The atmospheric qualities of Olympic national stadium were measured by using the fine particulate meter (FPM),tapered element oscillating microbalance (TEOM,with a PM10 cutting head),visibility sensor and meteorological analyzer during Beijing 2008 Olympic games from 8 to 24 August,2008. The variation trend of diurnal average of particle number concentration showed that the nucleation mode (5-20 nm) was closely related to the nucleation process,and the concentration curve was unimodal. Atiken mode (20-100 nm),with curve of three peak values,was stronger influenced by human activities and growing process of nucleation mode. Accumulation mode,with a tiny trend for its diurnal average particle number concentration,was strongly affected by the weather conditions such as rain. The visibility,the particle number size distribution in rainy,haze and sunny weather conditions were also summarized. The conclusion that scavenging action of rain to the particles had close relation with particle size,and lower visibility in haze day was caused by the scattering excitation of accumulated mode particulate. Mass concentration of PM10 was calculated using the data of particle number concentration,and it showed a good coincidence with PM10 directly measured by TEOM. The correlation coefficient could achieve 86.1%.

Combined with the atmosphere extinction data when the lidar was operated,N2 vibrational Raman scattering signals of detecting atmosphere CO2 Raman lidar system were used to determine the lidar geometric form factor,and analyze and estimate the influence of aerosol wavelength exponent changes on geometric form factor determination. The results show that the aerosol wavelength exponent would have influenced the determination of geometric form factor with vibrational Raman signals. When the aerosol wavelength exponent was determined by other experiments,determination of geometric form factor for Ramon lidar with vibrational Raman scattering signals is simple,convenient and credible.

Time delay of atmospheric aerosol particles and its effect on the path difference of laser were discussed. Using two-frequency mutual coherence function,the equation of path difference in the discrete random medium was obtained and the relation between the path difference with the number density and diameter of particle was established. A new method for calculating the path difference caused by time delay of aerosol particles was presented,and the path difference was calculated by using typical modes provided by optical properties of aerosols and clouds (OPAC) package in satellite laser ranging. Results show that,when the wavelength of laser is 1064 nm and the mode radius of aerosol particles is more than 0.25 μm,the path difference is approaches 4.6 cm with the mode radius increasing;when the millimeter and even sub-millimeter precision of satellite laser ranging is required,the path difference induced by time delay of atmospheric aerosol particles should be corrected.

A design scheme of holey fiber with the combination of rectangular lattice and a pair of large-diameter holes in the cross section is proposed,and wideband stable birefringence beat length can be obtained via optimization of the structural parameters. Finite-difference beam propagation method is used to calculate the modal birefringent characteristics of the holey fiber. The influence of different structural parameters on the modal birefringence is analyzed. The calculation suggests these two asymmetric structures can provide positive and negative birefringence respectively. And their interaction can control the variation slope of birefringence over wavelength. Then linear relation of proportional variation between the birefringence with wavelength can be achieved in some given bandwidth,so that wideband stable beat length can be obtained. By optimizing the lattice pitch and the diameter of air holes,stable beat length with the value of 10 mm at 1310 nm and 1550 nm is designed with relative bandwidth more than 12%. This optimal fiber is very suitable for make wideband fiber-optic wave-plate integrated in all-fiber large current sensor.

Micro-bend long period fiber gratings (MBLPFG) are presented by pressing a single mode fiber from double sides with two identical grooved plates whose pitch is 600 μm and teeth width is 200 μm. Because the teeth width is smaller than half pitch of the grooved plate,deeper micro-bend modulation in fiber can be made,and so a bigger “AC” cross-coupling coefficient can be achieved. By measuring the transmission spectra of two micro-bend long period fiber gratings with lengths of 6 cm and 12 cm,respectively,the relations between peak loss,out of band loss,full width at half maximum (FWHM) of loss ratio spectra with applied pressure for different grating length are investigated. For the micro-bend long period fiber grating of 12 cm length,near the first saturation pressure,the peak loss reaches 19.2 dB,the FWHM is 20 nm,out of band loss is only 0.26 dB. After over coupling out and back three times,a peak loss of 34 dB is achieved. Then,through analysis from theory and experimental data,it is found that the “AC” cross-coupling coefficient grows linearly with applied pressure,when the pressure on the fiber is less than saturation pressure.

The influence of the modulation index of the radio frequency (RF) signal on the optical carrier on the relation between power of the carrier component and that of the sideband component of the optical millimeter-wave signal generated by single sideband (SSB) modulation in the radio over fiber (ROF) system is theoretically and numerically investigated. In order to address the problem that when the carrier component is much larger than the sideband component in the optical SSB millimeter-wave signal that the receiver sensitivity of the radio over fiber (ROF) system is relatively low,the determinant of the power of carrier component and sideband component is analyzed. It is shown that an optimum RF modulation index can bring on a balance between the powers of these two components. It is verified by simulation results that the optimum RF modulation index can make the power of sideband equivalent to that of carrier component,thus results in the best receiver sensitivity of the radio over fiber system.

Based on the basic principle of fiber optical Bragg grating (FBG) strain sensing and the basic theory of viscoelastic mechanics,a simplified time-dependant optical-mechanical transformation equation for FBG sensors is established. With the viscoelastic mechanic behavior of encapsulation matrix and optical fiber core being neglected and the elastic-viscoelastic mechanic coupling mechanism among environment-encapsulation matrix-adhesion layer-optical fiber core being taken into account,the equation hereby established contains all the characteristic geometric and mechanical parameters of a sensor,and can greatly simplify the process of optical-mechanical transformation analysis,thereby more reliable and less complicated for long-term performance analysis of FBG sensors when applied to health monitoring of large project.

