Theoretical analysis and experimental research was done on relation between the light source coherence degree and the maximum diffraction-free distance of the generated Bessel beam. A collimated partially coherent beam generated by a rotating ground glass illuminated by a He-Ne Laser was impinged on an axicon to generate partially coherent Bessel beam. Moving the position of a rotating ground glass to change the coherent degree of the light source, and measure the maximum diffraction-free distance of the generated Bessel beam with different coherence degree, the relation between the light source coherent degree and the maximum diffraction-free distance of the generated Bessel beam were obtained. A Gaussian shell model source was used in theoretical analysis and numerical simulation, the results show that the maximum diffraction-free distance suffers a rapid decline when the coherence degree decreased a little. If the coherence degree of the source decreased from g≈1 to g=0.8, the maximum diffraction-free distance will be only a half of the original, the experimental results is coincident with the theoretical analysis.

In order to study the propagation characteristics of airy beams through negative index medium,the analytical expression was obtained for airy beams passing through the negative index medium based on the ABCD matrix optics theory.The propagation properties of airy beams passing through a negative index medium were obtained by using the formula.Numerical examples show that the intensity and the deflection position of the beam can be modulated by the frequency of the negative index medium.The deflection coefficient of the Airy beams is accelerate deflect as the frequency increases,different deflection position are obtained when the Airy beams propagating along z direction with different frequency.Both the deflection coefficient and the intensity of the Airy beam can be sensitively controlled by the frequency.The results show that it is convenient and efficient to modulate the Airy beam by the frequency of the negative index medium, the results presented in this paper may have some potential applications in optical device design and can be utilized in medicine science.

In considering the exciting ability of driving Distributed-feedback quantum cascade laser in infrared carbon monoxide detection, a novel generator under experimental validation was carried out accordingly. Firstly, low ripple power supply and perfect protective module were developed, which improved the quality of drive pulse significantly and ensured the reliability of the power supply work. Secondly, corresponding function circuits were designed by the concept of “Multiple Isolation”. So the system anti-interference ability was enhanced greatly. Lastly, deep voltage feedback method and proportional-integral-differential control theory were used to improve the stability of drive current efficiently. Utilizing illustrated driver, driving test was conducted on one Distributed-feedback quantum cascade laser with center wavelength at 4.76 μm, which was fabricated by institute of semiconductor, CAS. Experimental results demonstrate during a long-term operation (200 h), stability of drive current is 2.5×10-5, linearity of the drive power system is 0.04%, which meet the requirements of driving Distributed-feedback quantum cascade lasers and provide a strong guarantee for infrared carbon monoxide detection.

A quick and high-precision image center locating algorithm based on the difference between the corresponding ellipse′s long and short axe method was proposed ,to meeting the requirements for high precision and time-saving in real time beam automatic alignment process of the high power laser device. The maximum value of the spot′s area is obtained by acting the Big Law Method, 3×3 Neighborhood Method and Eight-Neighborhood Method on the spot image in turn;Lengths of the long and the short axis are obtained by the analyzing the center distance of the maximum spot, and adjust the spot shape by the deviation of the ellipse′s long and short axe until to the deviation approach to zero;Through analysis the deviation between the actual spot center and the corresponding reference position, the adjusting steps of stepping motor controlled by the closed-loop control method is obtained, and the automatic alignment is realized. This algorithm is verified in the high-power laser device, the experiment results shows that the alignment time of the main amplification of the optical path is shortened to 15 min, the near-field alignment accuracy is better than 0.2%, and the far-field pointing accuracy is better than 1 μrad, all of them meet the alignment requirements of the high-power laser device.

In order to produce the dual-frequency laser with tunable frequency-difference at 1 064 nm, a two-cavity dual-frequency Nd∶YAG laser was designed using a twisted-mode configuration, the two standing-wave cavities of which share the same gain medium Nd∶YAG, and the twisted-mode configuration reduced or even eliminated the spatial hole-burning effect of gain so that the single longitudinal mode can be oscillated in both standing-wave cavities of the Nd∶YAG laser, thus the orthogonally and linearly polarized dual-frequency laser at 1 064 nm was obtained. The principles of both single longitudinal mode selection of the twisted-mode configuration and the simultaneous oscillation of the dual-frequency laser were theoretically analyzed, and the characteristics of dual-frequency laser oscillation and frequency difference tuning were investigated experimentally. The experimental results show that both cavities of the Nd∶YAG laser can steadily oscillate in linearly polarized single longitudinal mode, and the frequency-difference can be tuned up to one longitudinal mode interval by changing the cavity length, the frequency-difference tuning range is 0.3 GHz to 3 GHz.

