The force actuator developed for the active mirror uses DC-motor as driving source. Nanometer micro-displacement driving is achieved by means of gearbox,ball-screw-driven stage and groups of springs. Self-locking is performed by leading screw pair. The high gain PID controller based on pull-push force sensor in the feedback path can provide a sufficiently high loop gain to suppress effect of friction on micro-dynamic characteristics so that an excellent linearity is achieved. The actuators were tested in an active mirror prototype with four same actuators and three rigid supports. The measurement of micro-displacement was tested by an optical interferometer. The results of the prototype show that the average displacement resolution is 10 nm,max stroke is ±8 μm,max driving force is ±700 N. The experimental results show that the force actuator is suitable to drive an active mirror. This also provides basis for further optimization of actuator developed for active mirror.

An all-fiber spectroscopic filter of rotational Raman lidar system at a laser wavelength of 532.25 nm for temperature profiling is designed for the first time for filtering the weak rotational Raman signal under condition of intense background noise. The spectroscopic filter is optically constructed with three fiber Bragg gratings (FBG) and three optical circulators,and this configuration can separate two rotational Raman signals at the central wavelength of 530.6 nm and 528.8 nm,respectively,for atmospheric temperature retrieval,and block simultaneously Mie-scattering and Rayleigh-scattering signals with a high rejection rate. The spectroscopic filter parameters are designed and optimized by numerical calculation,and the results show that a rejection rate of larger than 7 orders of magnitude for Mie-and Rayleigh-scattering signals can be achieved,which is needed for rational Raman lidar for temperature profiling.

Preliminary bubble distribution model of ship wake is presented according to the law of bubbles density varying with time and depth,and bubble motion. The laser backscattering properties of air bubbles of the ship wakes under I,IA,IB-type seawater are numerically simulated with the multilayer Monte Carlo method and Mie scattering theory. Different results under 20 m and 30 m depth with the effect of phytoplankton are analyzed. Simulation result shows the light backscattering of ship wakes is increased along the ship stern from far to center;and the backscattering is influenced by phytoplankton in ocean obviously. Results show that the laser backscattering of bubbles of the ship wakes can be used as a fuse of torpedo.

A Rayleigh-Raman-Mie Lidar (RRML) has been developed for measuring atmospheric temperature,density and aerosol profiles. As a combined system,RRML has the ability to measure aerosol and cirrus up to 25 km at night and 5 km during daytime. Especially,lidar is the most efficient method in measuring stratospheric aerosol. Using RRML system,the change of tropospheric temperature,the inversion layer at stratosphere and the background aerosol at stratosphere has been detected in Hefei,China. The results indicate that measurements of RRML are reliable,and RRML can be employed for the routine observations and the analysis of atmospheric temperature and aerosol.

Satellite optical communication system model and its channel MPPM (multi-pulse position modulation),an advanced form based on pulse position modulation,has become a high-performance optical communications satellite modulation. Far-field laser pulse broadening mechanism and effects of clock jitter on the system are studied with the existence of background radiation,atmospheric turbulence and thermal noise of satellite optical communication. Gray-coded MPPM is provided to decrease the clock jitter and inter-symbol interference influence and Gray-code mapping method is designed by constellation diagram. (7,2) MPPM transmission efficiency is more than two times that of 16PPM. Word error probability and bit error probability are analyzed with Gray coded (7,2) MPPM of Poisson-channel. Simulation results show that the use of Gray coded MPPM can effectively resist the timing error and reduce the system bit error probability.

The up conversion method of radio-over-fiber (ROF) system is theoretically investigated and simulated,which is the key technique of ROF system. Based on optical carrier suppression,the 60 GHz optical-wireless signal is generated by the 30 GHz local oscillator in central station (CS). The up conversion procedure also take effect in CS,thus the local oscillator is not needed in the base station (BS). The cost is cut down by this method. Thus the growing need of the high frequency telecommunication can be met. Also,the simulation system is set up to testify the transmission performance of the ROF signal.

The capability of Fresnel zone plate (FZP) for light converging and splitting is calculated for normal incidence plane lights by using the Kirchhoff diffraction formula,and the results show that the capability of light converging and splitting capability is great for normal incident parallel light;the abaxial FZP′s capability of light converging and splitting exceeds the whole FZP for the same area. The ZEMAX analyses show that the abaxial FZP′s light converging and noise restraining ability is greater on condition that its area is bigger when it deviates the same distance from the FZP′s center or the distance it deviates from the FZP′s center is further when it has the same area. An optical antenna is proposed which is composed of FZP and Cassegrain telescope for atmospheric optical communication. It shows that the antenna can converge light and its noise restraining ability exceeds the paraboloid antenna.