Single-carrier frequency domain equalization (SC-FDE),as a mature technique in wireless commutation,is widely researched for signal equalization and compensation utilizing high speed electronic devices such as digital signal processor,A SC-FDE technique in optical communication system for received signal dispersion compensation is proposed and demonstrated. After 50 km,80 km,100km transmission for a 10 Gb/s amplitude shift keying (ASK) single sideband (SSB) signal on a single mode fiber,the dispersion of optical signal is effectively compensated by adopting SC-FDE technique. The SSB signal is generated by a dual-arm Mach-Zehnder modulator cascading a phase modulator based on Hilbert finite impulse response digital filter. The results demonstrate that the eye opening and the clock recovery is improved,and the effect of compensation is enhanced as the transmission distance increases in proposed SC-FDE model. At last,the SSB modulation location for achieving the best SC-FDE effect is also obtained.

In view of the speckle noise in the synthetic aperture radar (SAR) images,and based on the Contourlet′s advantages of multiscale,localization,directionality,and anisotropy,a new SAR image fusion segmentation algorithm based on the persistence and clustering in the Contourlet domain is proposed. The algorithm captures the persistence and clustering of the Contourlet transform,which is modeled by hidden Markov tree (HMT) and Markov random field (MRF),respectively. Then,these two models are fused by fuzzy logic,resulting in a Contourlet domain HMT-MRF fusion model. Finally,the maximum a posterior (MAP) segmentation equation for the new fusion model is deduced. The algorithm is used to emulate the real SAR images. Simulation results and analysis indicate that the proposed algorithm effectively reduces the influence of multiplicative speckle noise,improves the segmentation accuracy and provides a better visual quality for SAR images over the algorithms based on HMT-MRF in the wavelet domain,HMT and MRF in the Contourlet domain,respectly.

For an omni-directional stereo vision system,two omni-cameras are assumed to have a common optical axes,i.e. co-axis stereo. The epipolar geometry of the ideal configuration is linear along radial direction,which simplifies correspondence search. However,it is often violated in practice due to misalignment between optical axes,which reduces the measurement accuracy. In order to compensate this misalignment,a generalized rectification algorithm for omni-directional stereo system is proposed. The essential matrix is derived and computed for an arbitrary omni-directional stereo configuration based on Taylor model. Using the one-to-one corresponding relationship between epipolar curve and its tangential space,the system is rectified to the direction of the line connecting two cameras′ centers. The corresponding points are constraint to the radial line,and image-resample makes them lie on the same scan column. The proposed algorithm is only performed on image plane. Finally,simulation and experimental results illustrate the effectiveness of the algorithm.

An efficient method to acquire multi-view parallax images for multi-view auto-stereoscopic display from two parallax images is presented. Firstly,the feature matching of the two given parallax images by using SIFT matching algorithm is done and the dense matching the images is accomplished after the propagation of the SIFT matching points. Then,the parallaxes are approximately calculated by the coordinates of the matching points to generate the depth map of the left image. At last,a method using an original image and its depth map to acquire multi-view parallax images is proposed. Good stereoscopic images are presented on an auto-stereoscopic display device after the parallax images were synthesized.

An efficient method is proposed to track the motion of single molecules fast and accurately. Single molecule localization is realized by image de-noising and applying a centroid algorithm based on Gaussian mask. Then the corresponding locations are linked into trajectories taking into consideration the characteristic intensity and actual displacement between subsequent frames. The method is quantitatively evaluated by using simulated sequential images at variable signal-to-noise ratios (SNRs). Compared with two-dimensional direct Gaussian fitting which is considered to be the best technique for deriving centers of single molecules,the method proposed here not only shortens the computational time to 1/10 but is also superior over the whole range of SNRs yielding lower bias and standard deviation. Particularly,at low SNRs,where the two-dimensional direct Gaussian fitting doesn′t work properly,the center coordinates can still be reconstructed. A speed of 4-5 frame/s (one million pixels per image) has been achieved in the current study on a commercial personal computer.

The field of view of the laser warning system is an important target of its performance quality. The laser spectrum based on the non-scanning Fourier transformation interferometer in the experiment foundation is imsestigated,The path difference function about the incident angle and the coherent position′s is calculated for any angle laser incidences in the field of view in 60°. The two non-scanning Fourier transformation interferometers method is proposed to solve under the vertical angle. According to the simulation experimention,it is found that the interference fringes changes dense,bright band thinning,and wavelength faraway when the incident angle′s changes. The experiment proves that the interference fringe computation and the simulation result is coincident,the laser warning system may detect the laser spectrum information effectively in the wide field of view,and the highest precision of laser incidence direction may reach 1°.

By introducing phase and fringe technique to optical 3-D object measurement,handheld phase target is proposed. With vision measurment technology,any contacted point of measure object can be measured directly by the target. In addition,the distance between control points of handheld phase target and measurement point ,and the coordinates of the probe of target coordinate system can be obtained by adopting phase technique and the full optical field fringes analysis. In the same way,3-D coordinate of measurement point on the object can be calculated accurately. Error analysis about 3-D coordinate of measured points is done and the corresponding distance excursion is also obtained. The accurate measurement result can be obtained in the experiments so that the analysis is proved to be right.

In the high-precision measurement system,the charge coupled device (CCD) nonuniformity will give a greater margin of error to measurement results. According to the characteristic of noise leading to the image pixels nonuniformity,the corresponding image model is established. According to the traditional two-point linear correction method,an adaptive correction method is put forward,in which the Hilbert-Huang (HHT) filter theory is applied. With the scale decomposition of image sequences on the time domain and the corresponding statistics calculation,the offset and gain coefficients in CCD image are obtained. In experiments the high speed area array CCD is adopted to acquire images with the circular facula launched by the laser,and the algorithm is verified by calculating the facula central coordinates of the image. The results show that the algorithm can correct pixel nonuniformity effectively. The algorithm proposed is better than the algorithm for nonuniformity correction using linear model. The experimental result shows the superiority of the algorithm.

