In view of the large area of dead zone caused by the surface quenching and the contradiction between the dynamic range and the detection efficiency. By applying the epitaxial resistance quenching technology, the quenching resistance was prepared by using a substrate epitaxial layer of silicon material connected with the Avalanche Photo Diode (APD) unit. The developed Silicon Photomultiplier (SiPM) with the active area of 1×1mm2 is called F5-2 which micro cell size is 7 μm and the density of the micro element is as high as 21 488 cells/mm2. The breakdown voltage is 24.5 V; the leakage current is on 10 pA; the gain is 1.4×105; the dark count rate is about 600 kHz/mm2 and the crosstalk rate is about 10% at room temperature over bias 2.5 V; the dynamic range is about 1.8×104 cells/ mm2 and the Photon Detection Efficiency (PDE) peak value @480 nm is 16%; the recovery time is about 8.5 ns. The device has good characteristics of photon counting on account of the better single photon resolution ability. Moreover it can detect photons at the liquid nitrogen temperature which has a great potential for expanding SiPM applications such as dark matter measurements at very low temperatures.

The influence of preset condition and the two electrons transport on the noise of the quantum dot infrared photodetectors was calculated and simulated, which was based on the noise model including the influence of the electric field on the drift velocity of electrons, moreover, with account taken of the dependence of the activation energy on the microscale and the nanoscale electron transport. The results show that the noise model has a good agreement with the experimental data at 25~45kV/cm electric field. The noise increases with the electric field and temperature, the noise increases rapidly below 80K, but it increases slowly above 80K, and when the temperature is lower, the change of the noise is more obvious with the change of the electric field. The noise does not change along with the change of the activation energy under the microscale electron transport, decreases with increasing the activation energy under the nanoscale electron transport, and increases with increasing the change rate of the activation energy under the nanoscale electron transport. The research can guide the design and improve the performance of the quantum dot infrared photodetectors.

The technologies of fabricating polymer photonics crystal fiber to suit the application needs of terahertz transmission were studied, which were related to material selecting, fiber preform fabrication and fiber drawing. According to the analyzation of optical polymers’ properties and the experimental verification, ZEONEX has low absorption of less than 3 cm－1 in Terahertz waves, low water absorption of less than 0.01%, high glass transition tempreture and decomposition temperature of 136℃ and 420℃ respectively. As for fiber preform fabrication and drawing, the model system was improved based on injection moulding, and drawing technology of Pascal level pressure auto-control was initially invented. The controlled value oscillations is no more than 1.5 Pa in the range of 10~200 Pa. Therefore the preform quality and reliability are promoted and fiber microstructure is effectively controlled. With the proposed technology it is hopeful of producing high air filling factor polymer photonics crystal fiber.

A spot detection method was proposed for acquisition, pointing and tracking system in the case of azimuth offset and pitch errors exist at the same time. The position error between the broken spot and the Gaussian complete spot was analyzed. The problem was solved when the beam was drifted and the incident beam was not parallel to the line of sight of the antenna and the four-quadrant detector could not be detected separately. In the end,conduct experiments to verify the validity of approaches.The improvement of detection precision is also presented.

A temperature and glucose solution concentration sensor based on intrinsic evanescent wave was proposed and fabricated. By studying on the relationship between the thickness of etched fiber coating and the output spectrum, the suitable etching thickness was determined. The cladding of a standard single-mode optical fiber was etched to 2.4 μm, and the temperature and glucose solution concentration sensing were realized by measuring the variation of output optical power, because optical fiber evanescent wave is extremely sensitive to the change of external medium. The experimental results show that the sensor has temperature sensitivity of 9.58×10－3 dBm/°C at the range of 10~70 °C with linearity as high as 99.36% and glucose solution concentration sensitivity of 0.126 dBm/(g/L) at the concentration range of 0~3% with linearity of 97.95%. The response time of the sensor is less than 30 s. The sensor has advantages of simple operation, high accuracy, good reproducibility and wide application range, thus has potential application value.

