection optical system are using a common focusing lens, so that the focus target projection optical system can be arranged completely in the illumination system. In the focus target projection system a special illumination system is not required any longer, and a focus link mechanism between the projective target and the focusing lens is avoided. Focusing lens fully utillizes the space of the retina object lens system. Taking advantage of narrow bandwidth of light source, observation system and photographing system share the common charge coupled device. A new type of fundus camera is designed with the field of view of 30°, the free working distance of 30 mm. The accommodation ranges between -10 m-1 and +5 m-1. The resolution at the object plane of 45 line/mm across the entire field of view, and the maximum distortion is less than 5%.

Based on the flow-line and simultaneous multiple surfaces (SMS) design method in nonimaging optics, a design method for LED collimator with low divergence angle, good uniformity and high luminous efficiency is presented. The divergence angle ±90° of a Lambertian source is reduced to ±45° by using the compound parabolic concentrator (CPC) reflector, and then the outgoing lights are collimated by the SMS reflector. A theoretical optical ratio is derived from the entendue of the collimator, and top width, top luminous efficiency and top uniformity are introduced to characterize the quality of the collimated lights. The simulation results show that the divergence of the collimator is less than ±2.26°, the total luminous efficiency is up to 0.79, the luminons efficiency error is less than 2.5% compared with theoretical luminons efficiency, the 0.9 top-flat uniformity is more than 0.9, and the top-flat luminous efficiency is about 0.56, it has good results.

Dual-band and multi-band imaging techniques get more and more attention of the national military. As a key part, dual-band optical systems, especially visible light/long-wave infrared (VIS/LWIR) wide-band imaging systems, become the focus of research. The dual-band imaging systems for several major structural forms, including reflective, catadioptric and refraction forms are analysed, and the composition and characteristics of the refraction form are introduced. For the shortcomings of the dual-band system, a VIS/LWIR common-window objective lens in the refraction form used in handheld field is designed. The system′s main technical indicators are: 0.6~0.8 μm (VIS), 8~12 μm (LWIR), VIS=47 mm，IR=58 mm, 2ω=9.8°, FVIS=2, FIR=1.3. Design results meet all the indicators, and the image quality meets the requirements in both bands. The size of the entire optical system is about 51 mm×93 mm×136 mm, which is compact and practical.

In order to diminish the negative temperature effect on image quality of aerial zoom lens, a passive athermal subtraction structure is designed, based on the differential principle. The thermal analysis of zoom lens in working conditions of both high and low temperatures is taken out through NX Nastran finite element analysis software, and the four components are designed by making use of athermal subtraction principle and analytical data. By means of the athermal structural coupling analysis on the zoom lens before and after design, it is proved that the reduction of the maximum athermal distortion of zoom lens is 0.03 mm on the lens after athermal subtraction design. By adopting the Zernike coefficient as the data interface and taking the obtained thermo-structural analysis results as the input of an optical analysis software named Code V, the optical transfer function curve of a zoom lens at +55 ℃ before and after athermal subtraction design is simulated. Compared with the design value of transfer function of the lens, the transfer function value of the lens at 78 lp/mm before the athermal subtraction design is decreased by about 0.2, namely, the transfer function value is reduced by 50%, while the transfer function value of the lens after the athermal subtraction design remains unchanged essentially. The effectiveness of the thermal subtraction design is verified. Finally, the correctness of the simulation result is verified through the experiment.

Fiber-lighting attracts widespread attention because of its advantages of low cost, high safety, good portability and easy decoration. However, the problem of low flux efficiency of coupler products is still difficult to be solved because of the big divergence angle of light sources. In order to improve the efficiency, a coupler based on total reflection theory is designed and fabricated. And according to the results of experiment, the coupler has strong light focusing ability, high coupling efficiency and reduced size. It is a good way to increase the efficiency of light emitting diode (LED)-fiber coupling.

The Kirchhoff diffraction theory is applied to the four-pinhole aperture diffraction screen, so that the intensity, the zero contour of the real and imaginary parts of complex amplitude and the phase distribution in deep Fresnel diffraction region are simulated, and it is found that the bright spots in diffraction field show central symmetric distribution. When the observation plane closes to the diffraction screen, the zero-value points of light intensity can form line segment, on which the eccentricities of the light intensity isoline are close or equal to 1, and the intensity changes very fast on both sides of the zero line of light intensity. The zero contours of the real and imaginary parts of complex amplitude are closed curves. The number of intersection points of the zero contour is even, and positive and negative singularities are equal. Not only the phase around special phase singularities appears symmetric distribution, but also the topological charges of special phase singularities equals zero. With the propagation of the optical wave, the line segment of zero-value intensity changes to be shorter and shorter, finally to be a point.

Four months (January, April, July and October, 2007) of the cloud-aerosol lidar and infrared path finder statellite observations (CALIPSO) lidar 532 nm cloud-free nighttime L1 data (Version 3.01) are used to derive sea surface backscattering coefficient and calculate sea surface mean square wave slope. The collocated AMSR-E sea surface wind speed data are used to calculate air-sea gas transfer velocity at a Schmidt number of 660 using a hybrid model, containing mixed relation between sea surface wind speed with linear, quadratic and cubic terms and gas transfer relocity, proposed by Wanninkhof et al. in 2009. Based on regression analysis, an improved expression for estimating the air-sea gas transfer velocity using satellite lidar measurements is derived and presented. Air-sea gas transfer velocities derived from the CALIPSO lidar data are then compared with that computed from four typical wind speed-transfer velocity relations using the collocated AMSR-E sea surface wind speed data. Global and latitudinal distributions of air-sea gas transfer velocity derived from the four months of CALIPSO lidar data are presented. The results show that the CALIPSO lidar 532 nm single shot data can be used to estimate air-sea gas transfer velocity.

