Chlorophyll a mass concentration will increase when red tide breaks out. It causes the changes of waters inherent optical properties (IOP), such as phytoplankton absorption coefficients and beam total absorption coefficients, which lead to the changes of waters apparent optical properties (AOP). Optical buoy can realize continual observation of apparent optical properties in situ, so it is hopeful to monitor red tide by developing corresponding method based on optical buoy′s data. A semi-analytical monitoring method is developed for red tide by using optical buoy′s data obtained during the process of red tide. First, beam total absorption coefficients are retrieval from diffuse attenuation coefficient and remote sensing reflectance, which are calculated from optical buoy′s data, and combined with experiential underwater downwelling average cosine. Then phytoplankton absorption coefficients and chlorophyll a mass concentration are retrieved. The median relative errors of beam absorption coefficients, phytoplankton absorption coefficients and chlorophyll a mass concentrations estimated by the semi-analytical method are 8.6%, 34.9% and 38.9%, respectively. Compare with quasi-analytical algorithm (QAA) and statistical method, the advantages are that the retrieved results are better and all experiential parameters are from radiative transfer calculation, which don′t depend on buoy′s data and have limited effect on the results.

The boundary layer is very important to human activity as the transition zone between the surface and free atmosphere. Turbulence structure of the boundary layer especially the entrainment layer is an important aspect for the boundary layer research, which is very important to improve understanding of the boundary layer and the research of the boundary layer parameterization. Because of the high level of the top of the boundary layer, it is difficult to detect extensively. Generation and evolution of the atmospheric convective layer are simulated in laboratory convective water tank with the dimension of 150 cm×150 cm×60 cm . When the collimated light beam propagates through the simulated atmospheric convective boundary layer, facula image data can be obtained. Using improved covariance method for power spectrum analysis on the facula image, the peak frequency can be found by finding the maximum power spectral density corresponding to the frequency, which is needed to obtain the peak wavelength as the characteristic scale of eddy. It is found that, in the mixed layer, peak wavelength is small, which means that the mixed layer is homogeneously mixed and small scale dominated there. But in entrainment layer the peak wavelength was larger. The average peak wavelength in the entrainment zone has some relation with the convective Richardson number, and the relation are influenced by surface types and convection condition.

The simulation of the mean flow over airborne laser fairing as well as its aeroptic analysis with selected area electron diffraction software is presented. The simulation reveals that the aero-optic effect with respect to the mean flow field strongly depends on the beam direction: along different beam propagation directions, the root mean square of optical path difference varies between 0.13~1.20 μm, and tilt angle of beam axis varies between 1~12 μrad. Furthermore, the wave-front distortion caused by mean flow-field aeroptic effect is mainly low-order effect: the ratio of tilt to the aberration is about 92%, and the ratio of tilt, defocussing and astigmatism is about 99%. The average of beam quality factor β over all directions caused by no-tilt wave-front aberration is 1.8; when defocussing and astigmatism is corrected, the average of beam quality factor β is 1.16. The beam quality factor β caused by no-tilt aberration increases with the increment of beam radius as a nearly linear manner.

In order to make the simulation of the Fourier telescope imaging system close to reality, the structure of field experimental system is improved. Reflected objects are used, space filters and collimation lenses are replaced by collimation beam-expanders, and large sensitive area charge coupled device is used to monitor imaging. For different cases without atmosphere and with 200 m level atmosphere, 4 objects with different spatial spectra are researched. 9×9, 17×17, 33×33 and 65×65 Fourier components are used for reconstruction. The best angular resolution of imaging is 3.5″. The results indicate that the Strehl ratios of reconstructed images with 200 m level atmosphere are close to those without atmosphere, and then prove that the Fourier telescope imaging system is immune to effects of low-order atmospheric turbulence.

Based on the models of hydrodynamics and radiation transfer, the remote sensing reflectance (Rrs) affected by different water constituents′ vertical distribution under the condition of different wind speeds is simulated. The calibration effect of two different water optical homogeneous functions (Zaneveld and Gordon weight function) in the stratified water mass is compared and analyzed. The results indicate that the Rrs in the range of 500~650 nm is significantly affected by the vertical distribution of suspended particle. With the increasing of suspended particle concentration (5~70 mg/L) at reference depth, the influence of suspended particle matter vertical distribution to the Rrs becomes smaller and smaller (the variation coefficient induced by suspended particle decreases from 27.46% to 3.38%). And the biggest influencing wavelength position on Rrs moves to the long wavelength (585~685 nm). With the increasing of wind speed, the influence of phytoplankton vertical distribution on Rrs in the range of 400~725 nm increases firstly and then decreases. The influence of phytoplankton vertical distribution on Rrs in the range of 400~450 nm is the smallest. The variation coefficient induced by phytoplankton vertical distribution is only 1%. The influence of phytoplankton vertical distribution on Rrs in the range of 500~600nm is the biggest. The variation coefficient induced by phytoplankton vertical distribution can reach 27.18%. The effect of optical homogeneous calibration by the Zaneveld weight function is similar with Gordon weight function when the stratification of water mass is insignificant. However, the effect of optical homogeneous calibration by the Zaneveld weight function is better than Gordon weight function when the stratification of water mass is significant.