According to the characteristic of dielectric constants of the noble metals in the visible and near-infrared region,a first-order perturbation theory is applied to obtain the propagation constants of the TE and TM modes in the symmetrical metal-cladding optical waveguide. In the light of the great propagation loss of symmetrical metal-cladding optical waveguide,a method that sub-millimeter scaled guiding layer is used to depress the propagation loss is proposed. Calculated results of first-order perturbation agree well with the numerical approach.

Dynamic variable delay range is the very important performance for an optical buffer. This paper establishes an analysis model for the optical buffer of double loop configuration based on collinear 3×3 fiber coupler and analyzes the limiting factors which define the double loop optical buffer (DLOB)′s delay range. Numerical simulations find that a large dynamical variable delay range can be realized by cascading DLOB. The experiment demonstrates that a large delay variation of 1-9999 times of basic delay unit,the fine granularity of 25 ns and the BER of the output data is as low as 10-9. The theory model and analytical method obtained in this paper can also be used to analyze other optical switches based on SOA.

The high-speed single-channel transmission of nonreturn-to-zero differential phase-shift keying (NRZ-DPSK) signal is demonstrated using fiber loop. The 414 km fiber loop is divided into four spans,which consist of standard single-mode fiber (SSMF) and dispersion compensation fiber (DCF),and erbium-doped fiber amplifier/distributed Raman amplifier (EDFA/PRA) are used for hybrid amplification. The optical spectrum and eye diagrams of 42.8 Gb/s DPSK signal are obtained after 414 km,828 km and 1242 km transmission. The curves of bit error rate (BER) of the DPSK signal are given both in back-to-back configuration and after transmission using single-ended detection. The BER is 6.3×10-4 after 1242 km transmission,and the error-free transmission can be realized using enhanced forward error correction (FEC).

Mathematical computation for a scheme of balanced optical cross correlation and analysis for the effect of the related parameters on the measuring performance are given. The measuring principle is studied in detail and the mathematical computation is given. We analyze the effect of the pulse width,the crystal length and the group velocity difference between the two perpendicular polarized pulses on dynamic range and sensitivity. On the basis of the theoretical analysis,we construct the experimental platform of the balanced optical cross correlator for the first time to measure the timing jitter of the pulses after transmission through a fiber link of 100 m. The experimental calibration curve agrees with our theoretical computation and the rms of the timing jitter is about 20 fs in the frequency range of 1-100 Hz with the existence of the fiber vibration.

It is asymmetric exposure that generates tilted latent image grating and then influence the shape of the groove during development. In order to simulate the formation of the grating,the asymmetric exposure and development model are introduced,with emphasis on that both the recording sources are on the same side of the substrate. The development of the groove is simulated and the in-situ monitoring curve in the fabrication of holographic grating is calculated. The results indicate that the exposure monitoring curve and development curve of asymmetric exposure are the same with that of symmetrical exposure. The groove will be tilted rectangular or asymmetric trapezoidal when the nonlinear effect is very remarkable or not so remarkable respectively. The asymmetry will be reduced when the nonlinear effect is restrained. A very good agreement between theory and experiment is obtained.

A new image denoising method based on Bayesian estimation is proposed. Normal inverse Guassian (NIG) model is used to describe the distributions of the wavelet coefficients of image,and Bayesian maximum a posteriori probability (MAP) estimator is used to estimate the noisy wavelet coefficients. In order to improve the behavior of Bayesian estimation,wavelet coefficients with different correlation are calculated with different ways. What′s more,Cycle Spinning algorithm is used to modify the Gibbs phenomenon which is caused by wavelet transform without translation invariance. The experimental results prove that this new method can remove Gaussian white noise effectively,reserve the edges better and improve the peak signal-to-noise ratio of the image.

In order to detect the center and radius of concentric circles of photoelectric image of circular hole effectively in printed circuit board (PCB),a novel method for the detection of concentric circles based on Hough transform was proposed. The method for the point sets selection of point Hough transform and the scan direction for image of searching the point sets were improved by using the geometrical characteristic of the concentric circles:The center of the concentric circles was obtained in the accumulative array firstly,radius was obtained by the mean of distance between the circle center and every edge points afterwards,both the circle center and the edge of the concentric circles were detected accordingly. After the contradistinctive experiments for the detection of photoelectric image of PCB positioning circlular hole obtained in reality,the detection method proposed in this paper has obvious advantage in the aspects of increasing detection precision,reducing memory space and time.

A thresholding method for infrared target image is proposed,which is based on the within-class absolute difference,the area difference between background and target,and Niche chaotic mutation particle swarm optimization (NCPSO).The less within-class absolute difference can make the cohesion performance better,and the area difference between background and target is used to inhibit the tendency of an equal division. Therefore,a more reasonable threshold selection rule is formed comprehensively. First,one-dimensional threshold selection method is proposed. The anti-noise performance is improved obviously by extending to the two-dimensional histogram from one-dimensional method. Then the computational burden of finding optimal threshold vector is large for the two-dimensional thresholding,thus NCPSO is used to find the optimal threshold vector. Finally,the proposed method is compared with Fisher method,the Otsu method and the maximum entropy method. The experimental results show that the proposed method is effective for less target infrared image thresholding and the running time is significantly reduced.