The surface distortion and tube length changes of three-line CCD camera at different temperatures were analyzed with finite element model. the Zernike coefficients from finite element model were put into optical-design software CODE V to calculate the decline of modulation transfer function (MTF),and the 2 ℃ temperature indicators were made by optical parameters. Thermal optical experiment was done for a variety of temperature levels on the three-line CCD camera,and the measured static transfer function of the laboratory are at or close to target 0.2. The MTF of experiment was measured and compared with the result of theoretical analysis to affirm the temperature indicators and temperature control means were reasonable.

On the basis of summing up conventional testing methods for convex aspheric surfaces,a novel method for testing convex aspheres by subaperture stitching interferometry (SSI) is proposed. A sphere mirror is used as the reference surface,and the phase distribution of each subaperture can be measured by the digital wavefront interferometer. The full surface map is obtained by stitching five subapertures which have been subtracted the theory wavefront error from phase datum and eliminated the translation errors. The basic principle and theory of SSI are researched,and the stitching software and prototype for testing of convex aspheres are devised and developed. A convex SiC asphere with the aperture of 140 mm is tested by this method. As results,the PV and RMS of the surface error after stitching are 0.274λ and 0.024λ (λ=632.8 nm),respectively. For the validation,the asphere is also tested by null compensation,the synthesized surface map is consistent to the entire surface map from the null test,and the difference of PV and RMS error between them is 0.064λ and 0.002λ,respectively. So it provides another quantitive measurement for testing convex aspheric surfaces.

Single-frequency radiation is often considered to be indispensable for coherent beam Combination (CBC) of fiber amplifiers in master oscillator power amplifier (MOPA) configuration. Nevertheless,the single-frequency radiation limits the output power of each single fiber gain due to low stimulated Brillouin scattering (SBS) threshold. Wide linewidth and multi-wavelength radiations are two effective approaches to mitigate SBS effects in fiber amplifiers. Coherent beam combination of three wide-linewidth fiber amplifiers and three multi-wavelength fiber amplifiers are both experimentally demonstrated using stochastic parallel gradient descents (SPGD) algorithm. The experimental results show that single radiation is not indispensable for CBC in MOPA configuration,the application of wide-linewidth and multi-wavelength amplifiers present the potential in achieving a much higher output power in MOPA configuration.

Typical intensity distribution of laser beam is Gaussian profile. To improve the energy efficiency of the laser systems,it is necessory to convert Gaussian profiles or quasi-Gaussian profiles into uniform profiles. Based on the energy conservation and constant optical path-length principle,the spatial beam shaping system with aspheric lenses is analyzed in detail and the phase distribution for the optics is derived. In addition,a quasi-flattop intensity distribution is realized from the quasi-Gaussian beam by phase only liquid crystal spatial light modulator. The phase distribution of the shaped beam is measured by a wavefront sensor.

The four-mode laser gyro′s null shift is very complex under the high-low temperature process. It often vibrates when temperature changes linearly,which is a very difficult problem that cannot be explained and solved. Beam intensity changing along with temperature is simulated by changing the discharge current at room temperature,and the null shift also vibrates. So it can be concluded that temperature change induces beam intensity change,and then the null shift vibrates. If beam intensity of four-mode laser gyro can be kept constant in the high-low temperature,the null shift vibration will be effectually controlled. The conclusion is proved by the high-low temperature experiment with intensity stability.

Line-shaped image features are widely applied in many cases and the measurement is required as fast as possible. However,a traditional method (normalized cross correlation operator,NCCO) which is used for pattern matching in microscopic vision needs lots of calculations for a considerable time. Inspired by this,some research work about pattern matching of geometric image features is presented. Firstly,a probability distribution of image features is worked out to describe functions with the operator NCCO through matching two binary images. Secondly,the formulas with linear image parameters are derived and certified by designing special templates and line-shaped features. Based on this model,a measuring algorithm of line-shaped image features is proposed. The simulation studies of the image mixed with moderate-intensity noise conclude that the algorithm accuracy of angle α is up to 0.24°-0.98°. Finally,the algorithm is applied in a hybrid microassembly work-bench to measure the feature′s position. Experimental results show that the algorithm based on NCCO mathematic model is more precise than traditional method in real-time process.

Series of GeS2-Ga2S3-KCl chalcohalide glasses were prepared by traditional melt-quenching method. Thickness,density,refractive index,visible/near-infrared absorption and infrared transmission spectra were adopted to the analysis of the allowed direct interband optical transitions of optic gap with Tauc equation. The results show a good physical performance as it possesses a wide glass-forming regions of GeS2-Ga2S3-KCl pseudo-ternary glass system. With the increasing of KCl content,there were significant decreases in glass density and refractive index,but there is a significant augmentation of optic band gap. Others,some corresponding changes of glass host structure were deduced from FTIR and Raman spectra,as that the IR optic spectra was improved,just like the Raman spectrum changed by steps,IR absorption cutting-off edge red-shifted with regular. Based on the analysis of KCl adding in the glass host,a quantitative description was given about the correlations between IR multi-phonon absorption and fundamental phonon-vibration,as it shows a deterministic dependence of the optic optical properties of chalco-halide glasses on glass host.

The Raman spectrums of new scintillation materials LaCl3 and LaBr3 single crystals in different temperatures for different surfaces are measured. Five of all six peaks of LaCl3 crystal and all six peaks of LaBr3 crystal are obtained. The Raman shift becomes smaller while temperature rises,and approximately can be fit to a linearity result. A polarizer is placed on the path of Raman scattering light,and no change can be observed while light propagates parallel to c-axis,while remarkable changes can be observed when light propagates perpendicular to c-axis.