During the long-period exposure experiment, the dark current noise of scientific grade change coupled device (CCD) is one of the major noises, the relation of average dark current which is 2.43 ADU/(s·pixel) and 0.4854 ADU/(s·pixel) at -10 ℃ and -20 ℃ and exposure time are tested, respectively. The relation of dark current and temperature is tested. The result shows that the dark current varies with temperature exponentially. As the temporal response characteristics of mechanical shutter have a direct effect on the short time exposure of the CCD, the experiment also shows the relation of exposure time and the average counting of CCD. The result indicates that the mechanical shutter can be fully opened at 18 ms.

Much different from the conventional uncooled infrared imaging technique, a new optical readout uncooled infrared detector based on micro-electro-mechanical system (MEMS) is proposed. This optical readout system employs a knife filter, which has the advantages of high sensitivity, high resolution, and being highly aseismic. However, it is also influenced by various factors such as the radius and roughness of the reflector. According to the experimental validations and the theory of Fraunhofer diffraction, a theoretical model of the optical sensitivity is established, and the influences of various factors (such as the location of the knife filter, the length of the reflector, the radius of the reflector, the roughness of the reflector, the intensity of the LED, the width of the LED) to the optical sensitivity are analyzed. Based on these analyses, an optimization operation to maximize the optical sensitivity is also established.

Under the modulations of on-off keying (OOK), pulse-position modulation (PPM), differential pulse-position modulation (DPPM) and digital pulse interval modulation (DPIM), the intensity superposition coding multiple inpust multiple output (MIMO) optical communication system is compared and analyzed. With the improvement of modulation order, the results demonstrate that the latter three modulations have greater advantage than OOK modulation in the average transmission power, but the corresponding transmission capacity has declined. In the error performance, OOK modulation′s packet error rate is smaller than other three modulations in receiving low power. But when the received power is increased to a certain level, PPM, DPPM and DPIM modulations have the advantage of the 3~10 dB packet error rate to OOK modulation.

Distributed optical fiber sensing system based on Brilouin scattering has attracted wide attention for its ability of sensing the measured field by detecting the continuously distributed information in time and space. Considering the trait of the spectral shape variance during the Brillouin scattering process in optical fiber and the requirement of high accuracy, a novel method based on radial basis function neural (RBFN) networks in which the output layer weights are adjusted by Levenberg-Marquardt method is presented. A model of actual Brillouin spectrum is constructed by Gaussian white noise on the theoretical spectrum, the core frequency is 11.213 GHz and the weight is 4∶1. Comparing the proposed algorithm with traditional back propagation (BP) neural networks, polynomial five times curve fitting and piecewise cubic spline interpolation, the relative error of the new method is 0.0015179% and the temperature error is 0.152 ℃. The appraised parameters are better than other three algorithms at the same test system under different pulse widths and temperatures. The numerical and experimental results show that the RBFN networks is suitable for the fitting of Brillouin scattering spectrum, and the forecast accuracy is improved efficiently.

A dispersion equalizer is designed to compensate dispersions of polarization multiplexing coherent fiber optics communication systems. The proposed equalizer is realized with fraction spaced butterfly finite impulse response (FIR) structure and the corresponding adaptive algorithms are least mean square (LMS) and recursive least squares (RLS), respectively. The residual chromatic dispersion(CD) and polarization mode dispersion (PMD) tolerances of both algorithms are analyzed by simulation. The simulation results show that RLS can compensate 1760 ps/nm residual CD and 104.9 ps differential group delay (DGD) simultaneously and it has 2.23 dB promotion than LMS.

A tunable bandpass microwave photonic filter (MPF) based on multi-wavelength fiber laser (MWFL) which is used as the light source is proposed and demonstrated. The combination of the phase modulator and the dispersion devices convert the phase modulation to intensity modulation in the ordinary single-mode fiber, and it eliminates the low-frequency resonant peak thus a new bandpass filter is realized. By using one of the birefringent fiber loop mirror output windows for the apodization of the multi-wavelength signal, the main lobe to sidelobe suppression ratio of the MPF is raised about 11 dB. The wavelength interval of the MWFL can be adjusted by tuning the polarization controllers (PC) in it. The time delay between adjacent wavelengths is changed when the laser signal passes through the ordinary single-mode fiber because of the dispersion in it thus the central frequency of the band pass MPF is tuned within 7.66 GHz.