To further increase the detection distance of optical fiber array, a prototype of 32-element distributed feedback fiber laser hydrophone towed line array with a diameter of 16 mm is developed. The acoustic pressure sensitivity of the element reaches to －142.7 dB with the fluctuation less than ±2 dB in a frequency range of 10~2 000 Hz. Based on the time division, wavelength division multiplexing technology and acoustic optic modulator, 32-element fiber laser hydrophone array multiplexing is realized. The crosstalk between each element and each channel are both less than －40 dB. The static and dynamic towed tests on the lake are completed. The distributed feedback fiber laser hydrophone towed line array can form stable beam pointing to the target in both the static and dynamic towed state of 6～16 knots, which is the same as the GPS record. The application prospect in engineering of the distributed feedback fiber laser hydrophone towed line array is demonstrated.

The full characteristics cannot be obtained by single filter in spatial information extraction of hyperspectral image. Combining bilateral filter and domain transform filter of normalized convolution, an improved algorithm of classification was proposed. The method advanced an adaptive fusion of spatial information for classification optimization. Firstly, bands of hyperspectral image were sampled into two groups. Secondly, spatial information of the two group images was extracted by the bilateral filter and the normalized convolution respectively. finally, the two kinds of spatial information were combined and classified by support vector machine. The experiments show that the algorithm is better than original support vector machine with the pure spectrum information, dimensionality reduction, the spatial-spectral information, and the method of edge-preserving filtering and recursive filtering. the performance of hyperspectral image classification algorithm is greatly improved, although training samples were only 5% and 3%, the verall accuracy of Indian and Pavia can reach 96.95% and 97.89% respectively, with 2%~13% higher than other algorithms, and the effectiveness of the method is fully verified.

Fourier and Wavelet domain based on deconvolution algorithm has a massive superiority over others when the noise level of blurred image is low. However, this kind of method will lead to a bad result when the blurred image is noisy. In this paper, to solve this problem, two constrained terms were introduced into Fourier domain filter and Wavelet domain filter correspondingly. In Fourier domain, the objective function was performed in a matric form and was added with Laplacian regularization. The parameter of this regularization term was computed from the noise power and the power of high frequencies. Similarly, the objective function in Wavelet domain was equipped with power constrain and the parameter of power constrain term was a function of the parameter of Laplacian regularization term. The Laplacian regularization term reduced the power of error caused by Fourier domain and the power constrain enhanced the anti-noise ability of Wavelet domain filter. Experiments showed that the improved algorithm led to a better results with stronger robustness. The peak signal to noise ratio of the improved algorithm was averagely 1 more than the number of initial algorithm, when the standard deviation of noise ranged from 0.01 to 0.1. And the robustness to point spread function was shown. Even when the variance of Gaussian point spread function deviated about 0.4 away from the ground truth, the peak signal to noise ratio of the improved algorithm was higher than the number of initial algorithm.

The Causal Real-time Relationship Reed-X Detector (CR-R-RXD) detecting algorithm based on the pixel-by-pixel processing for hyperspectral imagery, which has the problems of a large amount of computation, a long display time and a slow running speed. A CR-R-RXD detecting algorithm based on line by line was proposed in this paper. Compared with the CR-R-RXD method based on pixel by pixel processing, the whole row pixel vector of hyperspectral image was used as input in this proposed method. That is, dealing with a row of hyperspectral data needs to be calculated only once, which greatly reduces the calculation times. Experimental results show that, to compare with the R-RXD algorithm and CR-R-RXD method based on pixel by pixel processing, the proposed algorithm can achieve the process of fast real-time processing with almost the same accuracy as the R-RXD algorithm, the detection accuracy is improved to compare with the CR-R-RXD algorithm based on pixel by pixel processing, and the testing time of the algorithm is reduced, which enhances the timeliness of the algorithm.