A series of glasses with high Bi2O3 content of Bi2O3-B2O3-Ga2O3 ternary system were chosen and prepared by the conventional melt quenching methods. The densities,linear refractive indexes n0 and transmittance spectra of samples,and their relation with Ga2O3 content were measured. The third-order nonlinear-index coefficient n2 and the nonlinear absorption coefficient β of glasses were investigated at 800 nm by Z-scan technique using Ti:sapphire femto-second laser pluses. The conclusions were as follows:The values of n0 and n2 in glasses increase with increasing the Ga2O3 content. The values of n2 and β at 800 nm in the sample which had the largest refractive index in all samples are equal to 3.331×10-18 m2/W and 0.695 cm／GW,respectively. All the results show that these glasses are potential materials in the application to third-order nonlinear optical field.

Structure parameters of the slow light in the photonic crystal coupled resonator optical waveguide have been investigated. It is found that cavity distance n,filling factor r/a and size of the defect rod rd are the most significant factors affecting the transmission properties of the slow light guided mode in the photonic band gap. With the increase of cavity distance,the group velocity vg of guided mode decreases rapidly. When filling factor and defect rod size increase,the guided mode shifts towards a lower frequency with vg decreasing simultaneously. When the filling factor and defect rod size increase to a respective certain value,vg reaches a bottom value. And as r and rd exceeds the above certain value,group velocity of the guided mode will increase. By choosing appropriate structure parametersm of n=6,r=0.22a,rd=0.12a,it is obtained that the maximum value of guided mode vgmax=1.93×10-3 c and vg<10-4 c at the band edge in the photonic crystal coupled resonator optical waveguide. These results indicate that effective control over the slow light in the photonic crystal coupled resonator optical waveguide could be realized through basic structure design,which may offers significant support for design and application of functional devices based on photonic crystals.

Both of the fluorescence and polarization spectral characteritic of steady-state and polarized fluorescence induced by 407 nm laser of normal and the alcoholic whole blood are studied. By calculating the polarization degree and the rotation-relaxation time of the two blood cells,the depolarization effect of alcoholism blood is less than the normal one,but the rotation-relaxation time is opposite. The result is in accordance with the hemorheologic measurements. Because of alcoholism,viscidity of blood and the volume of erythrocyte become greater. The combined action of the two changes induces the regularity variation of fluorescence intensity,polarization degree and the rotation-relaxation time of the normal and alcoholism blood cells.

We evaluate the influence of water spray′s flow rates on the rate,the efficiency of laser-hard tissue ablation and the resulting surface morphology. Fresh bovine shank bone in vitro was used in the experiment. Light emitted from a pulsed CO2 laser with a wavelength of 10.64 μm and a repetition rate of 60 Hz was transmitted through an articulated-mirror-arm system and focused to a spot of which the diameter is about 400 μm on the bone sample surface directly. The radiant energy density was 26.5 J/cm2 and irradiation time was 10 s. A water spray system applied spray on sample surface with an angle of 45°during irradiation at flow rates of 0(without a water spray),0.26,0.5,0.6,0.7 and 0.9 mL/s. After irradiation,the morphological changes and microstructure of ablation craters were examined by stereoscopic microscope and scanning electron microscope (SEM) respectively. The ablation depth was also measured by optical coherence tomography (OCT). The result shows that the water spray has a profoundly influence on laser ablation rate and efficiency for hard tissue removal and the resulting morphology. Water spray not only can cool the tissue and reduce the thermal damage,but also can augment ablation rate and efficiency,and alter the surface morphology by optimal selection of laser irradiation parameters and water spray flow rate.

In order to obtain influence parameters of second-harmonic wave (SHW) conversion efficiency for negative-index materials (NIM) of SHW and positive-index materials of fundamental frequency wave (FFW),the rigorous formulation of SHW conversion efficiency had been deduced on the basis of the coupled-wave equations under the conditions of taking account of walk-off effect,phase mismatching capacity,and the approximation of slow-varying amplitudes for plane wave. The effects of phase mismatching capacity (PMC),intensity of FFW,and walk-off angle of SHW were researched by numerical simulation respectively. Results showed that the conversion efficiency of SHW (CESHW) gradually increased via increasing the intensity of FFW and that the CESHW gradually decreased via increasing walk-off angle and phase mismatching capacity when the intensity of FFW were very small. However,when the intensity of FFW was much large,the CESHW would become obviously periodic evolution via increasing the intensity of FFW. This research would provide a basis for investigating nonlinear theory of negative-index materials. Besides,the length of NIM plays the same as the intensity of FFW in the process of SHW conversion.

In order to implement multi-gray-level holographic storage using a binary spatial light modulator,a data page to store is divided into a series of equivalent binary data pages. The recording time is also split into a series of time slices corresponding to the binary data pages. During each time slice,a binary data page is uploaded by the binary spatial light modulator into the object beam which interferes with the reference beam. A series of holograms are recorded in the material. It is proved theoretically that the gray-level distributions of the reconstructed data page are equal to those of the original data page. An experiment of four-gray-level storage is carried out to verify its feasibility. The multi-gray-level storage method can enlarge the capacity of the stored data page. The dynamic range of the material is fully made use of. And the storage density and readout data rate are both improved.

8-12 μm infrared (IR) hybrid refractive/diffractive continuous zoom lenses is designed for the needs of target detecting/tracking system. The defects of conventional systems,such as being insufficient for achieving long focal length,large relative aperture,big zoom ratio,high imaging quality and simple structure,are solved in this system,which has the properities of large relative aperture,F=0.9,zoom ratio 11×,discernment with long focal lengths for tanks at about 1500 m distance. The optical system composes of seven pieces of Germanium lens. To correct chromatic and off axis aberrations,the system applies diffractive optical element (DOE) and aspherical surface. The modulation transfer function (MTF) is above 0.64 in all focal lengths at the spatial frequency of 17 lp/mm,which approaches the diffraction limit. The energy concentration ratio is greater than 82% in the 17.5 μm radius of sensing pixel. It shows that the optical system has good imaging quality and meets the needs of general requirements for the target detecting/tracking system.