Interference cancellation is one of the key technologies in wireless optical code division multiple access (CDMA) systems. The principle and performance of blind multi-user detector algorithm based on recursive least square (RLS) are analyzed, and it is applied to wireless optical CDMA using optical orthogonal code (OOC). The selecting principle of forgetting factor, the convergence and error rate performance caused by forgetting factor are discussed. A RLS blind multi-user detection algorithm is proposed using variable forgetting factor. The forgetting factor is modified. The results show that the system using the improved method can get faster convergence speed and tracking speed of convergence and the estimation error is smaller. The signal to interference ratio is improved from 6 dB of the traditional algorithm to 9 dB. The RLS algorithm with variable forgetting factor is suitable for the wireless optical CDMA system using OOCs, and the performance of tracking the desired user signal is very good.

A mathematical model of the crosstalk in polarization division multiplexing (PDM) system is induced. An adaptive crosstalk elimination scheme is proposed, in which the radio-frequency (RF) power of the optical signal related with the crosstalk is used as feedback signal and particle swarm optimization (PSO) algorithm is applied in the control unit to adjust the polarization controller and eliminate the crosstalk. The effectiveness is demonstrated in 2×50 Gb/s polarization division multiplexing-differential quadrature phase shift keying (PDM-DQPSK) system. The results show that with the crosstalk elimination scheme the performance of the system is improved remarkably and the bit error rate is reduced greatly.

Signal-to-noise-ratio (SNR) is an important index for evaluating multispectral imaging performance. In the early stage of designing a multispectral imager, SNR analysis should be performed for the determination of subsystem parameters. The imaging chain model of multispectral remote sensing is introduced. Characteristics of radiation source, object spectral reflectance, atmospheric radiation transfer, optical imaging, dispersive element, detector spectral responsivity and camera noise are synthesized to come into an end-to-end analysis. A filter array based multispectral imaging system is modeled. Computation of atmospheric radiation transfer is from MODTRAN under conditions of different solar zenith angles and different surface features. The models of charge coupled device are adopted for characterizing the noise features. SNR for different working conditions are shown for the designed multispectral remote sensing system. The SNR analysis is helpful for demonstrating the best operation condition for multispectral remote sensing system of this kind, as well as optimizing related optical system parameters for best performance with lowest cost.

Compressive imaging is a new imaging method based on the compressive sensing theory, which has the advantage of sparse/compressible image reconstruction with far fewer measurements than traditional Nyquist samples. By analyzing the existing Bernoulli and Toeplitz matrix, we propose a novel sparse trinary Toeplitz matrix with random pitch for phase mask. Simulation results show that novel phase mask matrices, comparing with Bernoulli and Bernoulli-Toeplitz phase mask matrices, almost have the same signal-to-noise ratio. But with dramatical reduction of the number of independent random variables and the number of non-zeros entries, the novel matrix is more conducive to data transmission and storage and easy for hardware implementation. Even more, the reconstruction time is only about 21%~66% to that of original matrices.

In the earlier research of reflective tomography laser imaging radar, only the silhouette image of the target rather than the image of the target plane can be reconstructed. An experiment of spotlight mode incoherently synthetic aperture imaging ladar is reported. With this method, the two-dimension image of the target plane is got. In the experiment, the angle-range-intensity data are collected in terms of the rotated side-looking incoherent projections of the target and the image is reconstructed by filtered back-projection algorithm. Computer simulation results is acquired as verification for the image reconstructed from experimental data. As a kind of incoherently synthetic aperture imaging ladar, this system has great practical significance for applications in extensive imaging fields.

The fringe pattern analysis method based on the two-dimensional (2D) analytic wavelet transform (AWT) is proposed for the interference fringe pattern with multi-frequency that occurs in two grating marks in alignment of nanolithography. The multi-frequency of fringe is analysed by the multi-scale of the 2D wavelet transform (WT) first. The separation of the amplitude and phase is processed by the analytic wavelet basis function. The phase correlating to the offset is extracted through the 2D wavelet ridge method finally. The sign ambiguities which always occur in the process of analyzing closed fringe pattern are removed through the discontinuities of the angel in the 2D wavelet ridge. The feasibility of the method is verified by numerical simulation and experiment, and the comparisons of the traditional frequency-based phase analysis method are given. The results show that the noises brought by the fluctuation in the optical path in the fringes can be filtered effectively at the course of acquiring the phase information through the method with good adaptability.

A novel method based on color texture compensation is proposed for three-dimensional (3D) shape measurement of colorful objects. In 3D fringe projection interferometry based on color structured light, color fringe patterns are normally disturbed by the color of the object′s surface. In order to obtain correct fringe order and accurate phase map, a couple of complementary color-encoded fringe patterns are projected onto the surface of object. After decoupling thus the reflectivity matrix of each pixel can be calculated and fringe patterns can be compensated based on the complementary characteristics of the patterns. Wrapped phase map is retrieved through Fourier transform method. Reliable phase unwrapping can be carried out by using the compensated fringe patterns. Experimental results demonstrate the efficiency of the proposed method.