The combination of optical microscan and sub-pixel imaging technology is an effective method to improve the spatial resolution of infrared (IR) detectors. According to analyzing the optical microscan principle and the interpolation reconstruction model,a high resolution imaging algorithm is presented which is based on Lagrange polynomial. Firstly,the proposed algorithm divides the image into different isotropic areas besed on local gradient,and secondly adjusts Lagrange exponents adaptively in these areas. Experimental results show that the proposed algorithm can eliminate image blurring arised from optical microscan effectively,improve spatial resolution of IR imaging system and has good application value.

An object detection method based on statistical theory and generalized likelihood ratio tests (GLRT) method is proposed to solve the object detection problem under photon noise limited condition. The object under photon noise limited condition follows Poisson distribution and present particle states. And the signal-to-noise ratio (SNR) of the image is low,so it is hard to detect and identify. Statistical decision formula has been obtained by Poisson distribution probability function and GLRT method under the known grey level image of object. Object detection is determined after the calculation of GLRT value. Simulations and experiments show that the method has good object detection performance,and the results also verify the effectiveness and practicability of the method.

Phase unwrapping is a very difficult problem because of the existence of many unpredictable factors. In order to acquire the more accuracy phase unwrapping,a detailed analysis about the several classic quality weighting factors is given. First,the full mathematical formula of them are provided,then the principle of derivation is described and the characteristics of them are analyzed. According to their physical meaning,some improved algorithms in the same field or related fields are proposed. The experiments prove the feasibility and superiority of improved algorithms. It is also testified that the analysis has universal guiding significance for understanding and studying phase unwrapping.

More and more aerial imaging devices appear with the development of aviation technology,and imaging devices demand more and more high focusing precision. This paper discusses an autofocus method of aerial imaging device,in which,principle of autofocus control and grating method are analyzed in detail,flow chart of autofocus system in whole aerial imaging device is given out and off-focus quantity allowed is computed and verified in experiments,and indicates how to proceed with automatic focusing compensation at the actual photographic process. The experimental results show that using the method of automatic focusing,focusing precision is less than 0.02 mm,focusing time around 5 s.

A concept of incoherently synthetic aperture imaging ladar (SAIL) and its architecture and algorithm is proposed on the basis of computerized tomography (CT) and the detailed analysis and mathematics are given. The feature is that the difficulties in the signal collection and data processing are importantly relaxed. The proposed SAIL has three operations of conventional,inverse and CT spotlight modes,includes two sensing techniques of range resolution and Doppler resolution,and provides a variety of dimensional transformations for imaging that not only for 2-D range or Doppler resolution imaging of 2-D targets but also for 3-D range resolution as well as in the depth compressed 2-D range-resolution and 2-D Doppler-resolution imaging of 3-D targets. Due to the simplification in configuration and diversity of operations,it has a great potential for applications in the extensive fields.

The three strange phenomena in measuring the refractive index of transparent medium with Michelson interferometer were analyzed. By considering the light dispersion and simplifying the visual function,the visibility of interference fringe,the range for moving mirror and the expression of refractive index were obtained. Meanwhile,the results were examined by experiments. Experimental results show that the refractive index measured with the above method is not the traditional phase refractive index but is the group index. Further more,the spectral dispersion at the central wavelength can be obtained by the measured group index and the known phase index.

A rapid and precise algorithm without phase unwrapping for phase retrieval from a single carrier-frequency fringe pattern is proposed. The algorithm first gains sinusoidal component and cosine component of the fringe pattern by Hilbert transform twice,and then phase is retrieved by the line integral of its gradient calculated by the sinusoidal and cosine components. The performance of the proposed method is evaluated by computer simulation and experiment. The phase error from phase unwrapped by Fourier transform is avoided. The algorithm is simple and insensitive to the shadow and discontinuous region.

The cyclic radial shearing interferometry, which can be used to obtain the information of tested wavefront by only one interferogram, is suitable for dynamic wavefront measurements. Simultaneous phase-shifting technique which is convenient for interferogram processing, is adopted. Based on the cyclic radial shearing interferometry, one original interferogram is divided into four interferograms which have π/2 phase-shifting interval simultaneously by using a 2-dimentional orthogonal grating and polarization phase-shifting method. And the wavefront of the test piece is recovered with the 4-bucket algorithm and iteration method. The feasibility of the cyclic radial shearing interferometry based on polarization phase-shifting is validated by theoretical formula derivation, simulation analysis and primary experimental testing, the result shows that RMS precision is better than λ/100. Furthermore, the means with diffraction grating splitter and polarization phase-shifting, which is anti-vibration, not only can be used to overcome the disadvantage of complicated single interferogram processing, but also can be propitious to improve the ability of anti-disturbance of radial shearing interferometry.