A large relative aperture athermalized infrared optical system with wide field of view is introduced. The working wavelength is 8-12 μm;the full field of view is 40°;the effective focal length is 6 mm;the relative aperture is 1.25;the total optical length is 50 mm;and the back focal length (BFL) is 15 mm. It consists of a diffraction surface and two aspheric surfaces with a triplet structure,only using germanium and ZnSe. The system is simple,low mass and high image quality. The evaluation of the system is given in the temperature range of -80 ℃-200 ℃. The results show that the modulation transformation function (MTF) is near to 0.7 at the spatial frequency of 16 lp/mm and also near to the diffraction limit.

With the development of space technology,the optical system design must be satisfied with the lastest demand due to the ground sample distance (GSD) steadily improving. The issues of the optical system design is discussed,the space optical system design principle with large F number,long focal length is analyzed and a reflective optical system which is characterized by the spectrum band 500-800 nm,focal length of 7200 mm and F number of 14.4 is designed. The result indicates that the field angle reaches 1.6°,the ground width reaches 12.5 km and the graund sample distance (GSD) reaches 0.62 m at 450 km orbit,the quality of image approaches the diffraction limited,modulation transfer function (MTF) reaches 0.38 at the Nyquist frequency of 50 lp/mm with 6% central obscure,and optical system distortion is less than 0.5%. So this kind of optical system can meet the demand for the use of high resolution space cameras. At the same time,the large F number,long focal length design principle are approved.

The time delay characteristics of integrated waveguide microring resonator with tunable coupler constructed by the Mach-Zehnder interferometer (MZI) is analyzed,and the time delay response function is deduced. The results show that the variation of the phase difference between the two arms of MZI tunes the equivalent coupling coefficient of the microring resonator,and it also changes the additional phase of the tunable coupler,which makes the resonant frequency shift of the microring resonator. The influence of the discrepancy of coupling coefficients of the 3 dB couplers in MZI on the tuning range of the equivalent coupling coefficient and the resonant frequency shift of the microring resonator is also presented. By amending the phase of ring waveguide,the target delay time of 0.6 ns,bandwith of 2 GHz,and delay time ripple metric less than 1×10-3 ns2 are obtained with cascaded four microring resonators.

A novel fiber Bragg grating (FBG) tilt sensor with simple and stable structure is proposed to detect the magnitude as well as the direction of a two-dimensional inclination by using four FBGs with different reflective wavelengths. High angle sensitivity and measurement resolution are achieved and the temperature effect is eliminated completely without additional temperature compensation schemes. Preliminary results verified the feasibility of the proposed idea and showed that the tilt angle accuracy and resolution of the FBG tilt sensor are very good. Resolution of about 0.3° has been achieved. It is important to emphasize that the performance of the FBG tilt sensor can be further improved. The accuracy and resolution of the sensor can be easily increased by either using a heavier weight or decreasing the angle between the hanging fibers.

The TiO2 powders codoped by mole fraction x(Er3+)=0.1% Er3+ and x(Li+)=0-2% Li+ are prepared by the sol-gel method. The TiO2 phase transition from anatase to rutile is accelerated by Li+ codoping at the sintering temperature of 800 ℃,while only rutile phase existes at 900 ℃ and 1000 ℃. The green and red upconversion emissions centering at about 526,550 and 663 nm are detected by using a 976 nm semiconductor laser diode excitation. The two-photon absorption upconversion process is responsible for the green and red upconversion emissions. With the increase of the Li+ codoping concentration,the upconversion emissions intensities of Er3+-Li+:TiO2 sintered at 800 ℃ decreases,and that increases firstly and then decreases at 900 ℃,while the emission intensity increases significantly at 1000 ℃. The changes of crystal-field symmetry of Er3+ caused by Li+ codoping at different sintering temperature result in the variation of upconversion emission intensities of Er3+-Li+:TiO2. It is found that Li+ codoping can efficiently enhance the upconversion emission intensities of Er3+:TiO2.

By adjusting the proportion of the host composition,the crystal structure,the luminescent properties and the long afterglow characteristics of phosphor SrAl2xO3x+1:Eu2+,Dy3+(x=1-2) are studied. Selecting strontium nitrate and aluminum nitrate as raw materials of host,ammonium borate and aluminum fluoride as fluxes,and using cationic oxalic acid co-precipitation,wet mixing,stepwise synthesis etc.,a series of long-afterglow phosphors with high brightness,long duration and good particle-size distribution are prepared. Based on the analyses on the X-ray diffraction (XRD) pattern,the scanning electron microscope (SEM) micrographs,the excitation and emission spectra and the afterglow decay curve of the sample,it is found that SrAl2xO3x+1:Eu2+,Dy3+ has a good crystal structure,the emission peak shows blueshift from 520 nm to 470 nm and the afterglow time for attenuation to recognizable luminous intensity (0.32 mcd/m2) is extended from 30 h to above 60 h when x increases. The study found that the main reason of different afterglow is that there are two types of Eu2+ luminous centers (blue and green-emitting) with different concentration and different fluorescence-decay time in the host. The fluorescence lifetime of blue-emitting center is apparently longer than that of the green emitting center.