The multi-screen optical method is put forward to solve the problem of three-direction coordinate measurement when the flying projectile gets close to object and explodes in the high altitude. According to experiment characteristic, the demerits of multi-screen across target are pointed out and the technology of using lateral layout area camera to assistant multi-screen across target is studied. The mathematics geometry model on camera, simulating object and multi-screen across target is set up based on projectile burst image acquired by lateral camera. The lateral coordinates calculation method and the modified principle of two-dimensional coordinates of multi-screen across target are studied and analyzed by using projectile flying contrail and its plane coordinates of burst image. The function of three-dimensional projectile burst coordinates is given. The differential method is applied to analyze their coordinate′s errors, which come from the angle of intersection screen, the thick of screen, the measurement time, ranging and so on. Coordinate errors will be less than 40 mm when the height of simulating object is less than 50 m by theoretical analysis and calculation.

In order to measure the stress-induced birefringence and optical homogeneity of fused silica，a method of proportioning refractive index fluid is put forward. Firstly, according to the characteristic of the groups in molecules and molar refraction additivity of the two solutions, formulas for the refractivity of binary solution are analyzed and the technique is given. Secondly, dependence of the refractive index of fluid on different temperatures and wavelengths, is analyzed and verified experimentally. At last, the influence of refractive index fluid precision on test result is analyzed. According to the method, the match precision of the fluid and fused silica can be ±2×10-5; Through the experiment of rough-ground glass, the fluid can improve the transmission from below 20% to above 97% at the wavelength between 450 nm and 700 nm. The fluid which is prepared by the method and the composition we choose, has the characters of low toxicity, no color, no smell, nonvolatile, and its refractivity can remain stable for long. It can be well used for the measurement of the stress induced birefringence and optical homogeneity.

A novel assay detection method for microcystin-LR (MC-LR) in surface water is researched and established which combines surface plasmon resonance (SPR) technique with immunoassay method. SpreetaTM sensor is adopted in the SPR flow injection analysis (FIA) system. The reusable biosensor chip is functionalized with (MC-LR)-BSA using covalent-coupling method. Experimental studies of SPR immunoassay method for MC-LR are carried out, the results show that relative standard deviation (RSD), quantitative range, detective limit and half maximal inhibitory concentration (CI50) are 1.0% (n=6), 2~32 ng/mL, 0.63 ng/mL and 10.7 ng/mL,respectively. Recovery rate of blank sample and different water samples spiked MC-LR ranges from 90% to 113%. It is concluded that tap water does not contain MC-LR while pond water contains 2.46 ng/mL MC-LR in real sample assay. The experimental results demonstrate that the SPR immunoassay can well meet drinking water guidelines of the World Health Organization (WHO) for MC-LR.

Phase-shifting interferometry is widely used in the surface measurement of optical elements as its high precision. The phases obtained from phase-shifting algorithms are wrapped between -π and π. The algorithm based on the region growing theory (seed point algorithm) can realize phase unwrapping of connected regions with high precision. The algorithm based on discrete cosine transform (DCT) algorithm can realize phase unwrapping of rectangular region. In practical measurements, the valid region of test flat is often non-rectangular and separated. On the basis of analyzing the advantages and disadvantages of the above algorithms, the seed point unwrapping algorithm based on DCT algorithm is presented. Firstly, the wrapped phases are unwrapped totally with DCT algorithm. Secondly, the wrapped phases of separated regions are unwrapped with the seed point algorithm respectively. Then they are unified with the interference orders obtained from DCT algorithm. The experimental results show that the algorithm overcomes the disadvantages of the seed point algorithm and DCT algorithm. It can unwrap the wrapped phases obtained from separated interferograms correctly and quickly, and it is more stable and more precise than the two algorithms above.

Radiometric calibration in-flight is one of critical techniques for information quantification of optical remote sensing. With the development of quantitative application of high spatial resolution satellite optical sensors, required precision on absolute radiometric calibration is asked higher and higher. A calibration method based on gray-scale tarps is presented. The measured ratio of diffusion to global irradiance substitutes the aerosol scatter computed by radiance transfer code. Besides high reflectance tarps are deployed to improve the accuracy of on-orbit radiometric calibration. Preliminary results show that in-flight absolute radiometric calibration using gray-scale tarps for high spatial resolution satellite sensors less depends on model assumption and could achieve high precision calibration at full dynamic range. The uncertainty is less than 4% and this approach can also satisfy the application demand to the complex environment.

A photonic-crystal coupled waveguide is proposed by introducing two line-defects to perfect triangular lattice. By analyzing the dependence of band shape on various structure parameteral, unique band with approximate zero group velocity can be obtained in an optimized photonic-crystal coupled waveguide. Moreover, by chirping the widths of the photonic-crystal waveguides in the optimized structure, a perfect wideband slow light is obtained, it possesses the bandwidth of 13.24 nm and the average group index of 28, which is verified by means of two-dimensional finite-difference time-domain (FDTD) simulations, and our numerical analysis shows that Gaussian pulses passing through the coupled waveguide have a relative temporal spreading below 10%.