With the emergence of counter-stains, a multi-spectral imaging method based on the multi-channel narrow-band filter and color image sensor was proposed in this paper. Firstly, a multi-channel narrow-band filter was used to separate the light source. Then, the multi-spectral stripping model was established by using the multiple linear regression method to separate the monochromatic light aliasing response from the color image sensor. The multi-spectral image is real-time delaminated and output by FPGA(Field Programmable Gate Array). The experimental results show that, the Full Width at Half Maximum(FWHM) of the multi-channel narrow-band filter is 12 nm/15 nm/20 nm, and the transmission light is really a narrow-band monochromatic light in three different wavelengths; the model has high accuracy when the test level is 0.01; the substance with the same spectral characteristics has a consistent feature on the same band grayscale image and the same substance has an obvious different feature on different bands grayscale image.

In order to improve the image consistency, the factors influencing the image consistency was analyzed according to the principle of aperture-divided and amplitude divided method. In addition, one approach for improving the image consistency based on the fiber optics imaging was presented. Taking the six-frame divided by the pyramid as an example, the influences of the thickness, core diameter of fiber face plate and incident angle on image consistency were simulated by Lighttools. The results show that energy difference of the six image planes could be less than 0.3% with increasing of the thickness or decreasing of the core diameter of the fiber, when the incident angle ranges from 15 ° to －15 °.Based on the fiber optics imaging, the optical frame-divided structure by the pyramid can effectively improve the image consistency of framing camera.

In order to achieve the real-time calculating about the flight trajectories of the multiple targets and guiding the equipment to track the targets, a real-time multi-target intersection method was proposed. Such method is based on the characteristic of target movement and the inherent characteristic of optic-electronic theodolite tracking measurement. This algorithm can achieve the goals of sorting homologous measurement data and eliminating the false target trajectory, and finally get the true target trajectory. The algorithm is applied to the optic-electronic theodolite measuring system which is under the condition of target N≤3 and communication cycle being 50ms. The experiment results show that the method can guide the measuring equipment to track accurately, stably and in real time.

Spectrally encoded imaging uses a diffraction grating and a spectrum analyzer setup to obtain microscopic images. The different position on the sample is illuminated by different wavelength. Then the reflection light is decoded to obtain spatial information. In this letter, a spectrally encoded microscopy is described which is based on a super luminescent diode source and a home-built spectrometer. By imaging a 1951 USAF resolution target, the measured lateral resolutions were found to be 1.72±0.13 μm and 1.26±0.08 μm in the spectral and its vertical directions, respectively. The axial resolutions along the different lateral positions were measured to be unequal. The images of excised swine liver tissue were obtained at different locations. The veins, liver sinusoidal endothelial cells and hepatocytes can be visualized. The Chicken heart tissue was imaged at 10 μm per step along the depth direction beneath the surface, the images indicated the difference in the structure features at different depths. The results demonstrate high resolution, depth-resolved imaging capability by this method.

Small-scale roughness on surface is equivalent to a multilayer structure with same thickness and gradient refractive index. By using characteristic matrixes, the reflectivity of P waves of the effective multilayer model with different incident angle is calculated; the refractive index of the absorbing medium is a complex number in the calculation of Fresnel formula; COMSOL Mutiphysics is used to model and simulat the small-scale roughness and absorption. The calculation results show that both the small-scale roughness and absorption of the dielectrics can make errors in measurement of the refractive index. In conclusion, in order to get the precision of 10－5 , the refractive index of rough dielectrics should be measured by critical-angle technique, while it is better to measure absorbing dielectrics by Brewster-angle technique.

A multi-feature parameter neural network analysis technique based on terahertz nondestructive testing for the analysis of the adhesion quality of the heat-resistant composites was proposed. A film (thickness is 0.1mm) extraction method was put forward to simulate the bonding defect of the heat-resistant composites. The terahertz time-domain spectroscopy nondestructive testing technology was used to detect the multilayer high temperature resistant composite bonding defects. Compared the similarities and differences of terahertz time-domain and the frequency domain information between the upper debond defect and the lower debond defect, the multi characteristic parameters were proposed for the adhesive quality, such as upper debond parameter, lower debond parameter and centroid absorption parameter for frequency domain. The characteristic parameters were optimized as the input of back propagation neural network to recognize the upper and the lower debond defects. Based on the back propagation neural network training test, the identification was realized for the 0.1mm thickness upper debond defect and the 0.1mm thickness lower debond defect.