The glasses with the composition of y(LiPO3):y[Al(PO3)]:y(AgNO3)=x:(100-x):4(x=90,80,70,60,50 in molar ratio) were prepared with conventional melt-quenching method. Effects of Al(PO3)3 contents on the physico-chemical characteristics and spectroscopic properties were studied. It is found that the refractive index,density,glass transition temperature (Tg) and onset crystallization temperature (Tx) increased with the increase of Al (PO3)3 content. The increase of aluminum content strengthens the glass network,thus improving the physical and chemical properties of the glass. The glass with the composition y(LiPO3):y[Al(PO3)3]:y(AgNO3)=70:30:4 possesses good UV transmittance,higher irradiation induced absorption,intense fluorescence intensity and lower predose. Evaluated from the physical,chemical and spectroscopic properties,y(LiPO3):y[Al(PO3)3]:y(AgNO3)=70:30:4 glass is a promising candidate material for radio-photolumi nescence glass.

A new Eu2+/Sm3+ co-doped silicate glass was prepared,and its thermal stability and optical properties were studied. The intense blue (475 nm),yellow (562 nm),orange (599 nm) and red (644 and 706 nm) emissions were simultaneously observed at the room temperature under the excitation at 360 nm. The blue (475 nm) luminescence is due to the 4f65d1→4f7 transition of Eu2+,the yellow (562 nm) luminescence is due to the 4G5/2→6H5/2 transition of Sm3+,the orange (599 nm) luminescence is due to the 4G5/2→6H7/2 transition of Sm3+ and the red (644 and 706 nm) luminescence is due to the 4G5/2→6H9/2 and 4G5/2→6H11/2 transitions of Sm3+,respectively. With the increase of the concentration of Sm3+ ions,the hue of Eu2+/Sm3+ co-doped silicate glass varies gradually from greenish blue eventually to white. When the doped molar fraction of Eu2+ and Sm3+ ions are 0.05% and 1.0% respectively,the chromaticity coordinate of the glass is measured to be (0.312,0.307),which is close to the standard pure white (0.333,0.333). The results indicate that Eu2+/Sm3+ co-doped silicate glass is potential materials for white light-emitting diodes (WLED).

In order to obtain upconversion nanofibers materials of a new morphology,PVP/[Y(NO3)3+Al(NO3)3+Er(NO3)3+Yb(NO3)3] composite fibers were prepared by electrospinning,and Er3+,Yb3+:Y3Al5O12(Er3+,Yb3+:YAG for short) upconversion nanofibers were fabricated by calcination of the as-prepared composite nanofibers. Thermogravimetry and differential thermal analysis (TG-DTA) revealed that the water,organic compounds and nitrate salts in the composite nanofibers were decomposed and volatilized totally,and the weight of the sample kept constant when temperature was above 550 ℃,and the total weight loss percentage was 90.2 %. X-ray diffraction (XRD) results showed that the composite nanofibers were amorphous in structure,and pure phase Er3+,Yb3+:YAG nanofibers were obtained by calcination of the relevant composite fibers at 900 ℃ for 10 h. Fourier transform infrared spectrometer (FTIR) analysis manifested that crystalline Er3+,Yb3+:YAG upconversion nanofibers was formed at 900 ℃. Scanning electron microscope (SEM) analysis indicated that the diameter of Er3+,Yb3+:YAG upconversion nanofibers was about 75 nm,and the length was greater than 100 μm. Upconversion emission spectra showed under the excitation of a 980 nm continuous-wave diode laser,Er3+,Yb3+:YAG nanofibres emitted green and red upconversion emissions centered at 522,554 and 650 nm,respectively. The green(522 nm and 554 nm) and red(650 nm) emissions were attributed to the transitions of 2H11/2/4S3/2→4Il5/2 and 4F9/2→4Il5/2 energy levels of Er3+ ions. The formation mechanism of the Er3+,Yb3+:YAG nanofibers were preliminarily discussed. This method could be applied to prepare the other rare earths garnet-typed compound nanofibers.

Silicon nanocrystals (nc-Si) quantum dots is one of the most promising and important fields in the research and application of Si luminescence nowadays. The nc-Si embedded in SiO2 thin film is grown on Si substrate by using thermal evaporation method. Strong photoluminescence of nc-Si is observed. The films are investigated by spectroscopic ellipsometer in the visible region at room temperature. Employing the effective-medium approximation (EMA) model combined with the Lorentz oscillator model in the ellipsometric parameters fitting,the optical constants of nc-Si with the sizes of 3 nm and 5 nm are obtained,respectively,in the spectral region from 300 nm to 830 nm. The data obtained will be helpful for the design and manufacture of Si-based micro-nanophotonic devices.

Although organic light-emitting device (OLED) has been commercialized since 1997,blue light-emitting material is still a challenge for full color display. It is crucial to develop blue emitting material with high efficiency and color purity. The thermal stability and its color purity of blue electrophosphorescent materials are still far from commercialization,but a lot of achievements on excellent blue electrofluorescent materials have been made. Anthracene derivatives and spirobifluroene compounds show high performance in thermal stability and color purity,while nitrogen-containing compounds are competitive in efficiency because of their special electronic structure. Based on its structure,the blue electrofluorescent materials can be classified into aromatic hydrocarbons,nitrogen-containing compounds,and other organic compounds containing other hetero-atoms. The developments of blue electrofluorescent materials are reviewed at present,and the prospect on blue electrofluorescent materials is also discussed.

Ultra-short linear cavity is the simplest configuration to achieve stable single-frequency laser output. In order to increase the rare-earth doping concentration we choose phosphate glass as the laser gain medium. The spectroscopic properties of heavily Yb3+-doped phosphate glasses(P2O5-B2O3-K2O-BaO-Al2O3-Nb2O5-Sb2O3) have been investigated for developing 1064 nm single-frequency fiber laser. The experimental results show that the molar fraction solubility of Yb2O3 in this phosphate glass system is up to 6% (mass fraction 15.5%). Based on the reaction atmosphere process,the OH- groups can be removed effectively and the fluorescence lifetime of the 2F5/2 state of Yb3+ ion in phosphate glass reaches 1.84 ms. The Yb3+-doped phosphate glass fiber has been drawn by the rod-in-tube technique. A continuous-wave single frequency laser with 51.6 mW laser output at 1063.5 nm is achieved in a 1.4 cm phosphate glass fiber through a narrow bandwidth Bragg grating.

