A prototype Raman lidar was designed for monitoring tropospheric CO2 profile and other scientific investigations. The third harmonic of Nd:YAG laser (354.7-nm wavelength) was used as stimulated light source to provide nighttime measurements. Filter with high rejection ratio performance was used to extract CO2 Raman signals from Rayleigh-Mie scattering signals effectively. To improve the real time monitoring function, a two-channel signal collection system was designed to collect CO2 and N2 Raman scattering signals simultaneously. The N2 Raman scattering signals were used to retrieve aerosol extinction coefficient. Typical features of CO2 concentration profile and aerosol extinction coefficient in Hefei were presented. The mixing ratio of atmospheric CO2 in Hefei can reach about 360-400 ppmv.

Considering the perturbation, the results of theoretical calculation of five Rydberg series energy levels 6s2ns2S1/2(n=7-20),6s2nd2D3/2(n6-20),6s2nd2D5/2(n=6-20),6s2np2P^(0)_(1/2)(n=7-20), and 6s2np2P^(0)_(3/2)(n7-20) for Tl I are presented using the weakest bound electron potential model (WBEPM) theory. Furthermore, the radiative lifetimes of this five series are also calculated. The calculated values of energy levels and lifetimes are in good agreement with the experimental results.

Based on the point spread function of holographic system, the lateral resolution of digital holographic imaging system without any pre-magnification is studied. The expression of resolution limitation of holographic imaging system is thus presented. We investigate the possibilities to improve the lateral resolution. The simple experimental setup with an off-axis arrangement is built. By using a U.S. Air Force (USAF) test target as microscopic object, the recorded holograms are reconstructed digitally based on the principle of Fresnel diffraction. The lateral resolution of 2.76 \mum without any pre-magnification is demonstrated experimentally, which matches the theoretical prediction well.

The kernel based tracking has two disadvantages: the tracking window size cannot be adjusted efficiently, and the kernel based color distribution may not have enough ability to discriminate object from clutter background. For boosting up the feature's discriminating ability, both scale invariant features and kernel based color distribution features are used as descriptors of tracked object. The proposed algorithm can keep tracking object of varying scales even when the surrounding background is similar to the object's appearance.

Conventional Gabor representation and its extracted features often yield a fairly poor performance in extracting the invariance features of objects. To address this issue, a global Gabor representation method for raised characters pressed on label is proposed in this paper, where the representation only requires few summations on the conventional Gabor filter responses. Features are then extracted from these new representations to construct the invariant features. Experimental results clearly show that the obtained global Gabor features provide good performance in rotation, translation, and scale invariance. Also, they are insensitive to illumination conditions and noise changes. It is proved that Gabor filters can be reliably used in low-level feature extraction in image processing and the global Gabor features can be used to construct robust invariant recognition system.

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance (SPR) sensing system with ultra-high resolution performance is presented. The system exhibits a root-mean-square phase fluctuation of +-0.0028 angle over a period of 45 min, i.e. a resolution of +-5.2*10^(-9) refractive index units. The enhanced performance has been achieved through the incorporation of three design elements: a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected, a differential measurement scheme to eliminate spurious signals not related to the sensor response, and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulator. Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.

The numerical moire method with sensitivity as high as 0.03 nm has been presented. A quantitative displacement and strain analysis program has been proposed by using this method. It is applied to an edge dislocation and a stacking fault in aluminum. The measured strain of edge dislocation is compared with theoretical prediction given by Peierls-Nabarro dislocation model. The displacement of stacking fault is also obtained.

In order to improve the optical properties of the III-V laser diodes (LDs) by means of H2S plasma passivation technology, H2S plasma passivation treatment is performed on the GaAs(110) surface. The optimum passivation conditions obtained are 60-W radio frequency (RF) power and 20-min duration. So the laser cavity surfaces are treated under the optimum passivation conditions. Consequently, compared with unpassivated lasers with only AR/HR-coatings, the catastrophic optical damage (COD) threshold value of the passivated lasers by H2S plasma treatment is increased by 33%, which is almost the same as that of (NH4)2Sx treatment. And the life-test experiment has demonstrated that this passivation method is more stable than (NH4)2Sx solution wet-passivated treatment.