Physical mechanism of the sideband asymmetry is theoretically analyzed in the fiber ring lasers,A passive mode-locked erbium-doped fiber ring laser is constructed in the experiment,The obvious asymmetry of the spectral sidebands in an L-band is obtained by adjusting polarization controllers. The asymmetry of sidebands can be observed in two aspects:on the one hand,the asymmetry of the power between the positive and the negative order numbers is obvious,which can be observed that the intensity of the positive second order is higher 14.28 dBm than that of the negative same order;on the other hand,the sideband asymmetry numbers from the positive to the negative orders are also obvious,the number of the positive orders is more 5 numbers than that of the negative. The sideband asymmetry is useful for the research of eliminating the sidebands and acquiring the ideal soliton pulses and so on.

An electro-optic (EO) Q-switched Nd:YVO4 laser with high repetition rate of 30 kHz,end-pumped by a continuous-wave (CW) laser diode (LD) is reported. Using La3Ga5SiO14(LGS) single crystal as an EO Q-switch and designing an efficient and stable resonator,the repetition rate of EO Q-switched operation can be changed from 1 Hz to 30 kHz. Using an output coupler with transmittance of 50%,an output pulse train with pulse energy of 0.4 mJ and pulse width of 6.3 ns is obtained at the repetition rate of 5 kHz. An average output power of 6.2 W with the pulse width of 9.1 ns is obtained when the repetition rate reaches 30 kHz,the slope efficiency and dynamic to static ratio are 32.7% and 83%,respectively. The beam transfer factor M2 is measured to be less than 2. Experimental results show that the output level has great potential for further development.

Chromatic aberration associated with large-aperture lens in high-energy petawatt laser system affects the focused intensity. Diffractive optical element has been used to pre-correct primary axial chromatic aberration. Temporal distortion and spatial convergence of focal spot can be improved. A single diffractive chromatic corrector is designed with zero power facilitating alignment and minimal groove of several micrometers. It will serve as a new proposal for correction of chromatic aberration on high energy petawatt laser system.

A method of recognition of the palmprint texture,with rich information,strong stability,and low resolution collection is proposed. This method first calculates the phase congruence of every point in the palmprint image from 6 directions and sets the direction corresponding to the maximum of phase congruence of every point as the direction of log-Gabor filter,and then at that direction extracts phase information of every point of the image with log-Gabor filter,and further quantifies and codes real and imaginary parts of the phase information. Thus the palmprint phase quadrant code with 256 bytes in length is obtained. Experiments are carried on the database of 1000 images of 100 palms. The result shows that the recognition rate could reach 99.95% at given threshold. Compared with the traditional recognition algorithm based on the palmprint texture feature,this method has higher recognition rate.

This paper presents a new approach to real-time robot localization using kernel principal component analysis (PCA) regularization. The proposed algorithms are formulated as a semi-supervised learning during offline training. Firstly,sparse area features are extracted from the images captured by the camera mounted on the robot which moves along a predetermined path,and labeled a part of the data with their coordinates. Then,the coordinates of the unlabeled data are estimated by least squares with constraint of regularized low dimensional visual manifold in kernel PCA. In online localization stage,harmonic functions are employed to predict new data coordinates so that the real-time robot localization can be implemented using uncalibrated monocular vision. A series of experiments manifest that the proposed algorithms can outperform other conventional methods with low computational complexity,high localization accuracy and well real-time performance,so as to meet the real-time application requirements of industrial robots and medical service robots.

In order to solve the problems of differences in scale,rotation,grayscale and 3D viewpoint,and achieve robust scene matching during electro-optical imaging terminal guidance,a new feature descriptor based on uniform patterns is constructed and a new approach based on the descriptor and maximally stable extremal regions (MSER) is proposed. It is steps of realizing the method that,the MSER features of reference image and real-time image which are scale and affine invariant are extracted respectively;rotation and grayscale invariant description based on uniform patterns are performed. The matching MSER features between the two images are obtained based on Euclidean distance ratio criterion;epipolar geometry of the two images is estimated by applying random sample consensus (RANSAC) method to the centers of gravity of the matching MSER features. Simulation results show that the proposed method provides robust scene matching during electro-optical imaging terminal guidance and is more robust than traditional methods.

A dual-core photonic crystal fiber based on total internal refraction and photonic bandgap effect simultaneously is proposed,and its coupling properties are investigated by use of a full-vector finite element method. It is found that the coupling between the two cores of this photonic crystal fiber is different from that of other fibers based on single light-guiding mechanism. This fiber presents novel phenomena such as alternative cutoff of odd and even supermodes,existence of coupling length maxima and so on. The resonance of high-index inclusion between the two cores plays an important role in the coupling. The coupling length of the fiber can be changed significantly by tuning the sizes of air holes and distance between two air holes,and the locations of coupling length maxima can be shifted by adjusting the refractive index of high-index inclusion.