To overcome the restrictions of long calibration time, high cost and poor maneuverability for radiometric calibration of the ground-based infrared radiometric measurement systems with large aperture, a radiometric calibration method, which is based on low-temperature area blackbody, for infrared systems with high dynamic range was proposed. First of all, the neutral-density filter in the system was measured to obtain its actual transmissivity and calculate its radiance. Secondly, the radiometric calibration was performed using low-temperature blackbody at two integration times. The response and stray radiation of the system as well as the bias of the detector were obtained on the basis of the calibration results. Then, the calibration results at high dynamic range could be acquired by extrapolating the low-temperature calibration results, combined with the measured characteristics of the neutral-density filter. To verify the effectiveness of the proposed method, a Φ600mm infrared system was calibrated at high dynamic range, using the proposed method and the typical method of high-temperature blackbody and large aperture collimator. The experimental results indicate that the error of the proposed method is less than 10.25%, which means the proposed method can be used to perform calibration for the system. The radiometric calibration for infrared systems with high dynamic range can be achieved only with a low-temperature blackbody in the outfield. The proposed method, with the advantages of simple operation and strong real-time, has a value for application.

Planar waveguides were fabricated in fused silica and quartz crystal by Cu2+ ion implantation respectively. The guiding mode property was investigated in two types of waveguides by the prism-coupling method. The results indicate that an enhance-type waveguide formed in fused silica, while a barrier-type waveguide formed in quartz crystal by the same ion implantation. The anealing effects to the effective refractive indices of guiding modes in two types of waveguides were researched. The effective refractive indices of the guiding modes in fused silica decrease with the increase of annealing temperature. However, in quartz crystal the effective refractive indices of the guiding modes increase firstly and then decrease with the increase of annealing temperature. In order to investigate the formation mechanism of two kinds of waveguide, the distribution of the electronic and nuclear energy deposition in fused silica and quartz crystal were simulated using the SRIM code. In addition, the refractive index profiles of the types of waveguide were reconstructed. The simulation results show that in fused silica the main reason of the waveguide formation is that the refractive index in the near-surface region is larger than the substrate. However, in quartz crystal waveguide the major formation reason is that the refractive index at the end of ion track is less than the substrate region. Therefore, the electronic energy damage plays an important role for the formation of fused silica waveguide, while nuclear energy deposition is the dominant factor in the quartz crystal waveguide.

Based on the theory of Surface Plasmon Polaritons(SPPs) and the Metal-Insulator-Metal(MIM) waveguide structure, a waveguide structure was proposed, which consists of a square split-ring resonance cavity, a baffle and a MIM waveguide. The transmission characteristics of this structure is calculated by using the Finite-Element Method(FEM).The simulation results show a Fano resonance in the transmission spectra, and the resonant wavelength can be easily tuned by changing the length of the square split-ring resonance cavity or the width of the split. The sensitivity and the figure of merit of this structure is 1 600 nm/RIU and 1.3×105 separately. By changing the position of the split, double Fano resonances can be observed in the waveguide with a sensitivity of 1 700 nm/RIU and the figure of merit of 8.3×104 respectively. The waveguide structure may have wide applications in highly integrated optical circuits , especially for nano bio-sensor.