The gain calculation of a whispering-gallery-mode fiber laser pumped by an evanescent wave involves in the distribution function of incident angle on the inner surface of the fiber, and the numerical calculation. Based on the ray-optic theory, the distribution function of incident angle on the inner surface of the fiber is derived as the beams of Gaussian distribution and beams of homogeneous distribution are tightly focused via a concave lens and coupled into an optical fiber. Distribution function is caculated by using the method of composite Simpson integral formula, and the gain property of a whispering-gallery-mode fiber laser has been successfully investigated as the pump light propagates along the inner surface of the fiber via frustrated total internal reflection. The calculated results have reference values for the theoretical and experimental studies for this kind of fiber lasers.

Based on the predecessor′s theoretical achievements, probabilistic analysis for realizing terahertz (THz) radiation of lasers by strict calculation method is given. The distributions of conduction subband structure and the electron wave function of GaN-based three-level quantum cascade lasers are solved with the transfer matrix method by Matlab, the polarization field of material is analyzed detailedly. The relationships among dipole matrix element, applied external electric field, the barrier layer of Al composition and energy difference of conduction subband in near-resonant conditions are calculated, and their effects on properties of lasers are studied. The analysis of the results shows that realizing stimulated radiation is very strict, it is proper that the composition of Al is 0.15 or 0.16, and the external electric field intensity is greater than 63 kV/cm，but is not too large. In this case, the near-resonant conditions can be satisfied, so that population inversion is realized to reach THz quantum cascade lasing. While the largest dipole matrix element is obtained at the composition of Al of 0.15 and the external electric field intensity of 69.0 kV/cm, indicating that transition probability is also the largest. It is beneficial for the properties of lasers, thus the preferable active region can be constructed for quantum cascade lasers.

A relatively simple model is developed to simulate the widely tunable double-ring resonator lasers. In the simulation, the active region of the device is modeled using conventional time domain traveling method, because when the tuning range is large than 40 nm, the gain shape should be considered. The passive parts are first modeled by frequency domain method and then transformed into time domain via digital filter. The simulation result shows that the coupling coefficient has a significant effect on large signal modulation. With low coupling coefficient the laser can get narrow linewidth but poor modulation performance. Finally, the switching characteristics such as switching delay and multi-mode competition are also investigated. The result shows that the laser can switch the wavelength with high speed and large range.

Eu2+-Dy3+ co-doped silicates glass was prepared by high temperature melting under reducing atmosphere. And the Eu2+-Dy 3+ co-doped SrSiO3 transparent glass ceramics are obtained after heat treatment. The samples′ excitation spectrum and emission spectrum are measured. The glass ceramics′ luminescence properties with different amount of substance ratio of Eu2+-Dy3+ are studied, and the corresponding chromaticity coordinates are calculated. A broad emission band region in 400~550 nm(green light) due to the 5d→4f transitions of Eu2+ is observed, as well as several sharp emission peaks at 483 nm (blue light) and 575 nm (yellow light) due to the 4F9/2→6H15/2 and 4F9/2→6H13/2 transitions of Dy3+. The ultraviolet light-emitting diode (UV-LED) excitable glass ceramics emitting white light are obtained by controlling the amount of substance ratio of Eu2+-Dy3+. When the amount of substance ratio of Eu2+-Dy3+ is 1∶8, the Eu2+-Dy3+ co-doped glass ceramics get the optimal white light emission and the corresponding chromaticity coordinate (0.268,0.356) exactly falls into the white light area of the CIE-1931 chromaticity diagram. The results indicate that the Eu2+-Dy3+ co-doped SrSiO3 transparent glass ceramics can be used as a potential matrix material for white light emitting diode.

A new fluorene-based derivative with long conjugated structure is synthesized by the Heck reaction. The ultraviolet absorption and fluorescence spectrum are measured in four different polar solvents (petroleum ether, methylen echloride, ethyl acetate, DMF). The results show that the solvent polarity has certain effect on the UV absorption and fluorescence spectrum of the new compound, in certain details, the UV absorption and fluorescence spectrum red shift occurs with the increase of solvent polarity. Picosecond pulse laser whose excitation wavelength is 1064 nm is used to investigate the optical limiting of the new material. The experimental results show that the new material has a large three-photon absorption coefficient (γ=5.4×10-21 cm3/W2) and the three-photon absorption cross section 3=7.3×10-77 cm6·s2.

High resolution melting curves analysis (HRM) is a recently developed powerful technique for the detection of gene mutations and SNP analysis. Monitoring the changes in fluorescence from saturated dye labeled on dsDNA, as a PCR products (amplicons) are melted, the minor difference of nucleic acid sequence can be discriminated. Here fast fluorescence detection system based on fiber-optics switch array is designed for fulfilling the requirements of speed and sensitivity. High-density fluorescence data are processed by a series of procedure, such as smoothed, automatic baseline detection, normalizing and differential to temperature, different gene types could be recognized quickly and correctly by the high resolution melting curves.