Lutetium oxide nanocrystals codoped with Tm3+ and Yb3+ were synthesized by the co-precipitation method. The obtained samples were characterized by X-ray diffraction (XRD),field emission scanning electron microscope (FE-SEM) and upconversion spectra measurements. Effect of the Tm3+ molar concentration and calcination temperature on the structure and upconversion luminescent properties of the nanocrystals have been investigated. The XRD results show that all the samples can be readily indexed to pure cubic phase of Lu2O3 and indicates good crystallinity. The experimental results show that concentration quenching occurs when the doping mole fraction of Tm3+ is above 0.2%. Blue,red and near infrared emissions from the prepared samples have been observed at 980 nm laser excitation. With the increase of the calcination temperature,the grain sizes and upconversion emission intensity of nanocrystals increase. Power-dependent investigation reveals that the blue(490 nm) and red(653 nm) upconversion fluorescence is three-photon upconversion process. The near infrared(811 nm) upconversion fluorescence is a two-photon upconversion process.

Glass ceramics based on mass fraction of 0.6% Ho3+-doped 65GeS2-25Ga2S3-10CsI (in molar fraction) chalcohalide glass are prepared by various heat treatment technique. The densities,micro-hardness,infrared transmission and mid-infrared emission spectra of the samples are measured,and their differences between host glass and glass ceramic are investigated. The results show that the density and micro-hardness markedly increased after heat treatment and further increase with treating duration. X-ray diffraction (XRD) and scanning electron microscope (SEM) measurements indicate that GeS2 phase with grain size of 80 nm are precipitated after treating the host glass at 440 ℃ for 12 h,and the mid-infrared emissions of Ho3+ ions of this glass ceramic sample at 2.0 μm and 2.9 μm are enhanced significantly.

The Mn,Cr-doped and Mn,Cr-co-doped MgAl2O4 powders were synthesized via a gel-solid reaction method at 1400 ℃. A green emission (520 nm) was obtained when Mn-doped sample was excitated at 450 nm. Whilst a red emission (689 nm) was obtained when Cr-doped sample was excitated both at 397 nm and 545 nm as well as a blue emission (450 nm) when excitated at 397 nm. The co-doped Mg1-xAl2(1-y)O4:xMn2+,yCr3+ powders emit green light (515 nm) and red light (677 nm,694 nm ) under pumping at 450 nm. It is found that the energy transfer exists in MgAl2O4 between Mn2+ and Cr3+ in the form of mutual energy accepting and donoring,and the Mn2+ ions have a strong sensitization on Cr3+. Therefore,MgAl2O4:Mn2+,Cr3+ could be used as a phosphor for white LED with blue LED chip. It is proven that the energy transfer in terms of Mn2+ to Cr3+ is by means of radiation and reabsorption.

Tm3+/Yb3+,Ho3+/Yb3+ and Tm3+/Ho3+/Yb3+ doped bismuth tellurite glasses exhibiting multicolor upconversion fluorescences are fabricated,and the upconversion fluorescence spectrum is investigated under 974 nm laser excitation. Because the blue upconversion luminescence of Tm3+ is a three-photon process,the increasing rate of blue emission is higher than the green and red ones in the Tm3+/Ho3+/Yb3+ triply doped bismuth tellurite glasses. The color coordinates of the sample are calculated,and the dependence of color coordinates on the pumping power is described. With the pumping power increasing,the color coordinate marks move along the down-left direction in 1931-CIE chromaticity diagram. The results indicate that the relative ratios of green,red and blue emission intensities can be tuned by adjusting pumping power,and white lighting could be realized in Tm3+/Ho3+/Yb3+ triply doped bismuth tellurite glasses. It confirms that Tm3+/Ho3+/Yb3+ doped bismuth tellurite glasses are effective upconversion materials and will be potentially employed in the application field of multicolor display and white light illumination.

Target detection is one of the most important aspects in remote sensing theory and application. Hyperspectral image can provide radiation,geometrical and spectral information of targets simultaneously,making target detection much better than other methods. A target detection algorithm based on variance minimum (BVM) which makes use of highlighting information of detection results is presented. And two experiments on different spatial resolution and spectral resolution are conducted to compare BVM method and constrained energy minimization (CEM). Results show the more robust performance of BVM method.

The imaging process of a strip-map mode synthetic aperture ladar (SAL) ultilzing quasi-monochromatic light illumination is investigated based on optics diffraction theory. The theoretical expressions of the matched filters and the corresponding azimuth resolutions for synthetic aperture imaging under several conditions are given. Results show that the matched filter in a strip-map mode SAL is not only expressed in transmitting wavelength,target distance and SAL azimuth coordinate,but also coupled with the transmitting beam and the configuration of the receiving optics. As a result,for a laboratory-scale SAL demonstration system utilizing Gaussian beam as the detecting light,the expressions of the matched filter for azimuth synthetic aperture imaging vary slightly as the target plane is positioned at the beam waist,inside Rayleigh range or outside multiple Rayleigh range of the transmitting beam. It is suggested that the target should be placed outside the multiple Rayleigh range in order to obtain the high azimuth resolution.