The radiation force of highly focused hybridly polarized beams on a Rayleigh particle was theoretically studied and the expression was derived.The influence of numerical apertures of an objective and radial coefficient on the radiation force distribution and the longitudinal intensity distribution on the focal plane were numerically simulated.The numerical results show that radiation forces by highly focused hybridly polarized vector beams can be used to trap three-dimensional Rayleigh particles, and the trapping property is affected by the numerical aperture and radial coefficient obviously. Copious experimental data indicate that it can be done only when the radial coefficient is greater than 3.

Two kinds of model, Biological Equivalent model and Circadian Light model which used to evaluate the biological effect of light were discassed and the differences between them were pointed out by fitting curve between the biorhythm factor and human body temperature after several field test. Calculating with the spectrum produced by the LCD screen, it shows that these two models have a stronger restraint of green light band while the red band of light appear not too consistent with the actual results. By tested the forehead temperature under different colors of LED light and fitting with the calculated biorhythm factor, it demonstrates that the forehead temperature increases with the biorhythm factor linearly. And the linear fitting correlation of biological equivalent model is 0.95.

The excitation intensity and excitation duration are the essential experimental conditions of the high-frequency flash method for the measurement of algae photosynthetic parameters. The fraction of reduced primary electron acceptors and the reoxidation extent of these reduced primary electron acceptors were analyzed under different excitation intensities and excitation durations. The analysis results indicate that 30 000 μmol quanta·m-2·s-1 is the optimal excitation intensity and 70 μs is the optimal excitation duration. Under this optimal excitation condition, 96.08% of the primary electron acceptors are reduced and only 9.81% primary electron acceptors reoxidize.

Diffusion model has a disadvantage that exist a large model error in the near light source which lead to a lower accuracy for inversion of optical properties parameters. Therefore, the article proposed a moment-transformation method, which change the form of raw data and improve inverse accuracy. The article compared inverse accuracy of the optical properties under different orders conditions and statistical distribution of fit residuals and analyzed relative error of the reconstruction coefficient under different signal to noise ratio. The results of all set data indicate: 3 order moment-transformation can significantly improve estimation accuracy both optical parameters that 7.04% for μa and 5.55% for μ′s under the no noise condition. three order moment-transformation compared to original and the natural logarithm data transformation, the relatively error decrease 57.59%、8.57% for μa and 42.55%、32.73% for μ′s, respectively. In the case of the certain signal to noise ratio (greater than 50 dB), three order moment-transformation still get high inversion accuracy of optical parameter. Therefore, based on the distance weighted data transformation is an effective means of measuring optical parameters.

Based on principle of edge ray and etendue conservation ideas, the compound parabolic concentrator and freeform lens collimator were designed for high power Light Emitting Diode extended source. By using TracePro software for ray tracing simulation and experimental guidance, a light radiation simulator with uniform illumination output was developed. The divergence angle of simulator output light beam is measured as ±0.2 rad. In the lightscreen of 50 cm distance the beam horizontal uniformity is measured better than 4.1%, and longitudinal uniformity better than 3.8%, within 14 cm×14 cm size illuminated area.

According to the practical solder paste printing inspection of PCB, digital fringe projector design used 0.45 WXGA DMD chip was performed in this paper. The design adopted LED as light source, and combined with lens array for evenness illumination. In order to reduce the influence of nonuniform fringe on inspection results caused by triangular relationship of projection, double telecentric optical configuration was used for imaging DMD-generating fringe on defected surface. The minimal inspection area of projector can reach 1mm2. Simulation results show that illumination evenness of the digital fringe projector on defected surface is about 91%, contrast of projection fringe is better than 0.8, and keep the fringe pitch uniform. Optical projector designed in this paper provides guarantee for inspection application and following fringe analysis.