The characteristics of coherent coupling in Mach-Zehnder erbium-doped fiber laser cavity are experimentally studied. By virtue of a seemly controlling of length difference between two interferometric arms, the obtained comb-like spectrum of interferometer resonator with a period of 0.06 nm commendably agrees with the theory of self-organization coherence. The coherent output exits from the output mirror of a fiber Bragg grating with 4.5% reflectivity. A high coherent combining efficiency of 94% is obtained. Investigation on characteristics of the leak power opens out self-organization mechanism in Mach-Zehnder composite cavity.

The carrier-envelope phase of the ultrashort pulsed Laguerre-Gaussian beam is studied. The order of Laguerre function affects seriously the variations of the carrier-envelope phase with the propagation distance increasing. The beam waist also affects the carrier-envelope phase in a few Rayleigh distances. The variation of the carrier-envelope phase is larger on the axis than on the beam periphery in propagation.

The generation of ultraviolet (UV) light at 335.5 nm based on frequency quadrupling of a diode-end-pumped Q-switched Nd:YVO4 laser at 1342 nm was demonstrated. KTP crystal was used for generation of wavelength of 671 nm by intracavity doubling and LBO (BBO) crystal was exploited for the subsequent external fourth harmonic generation (FHG). With 6.3-W absorbed pump power and 10-kHz frequency repetition rate, the UV output power of 35 and 63 mW were obtained by using LBO and BBO as frequency quadrupling nonlinear crystals, respectively. The experimental results show that the conversion efficiency (red-UV) of 6.4% for BBO crystal is higher than that of 3.5% for LBO crystal, but the UV beam quality obtained by LBO crystal is better than by BBO crystal.

An optical alignment-free and highly accurate method is employed to measure the magnetic field-dependent refractive index of magnetic fluid (MF) in bulk. The measured refractive index decreases significantly with the increasing magnetic strength and then tends to saturate in the high intensity range. By applying a tunable magnetic field ranging between 0 and 1661 Oe, the maximum shift of the refractive index of MF in bulk is found to be 0.0231.

Band structures of one-dimensional (1D) photonic crystals (PCs) containing dispersive left-handed metamaterials are studied theoretically. The results show that the structure possesses a type of photonic band gap originating from total internal reflection (TIR). In contrast to photonic band gaps corresponding to zero average refractive index and zero phase, the TIR gap exhibits sharp angular effect and has no polarization effect. It should also be noted that band structures of transverse electric (TE) and transverse magnetic (TM) mode waves are exactly the same in the PCs we studied.

Transmission studies for one-dimensional photonic crystals (1DPCs) containing single-negative (SNG) materials inserted with multiple defects are presented. The numbers and positions of the defect modes inside zero-phase (zero-\fai eff) gap are found to be well characterized by effective medium theory.

A low-threshold middle-infrared (mid-IR) MgO:PPLN optical parametric generation (OPG) pumped by a laser diode (LD) end-pumped Z-type Nd:YLF laser at 1047 nm is realized with high reflectivity(HR) mirror for signal. At repetition rate of 10 kHz, the OPG threshold of 50 'mu'J has been achieved with HR mirror for signal. Compared with the threshold without mirror, the threshold decreases by 17%. Using HR mirror for pump at output side of crystal, the threshold of 40 'mu'J is achieved. The 2.7-4.1 'mu'm continuous tunable output is produced with seven grating periods from 28.5 to 31.5 'mu'm and temperatures from 30 to 200 . When the incident average pump power is 3 W, the OPG idler output power is 0.46 W at 3.26 'mu'm, which corresponds to optical-to-optical conversion efficiency up to 15.3%.

We derive the threshold pump intensity for a singly resonant intracavity optical parametric oscillator (IOPO) based on a temporal coupled field model. Particular attention is paid to the dependence of the intracavity singly resonant OPO (SRO) threshold intensity on the signal wave output coupling. Meanwhile, a Nd:YAG laser pumped KTiOPO4 (KTP) IOPO for eye-safe laser output is studied experimentally. The experiment is performed with four signal wave output reflectivities of 60%, 70%, 80%, and 90%, respectively. The measured values are in good agreement with the theoretical results. With an output coupler reflectivity of 80%, a peak power of 70 kW at 1572 nm has been obtained at a repetition rate of 3.5 kHz. The pulse width is 4.9 ns. Such investigation is helpful to identifying suitable operational regime of low pump intensity.