The phase transmission process of received radiation signals is analyzed. And the passive synthetic aperture imaging is compared with traditional optical synthetic aperture imaging,and the spatial resolution factor is defined based on array scaling factor. By the study of spatial resolutions of the antenna array and the fiber array,the influence of spatial resolution factor and array scaling factor on the spatial resolution in whole imaging system are discussed,and the spatial resolution equation is deduced for passive synthetic aperture imaging systems. Then the influences of array scaling factor and received radiation direction on the system′ spatial resolution are investigated respectively by simulations and calculations. In the end,the significances of the research results about the spatial resolution are emphasized in designing passive synthetic aperture photonic imaging systems.

The mixing process of three narrow line-width laser beams with different wavelengths in the sample is analyzed with semi-classical theory and a set of coupling-wave equations for describing the generation process of coherent anti-Stokes Raman Scattering (CARS) signals is derived. Based on the derived CARS coupling-wave equations and the principle of the time-resolved method,a set of coupling-wave equations for describing the time-resolved CARS (T-CARS) method is obtained. The variation of CARS signals and non-resonant background noise with incident laser beams in the T-CARS method and the decaying process of molecular vibrations have been investigated by numerical simulation. The decaying time of molecular vibrations can be used to distinguish different molecules with similar components and structure,and monitor the change of microenvironment. Theoretical study of T-CARS method using narrow line-width laser source shows that whole Raman spectra of biomolecules can be obtained by using wide-spectrum laser source.

The spectral properties of odd-parity highly excited states of europium Eu atom have been investigated with the technique of two-color three-photon resonant ionization spectroscopy in the energy region of 42896-44854 cm-1. The spectral information of 93 highly excited states of europium atom has been reported in this energy region. On the one hand,three different excitation pathways are used,not only the energy values of these states have been measured,but also the relative strengths of their photoionization signals are given. On the other hand,according to the selection rules of the electric dipole transition,the total angular momentum quantum numbers J of these states have been uniquely determined by analyzing and comparing the spectral data obtained in the experiment. Comparisons with the published literatures,25 new odd-parity highly excited states of europium atom have been discovered,which lie in the region of the present investigation,except for confirming some of the states reported in the literatures. In addition,the spectral information of several highly excited states from the literatures has been amended,and the J values of these states also have been assigned uniquely.

Defects were shown on the multiple cavity induced transmission filters (ITF),which greatly affected the sample′s quality and environmental stability. Four-cavity ITF were prepared by evaporation method on the float glass at room temperature. Defects topographies were observed by optical microscope,and the defects were divided into different kinds of dig defects and scratch defects. Depth information and elementary composition of defects were obtained by optical profiler and EDS energy spectra analysis. The results showed the defects were mainly caused by unclean substrate,sputtering and other composite reasons like stress and sub-surface defects. In order to suppress the defect with numbers,width and depth,acid cleaning techniques were tested and confirmed effective. Good results achieved with improved techniques were made according to genetic analysis of defects.

Based on the birefringent characteristic of thin film fabricated by glancing angle deposition(GLAD),a birefringent non-polarizing thin film at wavelength 632 nm only using titanium oxide is designed and deposited. At the beginning,two titanium oxide monolayers were deposited with the deposition angle 60° and 70° respectively. The effective refractive index of the monolayer for s- and p-polarization,nPH,nSH and nPL,nSL ,were obtained. a higher s transmittance than p polarization at normal incidence is got by arranging the index correctly,since the increase of the incidence would bring an opposite effect,we could get a non-polarizing effect at a very angle can be got. Based on the analysis above,a non-polarizing thin film was designed and prepared. The s- and p-polarization transmission spectra of non-polarizing film were measured with photometer at normal and tilted incidence. At the incidence angle of 60°,the reflection band width of s- and p-polarizations were less different and the non-polarizing effect was achieved partially. The obliquely incident non-polarizing thin film can be designed based on the thin film material′s birefringence.

In order to design and fabricate quarter wavelength high performance polarizing beam splitter (PBS),based on equivalent layers concept and stopband theoretics,two types quarter wavelength periodic multilayer PBS are proposed. The TFCalc software is used for the calculations and analysis. The polarizing beam splitters are fabricated by electron gun vapour deposition in spectrum range of 580-780 nm. The transmissivity characteristic of PBS is investigated by spectrometer,and the extinction ratio characteristic is measured by the constructed setup in the experiment. The experimental results indicated that the transmissivity reachs 90% or more,and the extinction ratio is better than 3×10-3. The experimental results consistent with theoretical performance of the layer design.

Kretschmann surface plasmon resonance (SPR) films structure is one of the most important parts of probe induced surface plasmon resonance coupling nanolithography (PSPRN). The film characteristic matrix method is used to calculate the transmission coefficient and the reflectivity of the layers for optimal design of single-,two- or three-films structure of PSPRN. Optimal results for the selected film materials are obtained at the wavelength of 514.5 nm. For single film structure,the optimal thickness of Ag film is 46 nm. The optimal thickness of the Ag film is 24 nm and the AgOx film is 95 nm for two-film structure. For three-film structure,the optimal result is that the thickness of Ag film is 44 nm,SiO2 film is 180 nm,and AgOx film is 10 nm. Furthermore,it is presented that the material with small refractive index and low absorption coefficient is more effective as the recording layer.

The IPT color space has been used in the study of gamut mapping and image color appearance model. The uniformity of IPT was investigated using Munsell system and Ebner and Fairchild′s constant hue data sets,and compared with calculated ones of CIELAB color space. Tristimulus value X,Y and Z of Munsell data set with an illuminant of D65 were used as input of IPT and CIELAB to compute lightness,chroma,and hue. The calculated results showed that:IPT and CIELAB models have similar performance in lightness uniformity;CIELAB has better performance than IPT in chroma uniformity;on hue uniformity,the IPT is only better in blue area and has better linear relation in every hue angle than CIELAB with Munsell data set,however,the IPT is better than CIELAB with Ebner and Fairchild′s constant hue data sets.