A kind of down-looking synthetic aperture imaging ladar (SAIL) is proposed, with a transmitter of two coaxial counter-deflected polarization-orthogonal beams of spatial parabolic phase difference and a receiver of self-heterodyne detection combined with phase complex-valued processing. In the orthogonal direction of travel, a linear phase modulation proportional to the lateral distance of target point and a quadratic phase history centered in the longitudinal position of target point in the travel direction are collected respectively. The image is focused by the Fourier transform and matched filtering in the two respective directions. Similar to the side-looking SAIL, the suggested down-looking SAIL achieves the fine-resolution, long-distance and two-dimensional imaging with modest aperture diameters, but it has inherent feature that the linear and quadratic phase terms and the size of optical footprint together with their associated imaging resolutions are controllable and variable in a large scale no matter in use or design. And, down-looking SAIL has overcome many difficulties in side-looking SAIL. The down-looking SAIL belongs to optics in the principle and means. This paper gives the general construction of down-looking SAIL, and details mathematically the principle including the data collection and the image processing.

According to three-dimensional (3D) reconstruction theory, based on multi-angle images of the target, 3D points cloud of the target surface is reconstructed. With the method of Delaunay triangulation and the principle of “visibility”, the target surface and the normal vector of surface elements are gained. By the rough surface scattering theory and the target sample bidirectional reflectance distribution function (BRDF), associated with the spectral radiance of the background at some time and place calculated by Modtran, the spectral scattering radiance distribution of the target is obtained by numerical analysis method. Taking a car covered with car sewing as an example, the error of the reconstructed geometric 3D model is 4.11%, and the spectral scattering radiance distributions of the target in three bands are obtained by numerical calculation. The method above can be applied to the research on spectral radiation and scattering of satellites and other spatial targets.

The influence of nonlinear absorption on cross interference correction in multi-gas analysis and modification method when gases are measured simultaneously are studied by non-dispersive infrared (NDIR) technique. The influence of interference coefficient variation caused by nonlinear absorption on system measurement accuracy has been deduced theoretically. The new interference equation modified from the conventional one uses the interference function to quantify the cross interference among the target gases. The interference functions vary proportionally with the nonlinear absorption. They can be obtained by least-squares fitting using the 3-order polynomials. Experiments show that the cross interference is corrected effectively by utilizing the fitted interference function even if the nonlinear absorption still exists in the system.

The thermal stability and irradiation stability of the Mo/Si multilayer in the high temperature and strong radiation environment of the lunar surface are analyzed. The Mo/Si multilayers are measured by hard X-ray diffractometer (XRD) and laser plasma reflectometer (LPR) before and after heating (in a vacuum chamber) at 100 ℃ and 200 ℃. The results show that there is almost no change in the reflectivity and central wavelength of the Mo/Si multilayer. The distribution of the defects and its density in the Mo/Si multilayer is simulated by Mote Carlo method. It shows that the protons and the defects concentrate in the inner of the multilayer with higher energy protons. The Mo/Si multilayers are irradiated by protons with the energy of 60 keV and the dose 3×1012 cm-2 and 3×1014 cm-2 respectively. The erosion defects and nodule defects are observed in the multilayer after irradiation by protons. The results show that the influence on the Mo/Si multilayers is proportional to the dose of the protons with the same energy.

A real-time imaging acquisition and analysis system is designed to investigate thin film growth on transparent substrates using fluorescence microscopy. And eight growth parameters are proposed based on film growth morphological feature. Besides, using home-made experimental system, we analyze the p-6P nanofiber growth on the mica substrate dynamically, revealing the quasi-one-dimensional growth mode of the para-sexipheny (p-6P) molecules on the mica substrate. As an important imaging technique for monitoring thin film growth, the system is expected to play an active role in understanding micro-structural properties of thin film and the interactions between film and substrate.

Polyvinyl alcohol (PVA)/Ag nanocomposite films are successfully prepared. Silver nanoparticles are generated directly in PVA matrix by reduction of metallic precursor silver nitrate (AgNO3) with UV-irradiation. UV-visible spectra of the films show effects of silver ion concentration, irradiation power and irradiation time on preparation of silver nanoparticles. Size and space distribution density of the Ag nanoparticles can be controlled by varing irradiation condition combined with adjusting concentration of Ag+ ion. So the surface plasmon resonance peak of the film can be shifted to 406 nm, matching very well with laser wavelength of 405 nm in optical recording system. Scanning electron microscope (SEM) images show narrow size distribution and uniform, intensive, and relatively independent dispersion of the obtained nanoparticles which is pure silver confirmed by X-ray photoelectron spectroscopy (XPS) analysis. Atomic force microscope (AFM) scans reveal that laser direct write carries out successfully on the films.

Two psychophysical experiments, experiment I and experiment II, were conducted to test color difference calculation method in images. Five ISO SCID images were used as test images and the test image pairs were displayed on EIZO CG 19 monitors. The computed color difference with CIELAB, CIEDE2000, CIE94 and CMC formulae showed that the calculated color difference in lightness and chroma attributes behaved very differently and the color image contents had some effects on the color sensation. An optimization method of color difference formulae is proposed based on the experiment I data. The optimized formulae CIELAB(1.501), CIEDE2000(2.291), CIE94(3.041) and CMC(3.381) perform much better than the original one and CIEDE2000(2.291) is the best among the four. The optimized formulae are also tested by the experiment II data, which proves that the optimized method proposed is accurate, simple and practical.