Using photonic bandgap of photonic crystals (PC) and the grating diffraction effect can improve the efficiency of the light from the light emitling diode (LED),it can expand the application scope of the LED. PC with square lattice of cylindrical unit cells are fabricated in GaN layer of GaN-based blue LED,the light extraction efficiency of GaN-based blue LED influenced by random perturbation of structural parameters are studied by finite-difference time-domain method and its mechanism is analyzed by the bang gap theory.

The band structure of two-dimensional photonic crystals consisting of the silicon (Si) dielectric cylinder square lattices is calculated by using plane-wave expansion method for the TM mode. Photonic crystal microcavity structure is designed. The defect-state field of the microcavity is simulated by finite-difference time-domain (FDTD) method,so the mode field distribution of defects is obtained. The thermal expansion and thermal-optic effect of silicon is taken into account,the resonant wavelengths of the microcavity are also calculated by FDTD method under different temperature. The results indicate that the resonant wavelength increases linearly while the temperature rising. The wavelength shift is 6.7 pm/℃. This characteristic of photonic crystal microcavity can be used for temperature sensing,which has a certain degree of practical significance.

A non-invasive in vivo monitoring method of tissue thermal coagulation based on optical tomography was proposed. The nonlinear multi-parameter optimization algorithm in the new reconstruction method was proposed,which was not based on the calculation of Jacobian matrix. N-decimal system parted coding operator genetic algorithm was used as optimization algorithm. The new reconstruction method could improve the reconstruction speed,avoid the ill-conditioned problem and calculation error of Jacobian matrix. A simplified region of interest model of thermal coagulation was given,which came at the least price of reduced precision. The monitoring method was proved by the experiment of egg white. The curves,reconstruction images and clinic significance were studied. It can be concluded that the reduced scattering coefficient image,got by optical tomography,can be used to evaluate the process of thermal coagulation non-invasively.

Optical trap stiffness of the optical tweezers must be accurately calibrated,before it is used to measure the mechanical characteristics of submicron particles or biological macromolecules. It is very important to choose a precise calibration method for exact measurement. With Monte-Carlo method,the signal sequence of displacement varies with time during five seconds for a particle in optical trap is simulated,and the simulative sampling frequency is 105 Hz. The optical trap stiffness is calibrated by three thermal-noise-driven analysis methods based on the experimental data in the condition of different noise levels and optical trap deviations. The results show that the ideal errors are all less than 2.5% for the three methods. The errors introduced by optical trap deviation can be eliminated when we calibrate the trap stiffness with the new coordinate of the particle′s displacement sequence,which is the difference between the original coordinate and its average. The mean square displacement method (MSDM) has a better anti-noise ability than the Boltzmann distribution method (BDM) and power spectrum method (PSM).

Introducing Lindhard potential to describe crystalline undulator radiation,the particle motion equation is reduced to the Duffing equation with a hard-spring properties in the classical mechanics frame and the dipole approximation. The main resonance and the super-harmonic resonance are analysed by the multi-scale technique;the nonlinear behaviours on a particle motion are discussed near resonance line;the critical parameter ac and system stable condition are derived. Because the critical condition is related to the parameters of the system,then these parameters are regulated suitably,an instability can be avoided in principle.Thus the effective output of X-laser or γ-laser can be assured. The theoretical analysis is provided to obtain the short wavelength laser.

Analysis of the optical characteristic on the filtering plane of the projection system based on grating light modulators (GLM) illuminated by extended light source is the key section of the optical information processing. The optical characteristic on the filtering plane of the projection system illuminated by a laser facular of certain size is analyzed using the theory of partially coherent light and the numerical simulation. The result shows that the diffraction light intensity distribution on the filtering plane is the convolution of the squared Fourier transform of the modulator′s transmittance function and the geometric projection of the laser facular size on the filtering plane. The diffraction order extends on the filtering plane,and the aliasing phenomenon appears that through the distance between the filtering plane and the modulator increasing while the degree of aliasing decreases. The relevant experimental system is constructed and the diffraction pattern on the filtering plane is obtained. The experimental results accord with the theoretical analysis. In the end,we propose that a converging lens set between the modulator and the filtering plane could reduce the optical dimension of the system,and a method for improving the effect of system information processing.