The simulation results between different facet reflectivity of external cavity and output power of distributed feedback fiber laser are presented, based on compound cavity laser model and facet reflectivity of external cavity measured by optical spectrum analyzers. And a two elements experiment system is constructed to prove this relationship. It is found that the output power of distributed feedback fiber laser will be increased and the flatness of distributed feedback fiber lasers array will be worsed due to the external optical feedback. And the larger facet reflectivity of external cavity is, the lower flatness of distributed feedback fiber lasers array will be. The influence of external optical feedback to the flatness of distributed feedback fiber lasers array should be considered, and distributed feedback fiber laser which have lower facet reflectivity should be used for constitutes the distributed feedback fiber lasers array.

By using the dispersion pulse propagation theory and the refractive index of air Ciddor equation, the cross-correlation function of the femtosecond pulse laser was derived. According to the theory that the resulting expression of the cross-correlation function depends on the spectral distribution of the laser source, the numerical model of the cross-correlation patterns among pulses of the femtosecond pulse sequence propagating in air with different spectral distribution under different optical path difference and the change of environmental parameters was created. Results show that, the cross-correlation pattern has a stable chirp and linear broadening with the increase of propagation distance, but the change of the environmental parameters give rise to the shift of the correlations patterns without any extra linear broadening or chirp.

The Non-periodic Optical Superlattice (NOS) structure was designed by using the the Nonlinear Conjugate-Gradient(NCG) algorithm, and the applicability in the NOS structure of the relative tolerance function mentioned in Ref.[12] was studied. The results show that, this relative tolerance function can apply to the NOS structure well, and the NOS structure is more general to compare with the Aperiodic Optical Super-lattice(AOS) which is used in Ref. [12]. When u′2(xn) and n keep a good linear relationship, the relative tolerance function curve calculated in the NOS structure is nearly coincident with that mentioned in Ref.[12], which shows that a Quasi-Phase-Matching(QPM) is well satisfied in the NOS structure. The applicability in the NOS structure of the relative tolerance function which is under the case of phase mismatching was also furtherly investigated by introducing the random error in the sample. The results show that, the relative tolerance function curve calculated in the NOS structure is not coincident with the standard curve under the case of phase mismatching, and as the mismatching degree increases, the relative tolerance function curves exhibit a larger deviation from the standard one. The applicable scope of Un-depleted Pump Approximation (UPA) can be approximately calculated by using the relative tolerance function when this deviation is not large.

The quantum effects on the negative refraction index of the mesoscopic left-handed transmission lines were investigated by the thermal field dynamics theory in microwave frequency band. The results indicate that the negative refraction index increases with the fluctuation of current and the decreases with the temperature and frequency emerge. And the negative refraction index rangeability is manipulated by the photon numbers. The conclusions can provide reference for the miniaturization and integration application of left-handed transmission.

Compared with the traditional finite-difference time-domain method, the symplectic finite-difference time-domain method has high precision and low dispersion. The traditional finite-difference time-domain method arises low accuracy and great dispersion error. Also it has destroyed the symplectic structure of the Maxwell’s equations and causes the poor stability. But, the symplectic finite-difference time-domain method can overcome these shortcomings and ensure the accuracy and stability of the whole simulation. So, this paper researches the band-gap characteristics and the transmission coefficient of the plasma photonic crystals with the symplectic finite-difference time-domain method and traditional finite-difference time-domain method. The results have proved the advantages and feasibility of the symplectic finite-difference time-domain method.

The basic imaging formula of the fly-eyes illumination system has been deduced from the optical imaging point, according to the characteristics of LED emission and the characteristics of the Color-Filter Liquid Crystal on the Silicon(CF-LCoS). The initial lighting system of the CF-LCoS can be given with the basic formula of the fly-eyes imaging system by considering the size of the target area of the CF-LCoS , the incident angle of the light beam on the CF-LCoS , the requirement of the spot size and the divergence angle after LED′s light shaping. Then with the multi-conjugate imaging relationship of the fly-eyes illumination system, the fly-eyes imaging and the relay lens imaging can be optimized, which can be linked up to form a fly-eyes and the illumination system of the CF-LCoS under large illumination angle through the matching principle of the aperture and the intermediate image finally. The problem of lighting system efficiency, uniformity and large incident angle can be solved by using less number of eyes under the condition of ensuring the illumination requirements of the CF-LCoS. This method is simpler and more accurate than the traditional calculation method. The simulation results of the non-imaging software show that the illumination is with good uniformity and high efficiency. Finally, the experimental prototype is designed and fabricated to verify the correctness and effectiveness of the proposed method.