In order to solve the problems of the existing spectrum detection module in Laser-Induced Breakdown Spectroscopy (LIBS) system, such as low resolution and large size, based on the optical design theory, a small size, and high resolution crossed Czerny-Turner spectrometer was designed. Parameters of the structure and optical elements were calculated. The performance analysis and evaluation of the optical system were carried out by using optical design Zemax software. The results show that the optical system whose effective wavelength range is from 340 nm to 440 nm with resolution better than 0.1 nm, and its size was 200 mm×180 mm×60 mm. In addition, in order to verify performance of the spectrometer, the heavy metal solution was detected with the LIBS system. The experimental results demonstrate that it has various advantages, such as high spectral resolution, small size, low cost, simple structure, and good stability.

The relationship of atmospheric visibility to laser intensity was analyzed based on Mie theory under the conditions of single scattering and multiple scattering scenarios in sand and dust weather. An improved analytical expression of laser intensity and atmospheric visibility was derived in single scattering scenario. The multiple scattering was simulated by Monte Carlo method and compared with single scattering. The results show that the received laser intensity will be increased with the increment of atmospheric visibility and approximate to a saturated value when the laser wavelength and transmission distance is constant. Moreover, when the atmospheric visibility remain unchanged, the received laser intensity will be decreased with the increment of laser wavelength, and with the increase of transmission distance, the influence of multiple scattering will become more and more notable.

Based on angular spectrum diffraction theorem and circular Gaussian distribution model of scattering media, light focusing through scattering media was numerically simulated. A high contrast focus in the target area is produced by using a feedback optimization algorithm to shape the wavefront of the scattering light. By adjusting the target area, it is also possible to form one or multiple foci at will. The influence of the number of square segments of the spatial light modulation and the phase precision of a single segment on the intensity enhancement was discussed. The result shows that the light intensity at the target area increases linearly with the increasing number of square segments of the spatial light modulation, and becomes stronger with the increasing phase precision.

Based on Rytov approximation and extended Huygens-Fresnel principle, the analytical expressions for average intensity and scintillation index on target plane in non-Kolmogorov weak turbulence along slant paths were derived, the system efficiency of heterodyne lidar wass given. The system efficiency of heterodyne lidar is examined and the effects of exponent parameter, zenith angle, structure constant, system configurations and telescope aperture on system efficiency are also analyzed.It is shown that when the generalized index is less than 3.2 or greater than 3.8, the system efficiency decreases fast as the index increases. System efficiency decreases with the increase of zenith angle. System efficiency of bistatic configurations is smaller than that of monostatic configurations. With the increase of the telescope aperture, the system efficiency arrives the minimum, and eventually flattens out. In near field, the system efficiency of collimated beam is larger than the other two forms, but in far field the system efficiency of divergent beam is the largestone.

The imaging characteristics of CCD were analyzed,a geometric calibration experiment on side-scatter lidar was designed,the each CCD pixel angle was achieved,and the relation between CCD pixels and the position of scattered light was established.Two experimental signals were calibrated using this method.The calibrated results are compared with POM02 in aerosol phase function,and with the backscattering lidar in signal,respectively.The comparison results indicate that the profiles of aerosol phase function from this method and from POM02 are same,and the signal from side-scatter lidar has the same tendency with the range-corrected signal from backscatter lidar above 650 m.Moreover,side-scatter lidar overcomes the shortcoming that the backscatter lidar can not detect the full signals in near range.This calibration method is reliable and useful for further studying the spatial-temporal aerosol profile in near surface by side-scatter lidar.

Pseudo millimeter wave ultra wide band signals have the characteristics of narrow pulse width, low signal strength , which make it is not easy to detect. To deal with such problem, two optics assisted envelope detection schemes were proposed. Firstly, a fiber Bragg grating was used for filtering one of the first sidebands at the output of the modulator, then the envelope of PMM-UWB signals for decision were obtained after photo-detection and low pass filter. Based on the method of mathematical derivation and numerical simulation, the effects of phase modulator or intensity modulator on the output envelope signal amplitude were analysed respectively. The results show that intensity modulator requires bias control to maintain a stable optical operating point, when the bias point of intensity modulator was switched to minimum transmission point, the maximum amplitude of envelope signals were acquired;phase modulator do not include the bias control, the amplitude of envelope in phase modulator is equal to the maximum amplitude in intensity modulator approximately. Compared with intensity modulation scheme, the phase modulation scheme has more advantages, such as simple structure, low insertion loss.