A new method of depth resolved dispersion compensation to enhance the axial resolution in Fourier-domain optical coherence tomography is proposed. In this method dispersion of light over whole imaging depth range is compensated accurately with depth-resolved dispersion coefficients which are obtained by windowed Fourier transform of spectral interferogram. The proposed method can simultaneously compensate broadening and distortion of point spread function in different imaging depth compared to traditional dispersion compensation method where over and lack of dispersion compensation arise because a uniform dispersion coefficient is used. Results of computer simulation and experiments indicate that the proposed method can make a good dispersion compensation and improve axial resolution through the whole imaging depth of Fourier domain optical coherence tomography.

In order to carry out the goal of highly sensitive, fast and accurate detection and identification of pathogen, a novel method for highly sensitive and fast detecting trace amount of nucleic acid sample is introduced. A microfluidic chip isothermal DNA amplification for bacteria molecular diagnostics is developed. New micro-nanoliter reaction assay chip is manufactured, and the surface inertia processing technique of chip is advanced to drop the chip surface adsorption to DNA molecules. A portable confocal detector with high numerical aperture and long working distance is built to reduce background fluorescence and improve the sensitivity. The sensitivity of 5 DNA copies in micro-nanoliter reaction assay is obtained. The method and detector was verified by Escherichia coli identification to acute respiratory disease, and can meet the application of low-cost detection of clinic medicine.

In order to improve the computational speed and prior background noise-dependent problem of single molecule localization algorithm, a Fourier domain localization scheme based on zero-padded fast Fourier transform and phase gradient operators is used to obtain a powerful mathematical model for localizing a single molecule without numerical fitting. Numerical simulations indicate that the proposed method exhibits nanometer scale localization precision while executing almost as fast as the fluoroBancroft algorithm. Furthermore, a sample consisted of several lines of molecules are simulated imaged. The results demonstrate that two lines of molecules separated by 30 nm can be resolved. Finally, super-resolution images of filopodia in HeLa cells are reconstructed based on the method, in which filopodia with diameter of 75~200 nm are resolved.

Based on vectorial diffraction theory, an analytical integral representation to calculate the field gradient of focused electromagnetic fields is derived by use of the differential recursion formula of the Bessel functions with different order. Within the phenomenological model for second harmonic generation (SHG) of centrosymmetric material, second harmonic (SH) generation of single centrosymmetric spherical particle excited by a focused beam is investigated. With increasing numerical aperture, the SH radiation distributions of the surface and bulk responses are compared and discussed in term of the properties of the intensity and gradient distributions of the focused field. The results indicate that the influence of the variation of the focused field on the bulk response is more remarkable.

In order to obtain analytic theory of 1D photonic crystal, multi beam interference theory is used. Analytical formulas of total reflection tunnel effect frequency of 1D photonic crystal is deduced. Physical mechanism of total reflection tunnel effect of 1D photonic crystal is explained. Using the analytical formulas change rule of total reflection tunnel effect that response curves of frequency versus cycle number and incident angle and optical thickness are studied. Transmission matrix method and analytical method is compared and their results are the same, which indicates that analytical method is the right way. Analytical theory to analyze variable relation is convenient, it makes up deficiency of numerical calculation method of 1D photonic crystal.

We investigate systematically two-color holographic recording properties such as the saturated diffraction efficiency and recording sensitivity in the near-stoichiometric LiNbO3 crystals with different dopants and oxidation-reduction (O-R) states. In the two-color recording experiment, the volume holographic gratings is recorded by red light, simultaneously sensitized by violet light. The results show that the saturated diffraction efficiency increases and later decreases with the increase of the ratio of recording light intensity to sensitizing beam intensity, but the sensitivity decreases gradually. Higher Tb-doping density makes higher diffraction efficiency but lower sensitivity when the Mn-doping density keeps the same. Crystal doping with Mn makes higher sensitivity but lower diffraction efficiency when the Tb-doping density keeps the same. The saturated diffraction efficiency and recording sensitivity of the reduction crystal are higher than those of the oxidation crystal. The saturated diffraction efficiency and sensitivity depend on the ratio of recording light intensity to sensitizing beam intensity, the doping concentration and the O-R state. An optimization may be obtained by further modifying these conditions appropriately.

A Schmidt optical system consists of a Schmidt corrector plate and a spherical primary mirror, in which the corrector plate lies at the center of the spherical mirror. The focus of the system is not necessarily coincident with the one of the mirror. To precisely find the initial surface parameters of the corrector, a mathematical model based on wavefront aberration functions with the corrector plate surface varying as a function of defocusing amount is established. This model simultaneously corrects both the third-order and the 5th-order spherical aberrations for the system. A Schmidt optical system with aperture size 1000 mm, the mirror radius of curvature 2000 mm and the F number 1 is designed as an example to analyze and test the correctness of the mathematical model of the corrector. The results show that the mathematical model for the corrector agrees with the optimized result of the optical design software Zemax very well. The initial parameters of the optical system are improved greatly. It provided the theoretical foundation of the Schmidt optical systems design with the large aperture and the large relative aperture.