The (2+1)-dimensional nonlinear Schrodinger (NLS) equation with spatially inhomogeneous nonlinearities is investigated, which describes propagation of light in (2+1)-dimensional nonlinear optical media with inhomogeneous nonlinearities. New types of optical modes and nonlinear effects in optical media are presented numerically. The results reveal that the regular split of beam can be obtained in (2+1)-dimensional nonlinear optical media with inhomogeneous nonlinearities, by adjusting the guiding parameter. Furthermore, the stability of beam regular split is discussed numerically, and the results reveal that the beam regular split is stable to the finite initial perturbations.

A model for measuring aerosol mass concentration by an optical particle counter is presented using the conception of the average mass. In this model, to understand the meaning of the pulse height distribution of particles which is used to inverse mass concentration, the relationship among intensity distribution in the optical sensing volume, particle shape, and the pulse height distribution is discussed. To solve the instability of the equivalent factor, a novel two-step calibration method is proposed. The experimental results demonstrate that mass concentrations calculated by the model are in good agreement with those measured by a norm-referenced instrument. For samples of soot and air, the slopes of fitting lines of data points are 0.9582 and 0.9220, and the correlation coefficients are 0.9991 and 0.9965, respectively.

The optical emission spectra (atomic hydrogen (H'alpha', H'beta', H'gamma', atomic carbon C (2p3s->2p2: 'lambda'=165.7 nm) and radical CH (A2'Delta'->X2'pi':'lambda'=420-440 nm)) in the gas phase process of the diamond film growth from a gas mixture of CH[EQUATION] and H[EQUATION] by the technology of electron-assisted chemical vapor deposition (EACVD) have been investigated by using Monte Carlo simulation. The results show that the growth rate may be enhanced by the substrate bias due to the increase of atomic hydrogen concentration and the mean temperature of electrons. And a method of determining the mean temperature of electrons in the plasma in-situ is given. The strong dependence on substrate temperature of the quality of diamond film mainly attributes to the change of gas phase process near the substrate surface.

The impurities in two kinds of HfO2 materials and in their corresponding single layer thin films were determined through glow discharge mass spectrum technology and secondary ion mass spectrometry (SIMS) equipment respectively. It was found that ZrO2 was the main impurity in the two kinds of HfO2 either in the original HfO2 materials or in the electron beam deposited films. In addition, the difference of Zr content in the two kinds of HfO2 single layer films was much larger than that of the other impurities such as Ti and Fe, which showed that it was just ZrO2 that made the difference between the optical performance of the film products including the two kinds of HfO2. With these two kinds of HfO2 and the same kind of SiO2, we deposited HfO2/SiO2 multilayer reflective coatings at the wavelength of 266 nm. Experimental results showed that the reflectances of these two mirrors were about 99.85% and 99.15% respectively, which agreed well with the designed results what were based on the optical constants obtained from the corresponding single layer thin films.

HfO2/SiO2 multilayer films were deposited on BK7 glass substrates by electron beam evaporation method. The effects of annealing at the temperature between 200 and 400 centigrade on residual stresses have been studied. It is found that the residual stress of as-deposited HfO2/SiO2 multilayers is compressive. It becomes tensile after annealing at 200 centigrade, and then the value of tensile stress increases as annealing temperature increases. And cracks appear in the film because tensile stress is too large when the sample is annealed at 400 centigrade. At the same time, the crystallite size increases and interplanar distance decreases with the increase of annealing temperature. The variation of residual stresses is corresponding with the evolution of structures.

Ta2O5 films are prepared on BK7 substrates with conventional electron beam evaporation deposition. The effects of SiO2 protective layers and annealing on the laser-induced damage threshold (LIDT) of the films are investigated. The results show that SiO2 protective layers exert little influence on the electric field intensity (EFI) distribution, microstructure and microdefect density but increase the absorption slightly. Annealing is effective on decreasing the microdefect density and the absorption of the films. Both SiO2 protective layers and annealing are beneficial to the damage resistance of the films and the latter is more effective to improve the LIDT. Moreover, the maximal LIDT of Ta2O5 films is achieved by the combination of SiO2 protective layers and annealing.

Scanner color management is one of the key techniques for color reproduction in information optics. A new scanner color management model is presented based on analyzing rendering principle of scanning objects. In this model, a standard color target is taken as experimental sample. Color blocks in color shade area are used to substitute complete color space to solve the difficulties in selecting experimental color blocks. Immune genetic algorithm is used to correct back-propagation neural network (BPNN) to speed up the convergence of the model. Experimental results show that the model can improve the accuracy of scanner color management.