A novel method for measuring electrodeposition stress was presented.Its mechanism is that the center wavelength of metal coated Fiber Bragg Grating sensor shifts under the action of the electrodeposition stress when the FBG is used as cathode in electrodeposition;based on the shift,the stress can be calculated.In the measurement,the center wavelength shifts of the FBG during deposition are recorded by FBG interrogator and these records are divided into many time segments with equal interval.Based on average depositing velocity and the relationship of FBG′s stress sensitivities with deposition thickness, the stresses producing in every time segment are calculated individually.Stress evolution is obtained by adding up these segmental stresses.The process is stress evolution during electroplating nickel was tested by using electroless Ni-P coated FBG sensor.The result shown that the FBG′s sensitivity is higher than 7pm/MPa under the condition that the nickle thickness is less than 50μm,and the degree of accuracy is more than 0.14 MPa.After deposition for 6 000 s,the accumulative pressure stress is 173.049 9 MPa.

A kind of single-core PCF splitter based on tellurite glass was proposed, defected holes were arranged in the outer cladding, they can bring about strong coupling effect between defected mode and the fundamental mode. FEM was used to analysis its characteristics. The simulation results show that this kind of splitter can split light in the bands of 1.3 and 1.55μm, propagate along the orthogonal polarized directions. For a propagation distance of 15 mm, the -20 dB bandwidth of crosstalk in 1.3 and 1.55 μm bands, reach 44.2 and 67.1 nm. The confinement loss at the wavelength are 0.063 dB and 0.0 48dB. The proposed splitter has low crosstalk and low confinement loss.

The detection and alignment of polarization axis is a key technology in PMF’s application.In order to improve the accuracy of the end face detection of polarization axis,a sub-pixel edge extraction method based on surface fitting was proposed to improve the accuracy and the normal distribution of the detection result was used to improve the precision.Based on the normal distribution of the detection result,a aligning method based on normal distribution was put forward.An automatic aligning system was established.The experiment shows the sub-pixel edge extraction method can decrease the error by 45% and the ellipse fitting can reduce the error by 15%.The alignment experiment figures out that the bias of aligning method based on probability is less than 0.1°.

A method for choosing angle of reference beam in computer-generated holograms based on spatial frequency analysis of principle fringe pattern was proposed. The rules for reconstructed image rightly were obtained through analyzing the spatial frequency of principle fringe pattern. The angles of reference beam in the holography reconstructed system based on spatial light modulator were computed. The holograms of one image plane with size of 22.5 mm×26.1 mm were generated at the distance of 1 000 mm when different angles of reference beam were chosen. The digital and optical reconstructed experiments were conducted respectively. The results indicate that the angle of reference beam must be chosen in the range which is from 0.893 8° to 1.398 0° in order to achieve good quality of reconstructed images. If the angle of reference beam is smaller than 0.893 8°, the reconstructed image and the conjugate image could not be separated completely, whereas the reconstructed image would overlap with the conjugate image of the next order if the angle of reference beam is larger than 1.398 0°. The experimental results validate the theoretical analysis very well.

In a holographic waveguide display system, the diffraction efficiency, location, and length of each ouput grating make great impact on the uniformity of output intensity and ratio of energy utilization. Generally uniformity of output intensity is decided by the diffraction efficiency distribution of each output grating, and ratio of energy utilization rests with the location and length of each ouput grating. Firstly, aming at the uniformity of central field of view, the diffraction efficiency distribution of corresponding output grating was optimized and curve fitting, and a continuous and increasing curve of efficiency distribution was obtained. Similar processing was carried out for other gratings corresponding to other FOV. Calculation results demonstrate that the uniformity of output intensity of HWDS will be improved notablely when output gratings with optimized continuous and increasing diffraction efficiency distributions are used than that of traditional output gratings with step diffraction efficiency distributions. A shifting-optimization method was proposed to optimize the location of each grating according to the size of exit pupil and usage distance, so that the ratio of energy utilization of HWDS could be greatly incereased resulted from the reduction of the invalid diffraction region.