A new method that the target plance is uniformly illuminated with aspheric lens is proposed. Based on the energy conservation law, it can be figured out the angle between the light source and the target surface, and the macro language of Zemax is used to make the lens meet the above mentioned relation, simulating and optimizing the result in the non-sequential mode and respectively simulating the three cases of the front surface. It is proposed and simulated a spherical LED array, and analysised the effect of the illumination uniformity of the angle and distance offsets . The result shows that the uniform illumination in a distance of 1 m and 0.25 m in diameter of the plane is achieved, with the uniformity of 96% or more. The spherical array meets the application requirements of shadowless lighting and the depth of illumination up to 1 m.

The need for developing miniature, portable and wide spectral covering spectrometers is urgent with the increase of field analysis experiment. A miniature wide-waveband monochromator which is comprised of three concave holographic gratings and two flat bedplates are designed based on the root-mean-square merit function. The three concave gratings are fixed on the upper flat bedplate symmetrically which is rotated by a stepper motor to switch the gratings and the other stepper motor is used to rotate the lower flat bedplate to realize the scanning movement. The response wavelength ranges of the three gratings are 400~1000, 1000~1700 and 1700~2500 nm with their corresponding theoretic resolution limit better than 2.5, 2.8 and 4.0 nm respectively. Manufacture errors, fixing errors and errors of the grating-switching flat bedplates are well analyzed for the three gratings. All the results show that within the error bounds the monochromator′s spectral quality can satisfy the demands of the outdoor infrared spectrum analysis very well.

From the view of balancing the contrast of two imaging optical paths, a practical mini-optical engine of liquid crystal on silicon (LCoS) stereoscopic projector is designed. The engine is composed of two LCoS panels to modulate the left and right images respectively, with a white LED as light source and two standard MacNeille polarization beam splitter (PBS) to generate two linear polarized beams with orthogonal polarized state. The whole optical engine has a simple design and compact structure with the size of 105 mm×28 mm×25 mm. Actual parameters of every part in our optical engine are measured. Based on these values, the calculated contrast and the light efficiencies of the right and left eye paths are 641 and 3.61% respectively, and the total light flux is about 20 lm.

A special illuminating system is proposed and designed in order to accurately test convex off-axis aspherical mirrors with computer-generated holograms (CGH). Illuminating system is used as reference system and used to project testing beam on under-testing aspherical mirrors vertically and also makes testing beam and reference beam near common-path. The geometrical system of this illuminating system is introduced and analysed. Then the relation of characters of work distance, focal length and the curvature radius of reference surface of illuminating system is obtained after simplify this multipurpose system to simple model system. The initial system can be realized by controlling these characteristic parameters as merit function during optical design process. Design results show that this method can satisfy requirement of system use.

The optical properties of the Fourier transform spectrometer such as the size of source, the ununiformity of the intensity and the aberration of the optical system are analysed. It is shown that the large size of source caused the double peaks and lower spectral resolution, the ununiformity and the aberration cause the noises on the base line. The numerical results show that the noises can be ignored as the size of source at the stop is smaller than 2.5 mm, the standard deviation of intensity is smaller than 0.5, the root-mean square (RMS) of wavefront aberration for the collimating lens is smaller than 0.05 waves, and the RMS of spot diameter for constricted lens is smaller than 30 μm. The design of optical systems is proposed.

Cooling IR focal plane system is paraxially analysed with the optical invariant and first order parameters are proposed which quantify the concentrition and variation of narcissus on focal plane arrays (FPA). The ralation between NITD and parameters of environment and system is summarized based on the theory of thermal-radiation theory. The narcissus of an optical design in 3~5 μm with F-number 2.75, view angle 4° and effective focal length 90 mm is caculated and optimised through controlling its first parameters and using real ray trace as confirmation in CODE V, after which the narcissus effect drops by 70%. The distribution of narcissus is simulated on practical conditions in ASAP and the results are presented, it is shown that the NITD dropped down below the preset value after optimization and the narcissus is controlled effectively.

Optical waveguide has a promising application as absorption cell in concentration measurement for gases and liquids. Hollow fiber has many advantages when it is used as the absorption cell for spectroscopic gas sensing. The characteristics of the sensing system are directly related to various parameters of the hollow fiber. A mathematical model is proposed considering both the transmission loss of the hollow fiber and the signal-to-noise ratio of the system. Theoretical analysis is made for the dependence of the output intensity and sensitivity on the fiber parameters such as length and inner-diameter, the concentration of target gas, as well as the intensity distribution of light source. Several important results are obtained from the simulation, which provide optimizing methods for the sensing system and algorithms for error compensation.