The key dwell time solution algorithm in ion beam figuring (IBF) was investigated to get the high-precision optical surface. With the principle analysis of the IBF process,the deconvolved process of dwell time solution was transferred to a dwell time matrix equation. Except the regularization weight faction,another variable,that is extra removal amounts,was introduced to the dwell time matrix equation to expand the freedom of dwell time solution,so the dwell time solution could be found with larger range. With the Gerchberg band limited extrapolation algorithm for initial surface expansion,the high-precision surface could be gotten within full aperture range. The example calculation of 50 mm planar optical surface shows that the final surface precision was reduced to:rms is 0.001λ,PV is 0.0115λ from the initial rms of 0.5747λ,PV of 2.3706λ(λ=632.8 nm). The conclusion is that the perfect dwell time solution could be gotten from the revised dwell time matrix equation and initial surface expansion,and so it can be used to instruct the IBF process perfectly.

As a deterministic magnetically assisted polishing method,magnetorheological finishing (MRF) has the ability to produce optical surfaces with high from accuracy,high efficiency and low sub-surface damage. The principle and method of MRF process are introduced and the key techniques required to implement a MRF process are also discussed. To demonstrate a MRF process,one K9 flat (80 mm in diameter) is polished with KDMRF-1000F polishing machine and KDMRW-1 water based magnetorheological (MR) fluids. Through one MRF iteration (4.39 min),its form accuracy peak-to-valley (PV) error is improved from initial 0.144 λ to final 0.06 λ (λ=632.8 nm),root-mean-square (RMS) is improved from initial 0.031 λ to final 0.01 λ,surface iterative convergence ratio is 2.81 and roughness RMS is 0.345 nm. The result shows that MRF is a deterministic process,which results in high form accuracy,surface roughness and high efficiency.

A micro-and nanofiber pen (MNFP) direct writing technique for fabricating submicron lines is presented. Contact exposure is adopted during micro-and nanofiber pen scanning on the photoresist film. A two-step processs for fabricating the sharp and short MNFP is established by flamed-heated drawing and wet etching. The MNFP direct writing experiments are performed. The resolution of 200 nm line width is obtained,which is thinner than half of exposure wavelength (442 nm). The experiment results also show that MNFP direct writing can provide various widths of line by changing the radiation power.

Based on the thermal optical analysis,the glass thickness of optical window under the complex environment is optimized. Intensity and the thermal environment of optical window is analyzed. steady-state temperature field is calculated. By mapping the temperature field to structural model,the deformation of optical window under the force-thermal coupling condition is calculated. Combinating refractive index gradient analysis and glass surface change of optical window,thermal optical analysis is carried out. When the glass thickness is different,the optical path in root mean square error(RMS) of optical window with diameter of 350 mm is calculated. Thickness of the optical window is determined as 18 mm. The results show that the optical window can not only meet the strength and reliability requirements,but also meet the optic index in the effective optical aperture. These results provide the guidance for the optical window design.

The bandwidth of s-polarization and p-polarization will separate when the narrow-band thin-film filter is in tilted incidence,which will limit the tunable range of the filter. The phenomenon of the polarization bandwidth separation and its relation to the mirror layers of the filter are analyzed. A method about eliminating the polarization bandwidth separation is also presented. According to this method,a former designed 100 GHz dense wavelength division multiplexing four-cavities angle-tuned narrow-band filter is improved. The simulation results prove it can eliminate the polarization bandwidth separation and enlarge the tunable range.

A novel 128×128 elements liquid crystal lens array with tunable focal length was analyzed and fabricated by using frequency drive instead of voltage drive. The top electrode was designed as circular array electrode. As the electric field was inhomogeneous in circular unit,the rotation angle was different in liquid crystal layer. Then the gradient refractive index was formed,and the optic in the circular unit was convergent. The effect about focal length of liquid crystal lens array with different frequencies was analyzed. The focal length range of liquid crystal lens array was 20-600 μm. The focal size was 10 μm. The response time was sub-microsecond. The liquid crystal lens array driven by frequency can be got in this way. So the operating voltage of liquid crystal lens array was lower,and the response time of liquid crystal lens array was quicker.

By mean of focused ion beam (FIB) etching,the samples were prepared on a 120 nm-thick gold film. The comparison of optical transmission shows that the circular hole arrays,which possesses the six-fold rotational symmetry and central symmetry,has higher transmittance than the two periodic structures′. Its peak efficiency is about five times larger than that of the square hole arrays. It can be attributed to the stronger constructive interference of multiple scattered waves in a higher symmetrical hole structure. The position of the enhanced peak for the circular hole arrays locates in the visible region,while that of square hole arrays is in the infrared region.

The absorption and emission characteristics of single plasma channel produced by femtosecond laser pulse in air have been investigated theoretically. Analytical expressions of Rosseland mean absorption coefficient and radiant energy fluence rate are deduced. It is found that our analytical results are consistent with data from TOPS opacities database. The dependences of absorption and emission characteristics on initial laser parameters are studied. Calculation of such quantities for air plasma channel induced by laser pulse with 800 nm central wavelength and 40 fs pulse width is carried out. Results indicate that,in the case of single filament,the average Rosseland mean absorption coefficient is 0.0270 cm-1,and total radiant energy fluence rate reaches 7.87×1010 W/m2. Incident fs laser with shorter pulse width and longer wavelength furns out advantage to producing weak absorbing and strong radiative plasma channel.