The exposure sensitivity and polarization sensitivity of spiropyran doped polymers after the irradiation in short-wavelength range were significantly improved. Based on such properties, holographic grating recordings accompanying with a linearly polarized blue-violet beam (405 nm) in the photochromic film were performed by two coherent green beams (532 nm) for s-p formation. Under the bi-photonic action of 405 nm and 532 nm, temporal evolution of diffraction efficiency was strongly dependent on auxiliary light intensity. It was found the blue-violet irradiation plays double roles in holographic recordings: on one hand, providing the molecular orientationable merocyanine for the recording beams;on the other, disrupting the formation of refractive index gratings and reducing the conversion activity of merocyanine molecule.Taking the existence of merocyanine aggregation in the random light field of interference fringes into account, an theoretical model was established which reveals the relationship between diffraction efficiency and light-rate-constant of each molecular.The experimental results are precisely fitted with this model, the microscopic reaction mechanism of spiropyran and merocyanine molecules in polarization holographic recording was effectively explained.

In order to solve the problem that phase can’t be quickly and accurately unwarped in wavelet transform profilometry, a algorithm was presented which could effectively suppress noise. Firstly, the characteristics between the amplitude of wavelet ridge coefficient quality map and phase derivative variance quality map were analysized. Then, based on the deviation degree between phase vaule and its mathematical expectation, a “the amplitude of wavelet ridge coefficient variance derivative” quality map was constructed with the wavelet ridge amplitude coefficient variance matrix and variance derivative. Finally, from computer simulation and real experimental modeling, unwrapping phase based on the new quality map was compared with the traditional phase unwrapping method and the improved quality map method. Experimental results show that the accuracy of phase unwrapping is improved, the phase unwrapping error is decreased by 2.61 percent. The proposed quality map is construted quickly, phase unwrapping guided by the new quality map can obtain accurate absolute phase and effectively suppress noise, which can reconstruct accurate 3D model through the obtained absolute phase.

Because traditional background suppression methods don't take full advantage of direction information, small target and edges can't be distinguished effectively and some background may expose. A new method based on improved shearlet transform and image guide filter was proposed. Firstly, nonsubsampled wavelet transform and shear directional filter bank is adopted to decompose the infrared image into multi-scale and multi-direction to obtain high frequency and low frequency coefficients. Then the image guide filter is used to adjust the high frequency coefficients of each sub-bands to suppress the dim and small target signal and predict the background. Then the estimated background is obtained by the inverse transformation. At last, the suppression result is obtained by subtracting the estimated bcakground from the original image. Several group of experimental results demonstrate that the presented method can suppress the background and enhance the small target signal effectively, compared with several classical methods, such as Max-Median、TDLMS and Top-hat. The proposed method can effectively improve the detection probability of infrared search and tracking system for infrared dim and small target.

In order to recognize targets in images fast and truly, an automatic target recognition method was proposed based on image entropy and speed up robust feature. First, image entropy was computed in different blocks, and regions full of texture were filtered out by threshold. The local key points in regions of interest were extracted by incorporating the Hessian and Harris detectors. Then, feature descriptors were established and principle component analysis was employed to reduce the dimensionality. Finally, nearest neighbor distance ratio classifier was explored in double directions and wrong matches were eliminated by random sample consensus. The experiment results demonstrate that the recognition rates for images in simulation database with varied view-points, scales and illuminations are 87.12%, 75.31% and 84.98%, and the computing time is 70.35 ms, 71.27 ms and 220.63 ms, respectively. Moreover, the correct matching rate for an aerial large planar array image of 8 956×6 708 pixels is 78.13% and the computing time is 68.09 s. Compared with speed up robust feature, the proposed method performs better both in recognition rates and computing time.

Confronted with the requirement of the high resolution earth-observation system of high-speed aircraft working in near-space environment,and the imaging system with dynamic optical windows is likely to suffer from extreme dynamic aberration,complex imaging quality compensators and bad real-time character,the traditional imaging quality compensation was improved and the adaptive optical (AO) technique was explored as a novel way of solving the problems.The image sharping function optimization closed-loop adaptive wavefront correction algorithm was used.Simulations results indicate that the correction method can make the PV (peak to valley) waves of the Zernike aberration term in reduce to about 17.5% and the RMS spot radius to about 10.61% less than before correction the system which has 60°FOR (field of regard).By correction with this method,the residual aberration is much less than the baseline system and the imaging performance can be almost diffraction limited.