The progressive addition lenses have been used widely applied, because its advantages can meet the requirements of distant and near vision at both time. The basic structure, design and evaluation method of progressive addition lenses are introduced in this paper. The relationship between surface error and optical power of progressive addition lenses is analyzed. The relationship equations are derived from the surface equation and sphere equation. Based on the national glasses fabrication standard that the difference between practical optical power and nominal designed value should be less than 0.1D during the lens effective area, A progressive addition lenses example with 2.0D addition (6.0D~8.0D) was designed, evaluated and surface error tolerance analyzed. After fabrication with given surface error, the optical power difference is calculated correspondingly. It is shown that the simulation result is consistent with the solution of relationship equations. The relationship model provides theoretical basis for the surface precision during lens fabrication process.

According to the working principle of Czerny-Turner structure spectrometer, to make the system miniature and portable as specific design objectives, a crossed-asymmetric Czerny-Turner spectrometer with spectral range of 200 nm~900 nm was designed. Based on the spectrometer resolution and spectral range, we could determine the general structure. Then the primary aberration was used to optimize the initial structure, first proposed combining the spherical aberration constraints and aperture surface selection and designed process to determine the collimating mirror aperture, initial grating size and focusing lens aperture of the center wavelength, and then combined with the constraints of coma to calculate the spherical mirror off-axis angle, and based on geometric optics to determine the initial focus lens aperture. The imaging simulation, analysis and optimization for optical system were carried out with optical design program ZEMAX. The spectrum of mercury-argon light and the spectrum of halogen light are measured by our self-developed spectrometer. The results of analysis demonstrated that the optical system achieved central wavelength resolution less than 1 nm, edge wavelength resolution less than 1.5 nm, in conditions of the slit width is 25 μm, the groove spacing is 1.667 μm/line.

The imaging and dispersion characteristics of membrane diffraction primary lens were studied, and the strong dispersion of diffraction primary lens was corrected by using the reflective achromatic optical light path with diffractive optical surface. Thus, the membrane diffractive optical system with an aperture of 10 m and a total length of 115.73 m was designed with the waveband of 40 nm, the field of view of 0.02°. The results show that, the focal length difference between the two edge wavelength of 0.58 μm and 0.62 μm decreases from 5.34 m to 17.27 μm by uing the achromatic optical path. This study presents a design method for the imaging system with membrane diffraction primary lens, which can provide references for the engineering research of the large aperture membrane diffraction imaging system.

Lobster-eye is an optical focusing system that simulates the lobster vision, and is very suitable for appling in the X-ray pulsar imaging detection on the satellite platforms. Based on the principle of grazing incidence, theoretically quantitive relationship between photon energy and full reflection critical angle and reflectivity for different metallic film are studied. A method for calculating the effective detection area of the Angel lobster-eye optical system is proposed, and formulas are duduced. Montel-Carlo experiment results is agree with the theoretical figure. In the range of 1~10 keV, the effective detection area of the lobster-eye optical system is approximately negative exponential function of photon energy, specific parameters depending on film roughness.

A tunable optical oscillator based on a planar optical waveguide resonator was proposed. In this oscllator, the phase modulator is connected in series with the optical waveguide resonant cavity to replace the intensity modulator, the long fiber and the filter in the traditional system. Because the optical resonator is particularly sensitive to photon frequency and photon phase, by adjusting the laser wavelength, not only the intensity of the light can be adjusted, but also the frequency of the microwave photons can be selected. When the photon is resonant in the waveguide cavity, it will produce a strong delay characteristic, which can be used to replace the long fiber in the traditional system. The whole photoelectric oscillator system volume is long 29.5 cm, wide 21 cm, high 7 cm. In the experiment, each time to change the photon wavelength 0.1 pm, resulting in a 12.5~35.5 MHz step tuning effect, tuning range of 2 GHz. The system generates a 10 GHz microwave signal having a phase noise of －109.7 dBc/Hz@10 kHz at a center frequency of 10 GHz. Which provides a new idea for the miniaturization and practical application of the optical oscillator.