The coupled mode theory of parallel photonic crystal resonators is analyzed, based on which, a side-coupled waveguide to achieve the efficient coupling between photonic crystal devices and the light source is proposed. The theory analysis indicates that the coupling efficiency is sensitive to the total number, the interval and the quality factors of the resonators. By the optimization of the coupling efficiency and the coupling region, five parallel resonators are selected to construct the coupling part of the single channel side-coupled waveguide. Single channel propagation of the side coupled waveguide is realized through changing the interval of the resonators. The single channel side-coupled waveguide achieves the coupling efficiency of 94.49% at the wavelength of 1.55 μm.

The shape of trap-pit strongly affects the reflective characters of multi-crystalline silicon (mc-Si) surface. Using Fourier transform, a model how the trap-pit shape affects the textured surface reflectance is investigated, and a simple expression for calculation of the etched surface reflectance is given. The theoretical analysis shows the strong dependence of reflectance on the textured shape and the trap-pit density. It is found that the reflectance is low for the etched surface covered with U-deep trap pit, but it is high for the etched surface full of V-shallow trap-pit. In experiments, mc-Si was textured in the acid solution with different concentration, sample′s surface was scanned by SEM and the reflection spectrum was measured in the 350~1100 nm wavelength range. The experimental results fit the theoretical analysis well.

Two identical cavities, each containing one two-level atom, coupled via a two-photon hopping interaction are considered. The evolution of the state vector of the system is given. Negativity is used to quantify the degree of entanglement. By means of numerical calculations, the temporal evolution in the entanglement between atoms, between cavities, as well as between the atom and the local cavity mode are investigated. The influence of cavity-cavity coupling coefficient on the entanglement is also discussed. The results show that the entanglement between atoms is strengthened, and that between cavities and that between the atom and the local cavity mode are weakened with the increase of cavity-cavity coupling coefficient.

By modifying five-parameter semiempirical model of bidirectional reflectance distribution function (BRDF) and absorbing the advantages of other models, a six-parameter model of BRDF is proposed. The model, with simpler expression and better fitting effect, satisfies both reciprocity and energy conservation properties of BRDF, which enables the model to be practical. Simulated annealing algorithm is carried out on the statistical modeling of the BRDF of different samples, the corresponding model parameter values and deviation are obtained, the results verify the correctness of the model. According to the samples with weak scattering, which is especially suitable for this model, the diffuse component of the model has better fitting effect than that of the five-parameter model, and its total accuracy is slightly higher than that of the five-parameter model. Finally, to show the BRDF of the target samples visually, three-dimensional BRDF maps at differently incident angles are given.

The even-parity highly excited states of europium (Eu) atom have been investigated with resonant excitation and electric field ionization (EFI) method. Among the 89 states detected, the information about level energy and spectral assignment of 56 states have not been reported previously. A combination of analysis of their effective principal quantum numbers, quantum defects, and the comparison with literature, enable us to classify them as the 4f76s (9S) np (8PJ or 10PJ) Rydberg series, which fills the gap in previous literature for the n=19~39 states of the series. Besides, the ionization limit of Eu atom is suggested to be at 45734.2 cm-1, near which the existence of a broad pedestal is also explained.

To prepare aluminium coating with high performance in the spectral range of 130~210 nm, the thicknesses of Al and protective MgF2 layers are theoretically optimized and the optimum thicknesses are determined to be approximately 80 nm and 33 nm, respectively. Experimentally, MgF2 protected Al coating is prepared on a BK7 substrate using thermal-boat evaporation. The reflectance of the prepared Al coating is measured to be higher than 80% in the spectral range of 130~210 nm. The effects of deposition rate of Al and UV irradiation treatment on the spectral performance of the Al coating are studied. Aging effect is also experimentally investigated. The results show that the higer deposition rate of Al, the higher reflectance of the mirror. Correct storage method can maintain the spectral performance of the Al reflective film over time. Proper UV irradiation treatment can also enhance the reflectance of Al coating in the vacuum ultraviolet spectral range.

Metal grating models are designed to correspond the extraordinary transmission, structures with single slit and periodic slits and structures with different widths and different periods are calculated by finite difference time domain (FDTD) method. It is found that grooves on a metal grating play a negative role to energy transfer on the metal surface. Frequency domain of transmission becomes wider in pace with the width of the film; with the increasing of the width of the slit, the distribution envelope tends to flat, the side of shorter wavelength of the main transmission peak is essentially the same, while the distribution curve of the main transmission peaks and the side of longer wavelength of it become wider. It indicates that the width of the slits impacts the resonance modes of surface and the distribution of transmission. The transmission of single slit compared to the periodic structure′s, we found that transmittance curves almost coincide. It shows that the surface modes do not depend on the slits and there is no interaction between them.