In order to solve the problem of image distortion of the three-dimensional reconstruction underwater, a model based on the non-parallel binocular stereo vision system was proposed, which could transfer the image shooted through a plat waterproof cover underwater into the image shoted in air, and general conditions were presented to use it. When the focus of lens is on the surface of the water, there is a one-to-one correspondence between the underwater image and the image-without-water. If the focus of lens is outside the water, the proposed model still valid when the distance from the focus to the object is far greater than the focal length and the distance from the focus of lens to refractive surface along z axis. Three-dimensional reconstruction of the feature points was used in experiments to verify the validity of the model. The results show that with the mentioned method, the average coordinate errors of the feature points are 2.23%(x), 1.51%(y), 1.10%(z), respectively, compared with the actual one. The proposed model provides a basis of applying the three-dimensional image reconstruction.

Chrysanthemum-like Zinc Oxide (ZnO) nanorods was fabricated and characterized by hydrothermal route, the diamond was mixed to prepare electrophoretic fluid. After electrophoretic fluid was dispersed by ultrasonic cleaning machine, the coatings were deposited on titanium substrates. Field emission characteristics were tested after heat treatment. Results show that turn-on field of undoped diamond cathode is 7.3 V/μm and field emission current density is 81 μA/cm2 when electric field is set at 20 V/μm, while the doped samples show low turn-on field of 4.7~6.0 V/μm and high field emission current density of 140~158 μA/cm2. The reason is that after the interfusion of nano-ZnO, the electron transport capacity of coating is enhanced, the number of effective emitters increase and field enhancement factor β is improved. Because of diamond, the good bonding between coating and substrate is guaranteed after heat treatment and ohmic contact is formed, which reduces the thermal effect of field emission current. The stability of field emission current declines with the increasing amount of mixed ZnO. Both field emission current density and its stability should be considered, so mixing an appropriate amount of ZnO with nano-diamond can effectively improve field emission characteristics.

In order to obtain high quality far-infrared chalcogenide glasses, traditional melt-quenching method jointing with dynamic glass water removing under high temperature and raw material solidifying under vacuum evacuating process have been adopt to prepare Te chalcogenide glasses with high halogen content (halogen Imax= 40 at.%), and analyzing a series of Ge20Te80-xIx (x=10,15,20,25,30,35,40) chalcogenide glass samples. Vis-NIR absorption spectra and infrared optical transmission spectra will be acquired through using spectrophotometer and Fourier transform infrared spectroscopy instruments. Internal microstructure of the glasses is analyzed by using Raman spectroscopy and X-ray diffraction instruments. The research shows that with the increase of the halogen elements I, blue shift will occur in the visible / near-infrared absorption spectrum of short-cut edge, the optical band gap will increase gradually, and the glasses remain pervious to light from 1 μm near-infrared to 25 μm far-infrared wavelength. In addition, it is found that Ge20Te65I15 glass sample has the largest glass transition temperature near 138℃ centigrade, and the infrared transmission rate is also the highest among these glasses, up to nearly 50%.

A slow light photonic crystal coupled-cavity waveguide by introducing two additional holes into the single line-defect structure was proposed. The characteristics of slow light in the coupled-cavity waveguide were investigated with Plane Wave Expansion (PWE) method. Influences of the boundary rows shift and the coupled-cavity length on the dispersion and the group velocity of device were studied. Compared with the boundary rows shift method, the group velocity is reduced to 0.03c (c is the light velocity in vacuum) by modifying the coupled-cavity, meanwhile the effective wavelength range is close to 20nm. Finally, the transmission field distribution under different incident wavelength was analysed with Finite Difference Time Domain (FDTD) method. A good transmission character of the proposed structure is verified by researching transmission field distribution under different incident wavelength in photonic crystal coupled cavity waveguides.

Aimed at the problem of dynamic false contour in LED display when playing the motion images, a novel of PWM method named concentrated gated pulse width modulation was proposed. Based on the GPWM, the approach fixes the decimal subfields on the center of one PWM period, and then figures out the number of subfields corresponding to the integer weight bits, and locate them near the decimal subfields. Theoretical analysis and experiments show that CGPWM has the similar lighting function with linear PWM, and consequently reduces the average DFC values between any two gray levels from 0.6 under the control of GPWM to 0.2. CGPWM can eliminate DFC effectively while maintaining high refresh frequency and rich gray levels, and thus improve the image quality greatly. Furthermore, the processing to implement CGPWM is simple without extra hardware.