The characteristics of two types of Optoelectronic Oscillators (OEOs) based on phase-locked loop technique and injection-locked technique were analyzed and compared. The noise transfer functions of the two types of OEOs were deduced and verified by experiments. The similarities and the respective merits between the two techniques were discussed. There is a problem of losing lock in the two types of OEOs because the optical fiber has a high sensitivity to temperature. To solve this problem, a locking state monitoring and feedback system was designed according to the phase difference between the output signal and the reference signal. The system was also verified by experiments.

In order to meet the requirements of optical devices for passing infrared waves and shielding electromagnetic waves, a transparent metal mesh shielding film was fabricated on PET flexible substrates. The influence of mesh parameters on shielding efficiency and transmittance was analyzed, and the structural parameters were selected. For the flexibility and thermal stability of PET substrate, high-quality graphics structure was obtained after optimizing pulling speed, baking time, temperature and other parameters in the lithography process. Transparent shielding film was prepared by magnetron sputtering and the film/substrate bonding was strengthened by optimizing sputtering power, sputtering pressure and other parameters. Finally, a metal mesh transparent shielding film with a line width of 3 μm and a cycle of 250 μm was made. The average transmittance in the 300～2 200 nm band was 77% by spectrophotometer, the electromagnetic shielding efficiency in the 2~18 GHz band which measured by shielding room method is higher than 12 dB.

A structure of one-dimensional bilayer cosine conformal grating crystalline silicon thin film solar cell was designed. The absorption spectra of bilayer cosine conformal grating structure and contrast groups were simulated by using the finite difference time domain method ; The absorption efficiencies of two wavelength regions of 300 ~ 700 nm and 700 ~ 1100 nm were quantitatively analyzed by using the concept of normalized optical absorption density. It was found that bilayer conformal grating structure has better absorption efficiency in full wavelength band and cosine grating has better light trapping and absorbing than rectangular grating in long wavelength region. To analyze the mechanism of optical absorption enhancement, absorption enhancement spectra and distributions of electromagnetic field intensity were plotted. Through the calculation of short-circuit current density, it was found that the short-circuit current density of bilayer cosine conformal grating crystalline silicon thin film solar cell increased by 79.5% relative to planar structure, the short-circuit current density of cosine grating structure increased by 8.5% relative to rectangular grating structure.

This work synthesizes a large class of multifunctional CdTe@Fe3O4/P(NIPAM-co-AA) composite microspheres with superparamagnetic and fluorescent properties by using the polymer template method. The P(NIPAM-co-AA) microspores are obtained by inverse suspension emulsion polymerization. Magnetic nanoparticles were doped into the networks of the polymer template microspheres by a simple swelling method. TEOS and APTES were chosen to achieve amino- functionalization of the magnetic microsphere surface. Furthermore, mercaptoacetic acid modified- CdTe quantum dots reacted with amino functional microsphere, which finally resulted in the mono-dispersed magnetic fluorescent polymeric microspheres. Several techniques, e.g. scanning electron microscope, transmission electron microscopy, fluorescence microscopy and fluorescence spectrophotometer, etc. were used to examine structures and properties of the resulting composites. In summary, the resulting composite microspheres are as large as about 30 μm and exhibit excellent superparamagnetism and high efficient fluorescence quantum yield. The saturation magnetization reaches 5.4 emu/g. This approach to generating multifunctional composite microspheres by combining the magnetism and fluorescence onto micrometer copolymers could not only avoid difficulties in separation of nano-particles, but also lay bases for many potential applications in various fields.