The result of theoretical calculation shows that fractional stimulated Raman adiabatic passage can create maximal coherence between the hyperfine levels in a Pr:YSO crystal. A probe pulse interaction with the atomic coherent system leads to efficient generation of a Raman signal field. The influence of some factors on the signal is discussed also,these theoretical results provide useful reference for the related experimental investigation.

When the two middle levels in a four-level ladder atom are coupled with a ground and a excited levels by the same vacuum radiation fields,respectively,there are two kinds of vacuum-induced coherence (VIC):V and Λ-type VIC;due to the quantum interference effects between the spontaneous decay channels. The effects of the VIC on the electromagnetically induced single- and two-photon transparency are studied by the semiclassical theory,respectively. The Λ-type VIC enhances the two-photon absorption,but has no effect on the single photon absorption;the V-type VIC suppresses the single and two-photon absorption.

The squeezing properties of a two-mode field initially in a coherent state resonantly interacting with a three-level V-type atom are investigated by means of the quantum theory and numerical calculations. The dependence of the squeezing on the average photon number of the cavity mode,the coupling constant and the interaction time is discussed for three cases:1) no state-selective atomic measurement;2) direct state-selective atomic measurement;3) state-selective atomic measurement after the application of a classical field. It is show that the squeezing increases with the average photon number of the two cavity mode,and it is greatly enhanced if the atom is state-selectively measured even for the case of low photon number. It is concluded that the maximal squeezing is approximately 75% for all the considered cases.

The absorption spectra and fluorescence spectra of lactobacillus plantarum are measured and studied by spectral analysis technique,and the results will be applied to the study and classification of probiotic bacteria. The results show that lactobacillus plantarum obvioushy absorbs ultraviolet rays and emits obvious fluorescence. The peak of aborbtion spectra is at 215 nm,and there is a shoulder peak at 280 nm which disturb the absorbtion spectra. The studies of the spectra show relevant information in cells about lactobacillus plantarum. The relations between fluorescence intensities and the concentrations are also studied and the change law of intensity with increasing concentration is found. The functions of data fitting based on the law are shown.

The derivative method can correct baseline effects but also add noise to it. The empirical mode decomposition (EMD) method was proposed to get the pretreatment of near-infrared (NIR) spectrum. Herein,the first derivative NIR spectrum of tobacco was served as the target and the application of EMD in NIR spectrum pretreatment was studied. Experimental results showed that the result after de-noising with EMD was satisfactory. The correlation ratio of the prediction set was improved from 0.9705 to 0.9832,and the RMSE reduced from 0.5606 to 0.3310. And this method obtained a better de-noising effect compared to wavelet transform method. It is concluded that EMD is a useful method to eliminate noise of NIR signals,which makes the final model more representative,stable and robust. EMD provides a new method for near-infrared spectrum pretreatment.

1064 nm,532 nm frequency-doubled antireflection coating with out buffer layer or with different buffer layers were fabricated by using electron beam evaporation technique on LBO. The optical property,adhesion and laser-induced damage threshold (LIDT) were investigated by Lambda900 spectrometer,MTS nano Indenter and Q-switched pulsed laser,respectively. The results showed that the reflectance of all samples was below 0.1% and 0.2% at wavelength of 1064 nm and 532 nm,respectively. Comparing with the sample without buffer layer,the critical adhesion of the sample with buffer layer of Al2O3 was increased by 43% and that of the coating with buffer layer of SiO2 was improved significantly. LIDT of the coatings were improved by using buffer layer of SiO2 and that of the coating with buffer layer of Al2O3 was decreased.

The optical properties of Al2O3 films grown by atomic layer deposition were investigated. Trimethylaluminium (TMA) and water vapour (H2O) were used as the chemical precursors to deposit Al2O3 films on glass substrates at temperature of 250 ℃ and 300 ℃ respectively. Characterization of the films such as optical properties,surface morphological image and microstructure were performed by using spectrophotometer,X-ray diffraction (XRD),X-ray photoelectron spectroscopy (XPS),scanning electron microscope (SEM) and atomic force microscopy (AFM).The results show that both the as-deposited and annealed A12O3 films are amorphous. The surface roughness is as low as 1.2 nm while the packing densities are larger than 0.97. Al2O3 films by this technique exhibit good optical properties with low absorption in the spectral region from mid-ultraviolet to near-infrared. This study indicates that Al2O3 film deposited by ALD is applicable for optical coatings of the materials with midde and low refractive index.