The influence of imperfect Faraday mirror on secret key rate of continuous variable quantum key distribution system in reverse reconciliation is considered with theoretical analysis and numerical simulation. It takes entanglement based scheme. It′s found that Faraday mirror′s imperfection reduces the secret key rate and transmission distance of system. The impact increases if the imperfection turns more serious. Besides it finds using great modulation variance can reduce the impact of Faraday mirror significantly.

The quantum properties of weak cohetent state in terms of squeezing effect and antibunching effect were investigated in the diffusion. Master equation of density operator in the diffusion process can be concisely solved by virtue of thermo-entangled state representation and the technique of integration within an ordered product of operators, which contains normal ordering, antinormal ordering and Weyl ordering. The solution of master equation of density operator in diffusion process was given by Kraus operator. The evolution formula of the field density operator which is in weak coherent state initially was get . Its squeezing effect and antibunching are investigated by the numerical method. The effect of decoherence on its nonclassical property is discussed. Numerical results show that compression depth is weakened and the compression range decreases with diffusion time increasing. On the other hand, the light field displays antibunching effect in the early diffusion. When the diffusion time is greater than a certain value, its antibunching effect disappears.

For the sake of optimizing its measure range,sensetivity and linearity, a tapered Surface Plasmon Resonance (SPR) fiber probe was applied as the substitution of the uniform fiber probe because of its abundant lossy modes.Simulation results and experimental data shew that this tapered probe had a SPR asorption spectrum with better symmetry and its resonance wavelength could change responsing to a bigger range of measured refractive index with a stable wavelength resolution. After constructing a closed-loop SPR fiber sensors based on the tapered probe according to frequency modulation principle, the deionized water sucrose and ethanol solution, whose refractive index value ranged from 1.33 RI unit (RIU)to 1.43 RIU with different concentration, were elected as measurand.The measured results were analyzed and verfied using an Abel refractive index meter.The experimental results demonstrated that the closed-loop SPR fiber-optic sensors with a tapered SPR probe had the sensitivity of 0.00003 RIU, wavelength resolution of 4500 nm/RIU and with better performance in terms of dynamic range, sensetivity and linearity, than that with a uniform SPR probes.

The Doppler frequency time-variation exist in the received echo when imaging maneuvering targets by Inverse Synthetic Aperture Laser radar (ISAL). Based on a keystone transform in the azimuth time-frequency domain, a fast azimuth imaging algorithm of ISAL for maneuvering targets is proposed. Since the ratio of the chirp rate to the initial frequency is constant for all multicomponent linear frequency modulation subechoes in each range cell, all these multicomponent linear frequency modulation subechoes can be simultaneously transformed into multi-component single frequency subechoes by using the keystone transform in the azimuth time-frequency domain, and hence fast Fourier transform can be used for azimuth focusing. In addition, a precise and efficient method based on the fractional Fourier transform and the minimum entropy is proposed to estimate the ratio of the chirp rate to the initial frequency. Simulation results prove that, comparing with the range-instantaneous Doppler algorithm based on the Radon-Wigner transform, the proposed algorithm is more efficient and can preserve more information details of the target.

To effectively monitor methane concentration in the underground, for interference large characteristics underground , combined with real-time monitoring for methane concentration requirements, self-eliminate vibration optical structure was designed with rectangular prism linked, and the real-time data communication system was constructed based on the wireless network. In interferometer system, the position of two rectangular prism were fixed. The two beam splitters with connecting rod so that it can rotate synchronously, and the optical path difference is generated by rotation. As a result of the link structure, the vibration introduced into the two beam splitters are present in equal amounts at any time. Because the results was calculated used the difference value, therefore, it can be completely destructive effect. By analyzing the maximum range of rotation of beam splitter, the optical path difference range of the system can be calculated. Then through Beer-Lambert law, methane gas concentration detection limit of the system was given in the underground. Experiment in the laboratory and in the main mine roadway were completed, the measured standard concentration of methane gas obtained through a chemical reaction, and the results was compared to test results of WQF530 type spectrum analyzer. The results show that under the conditions of non-interference in the laboratory, the relative error of two detection methods were less than 1.0%;In the underground experiments, the test results of conventional optical detection methods significantly affected by the environment, and relative error was greatly increased, but the test results of the system was stable. So it is strong anti-interference ability and stability.