Silver films bedded and covered Al2O3 were prepared with five different deposition rates:0.44,0.30,0.18,0.08 and 0.04 nm/s. The reflectance spectra indicated the sample with a deposition rate of 0.18 nm/s had the highest average reflectance. X-ray diffraction (XRD) spectra of the five samples were obtained by XRD,which showed silver (111) was the preferred orientation. The sample with the deposition rate of 0.18 nm/s had the highest intensity of diffraction peak,the narrowest full width at half maximum (FWHM) and the biggest average grain size,which totally meant the sample had a best crystallinity. Samples with faster or slower deposition rate would cause low level crystallinity and resulted in the increase of extinction coefficient and decrease of reflectance. In our experimental conditions,it is suggested the best deposition rate is around 0.18 nm/s,which can lead to the best crystallinity and average reflectance. The result is different from the opinion which originally regarded the quality and reflectance of silver films would be better with faster thermal evaporation deposition rate.

Based on the biaxial birefringent model,the structural parameters of thin film,including the principal refractive indices N1,N2,N3,the thickness d and the column angle β were determined by fitting the measured transmittance spectra for two polarizations at the normal and oblique incidence. With the glancing angle deposited technique,the sculptured tantalum oxide thin films were deposited by reactive electron beam evaporation. The structural parameters were extracted by fitting the measured spectral transmittance curves at the incident angle of 0,20°,30°,45° and 60° with the simulated annealing algorithm. Besides,the tilted nano-column structure,the thickness and the column angle were obtained with the cross section of thin film,examined with scanning electron microscope. The results show that the structure parameters of sculptured thin film can be extracted from the transmittance spectra.

LaAlO3 thin films were fabricated on p-Si (100) substrates by using radio-frequency magnetron sputtering deposition method at room temperature. Then the samples were annealed at 800 ℃,900 ℃ and 950 ℃,respectively. The structural,morphological and optical properties of LaAlO3 thin films annealed at different temperature were investigated separately by X-ray diffraction (XRD),atomic force microscopy (AFM) and fluorescence spectrophotometer. The results of XRD and AFM show that annealing at higher temperature can improve the crystalline quality of the films. The films changed gradually from amorphous to crystalline above 900 ℃. Two emission peaks located at 368 nm and 470 nm in photoluminescence (PL) spectra are observed,respectively. The intensities of PL peaks increased with increasing annealing temperature. According to the absorption spectra and the calculated defect energy levels of the LaAlO3 films,it can be proposed that the 368 nm UV emission originates from the defect energy level of oxygen vacancies to the top of valence band and the 470 nm blue emission is derived from electron transition between the energy level of negative electricity AlLa anti-site defects and the top of valence band.

The phenomenon of pulse self-compression in temperature gradient controlled filamentation is demonstrated. 2.0×105 Pa argon gas sealed in quartz tube as the propagation medium,heating up at the focus,forms temperature gradient because of the heat conduction. At 25 ℃,the input pulse energy is 0.8 mJ,the output pulse self-compresses to 17 fs without dispersion compensation,and the Fourier transform limit pulse is 5.5 fs. When the energy is up to 2.7 mJ,and temperature gradient at the center is 450 ℃,the output pulse self-compresses to 19 fs and the Fourier transform limit pulse is 14.5 fs. The energy of self-compression increasees by nearly 2 mJ through temperature control,achieves the process from self-compression to single-filament pulse broadening and then multi-filamentation.

A third harmonic generation method using dual non-collinear laser filaments of equal wavelength was applied to experimentally study the spectral properties of the on-axis third harmonic generation in nitrogen gas. The filaments were generated by non-collinear focusing two beams with 820 nm of central wavelength,70 fs of duration,10 Hz of repetition,3 mJ and 7 mJ of single pulse energy into a nitrogen gas cell,using a concave mirror. When the two laser beams were overlapped both in time and space,the intensity,central wavelength and spectral width of the harmonic signal were found to be strongly dependent on the gas pressure and time delay of the two fundamental beams. The enhancement,spectral broadening/narrowing of the third harmonic spectra were observed when changing the time delay of the two fundamental beams. When the pressure of nitrogen gas about 0.16 MPa,and the inducing beam advanced the stimulating beam of about 20 fs,the on-axis third harmonic signal on the stimulating beam side was enhanced of about 60 times,while its spectral width was broadened from 15 nm to 25.8 nm,and 100 THz in frequency domain.

Based on the ray-tracing theory,a calculation model for X-ray transmission in a tapered X-ray capillary was set up. Using the calculation model,systematic theoretical studies on the transmission characteristics of a tapered capillary were performed. Calculating the intensity distribution,the conclusion was got that the size of X-ray source and the entrance diameter of the tapered capillary affected the form of intensity distribution. We got the change rules of power density gain K with R0 and f2. Taking the equivalent distance Leq as a standard,the optimal design of tapered capillary was discussed.