The deformation process of material shocked by strong and short pulsed laser has high strain rate. Response bandwidths of many testing instruments are not wide enough to effectively measure the deformation process. The velocity interferometer system for any reflector (VISAR) commonly used to test dynamic deformation is complex and expensive. Especially it has the drawback of lacking stripes. A simple and novel optoelectronic measurement system is applied to measure the deformation. With the calibration of ratio of the output voltage and the deformation, the displacement and velocity of shock center can be worked out. The displacement and velocity law are similar with the simulation result reported. The average deformation velocity in shock period is calculated as 8.49×104 m/s. The analysis of the data, based on the fitting curve, shows that the deformation is superimposed the movement of damped oscillations and elastic deformation. Meanwhile, the vibration velocity and the plastic deformation of plate can be obtained through the fitting coefficient. These results provid a basis platform for the analysis and control laser shock deformation process.

A broad-band high-speed linearized swept laser source based on grating/polygon mirror tunable filter is reported. In order to facilitate the filtering system, the tunable filter consists of polygon scanner and grating in Littrow telescope-less configuration. Parallel implementation of two semiconductor optical amplifiers with different wavelength ranges is adopted in the laser resonator for broad-band light amplification. Center wavelength of the developed swept laser source is 1312 nm with a turning range of 170 nm and 3dB bandwidth of 116 nm. A repetition frequency up to 50 kHz with an average output power of 2 mW is realized while the polygon is scanned at a speed of 695 r/s. This high-speed broad-band linearized swept laser source is especially applicable to high resolution swept source based optical coherence tomography, of which the axial resolution can reach to 6.5 μm.

A fast photoacoustic imaging system based on multi-channel parallel acquisition, which is composed of ultrasonic detector, multi-channel parallel acquisition system, short-pulse laser, computer hardware platform and a pack of software for the control of the data acquisition and real-time imaging, is designed. Multi-channel parallel acquisition system consists of front-end analog amplifier, anti-aliasing filter, A/D converter, data storage, field programmable gate array (FPGA) control and universal serial bus (USB) transfer and it has 64-channel full parallel acquisition and digital processing. The results of imitative sample show that multiple locations of rotating scan imaging improve the signal to noise ratio (SNR) greatly. Consequently, it is characterized by fast imaging and is expected to be a noninvasive real-time tissue imaging system with high repetition frequency laser as excitation and provide a new method for clinical noninvasive detection.

It is known that artesunate (ART) induced apoptosis is due to the reactive oxygen species (ROS) generation which triggers many apoptosis. DCFH-DA and Rhodamine 123 were used to probe the level of ROS and mitochondrial membrane potential. Time-lapse confocal fluorescence microscopy was used to monitor the dynamics of ROS generation and the loss of mitochondrial membrane potential during ART-induced human lung adenocarcinoma cells (ASTC-a-1) apoptosis. The data show that the cell ability can be reduced by ART of 0~50 μg/mL. ART of 40 μg/mL which be used to generate significantly ROS can induce notablely loss of mitochondrial membrane potential. Results show that N-acetylcysteine (NAC), a scavenger of ROS, can significantly inhibits the ART-induced apoptosis and the loss of mitochondrial membrane potential and ART induces ROS-mediated apoptosis and loss of mitochondrial membrane potential.

According to the characteristic of lidar-return noise, an effective de-noising method of wavelet packet based on average threshold is presented and described to reduce the lidar-return noise. In the method, the thresholds of every node of the best wavelet packet basis are acquired and averaged, and then the average value is used as a global threshold to quantize the decomposition coefficient of every node. To verify the feasibility of the de-noising method, some numerical simulations are carried out to reduce the Gauss white noise of the simulated signal, and also, the Mie lidar returns contaminated by noise are de-noised by the method. Moreover, the comparisons among the wavelet packet transform based on average threshold, wavelet transform based on global threshold and the wavelet packet transform based on default threshold are performed. Experiment results show that the method of wavelet packet based on average threshold is capable of effectively reducing the lidar return noise and the de-noising effect is better than other two methods.

Analytic image technique and wavelet transform(WT) technique are applied to analysis of interferometry hologram with a linear carrier. In this method, Hilbert transform is firstly performed on the hologram to get the analytic signals. And then WT is calculated on the signal. Finally, the phase information of the hologram can be obtained from the WT coefficients at the wavelet ridge position. Because of the good spatial localization ability of the mother wavelet, the error caused by the boundary of the hologram is limited in local areas. Filtering process is avoided in this method, so it can resolve the frequency overlapping problem to a certain extent. Mathematical demonstration is given in detail. Computer simulation and experiments verify the validity of the proposed method.

Based on the support of new developments in optical imaging, noninvasive, in situ, dynamic, real-time clinical skin diagnosis is realized. A new branch of the medical imaging and skin imaging has been developed as a new technical discipline for the past decade. This review focuses on the current optical imaging techniques that have been used in clinical diagnosis, including dermoscopy, confocal imaging, multiphoton imaging, optical coherence tomography and photoacoustic imaging. These five optical clinical diagnosis methods can supply a doctor with detailed and precise information of the targeted suspicious skin area, which provide objective evaluation. These new developments in skin imaging, compensate to the advances of skin histopathology research, will promote the fast development of modern dermatology.

Based on the experiments of laser-arc double-sided welding (LADSW) for a 4-mm thick stainless steel, the effects of laser power and arc current on weld cross-section, joint parameters and melting efficiency are mainly discussed. The results show that the weld cross-section of LADSW takes on the combination of typical weld profiles of laser welding and arc welding at lower heat input, while the combination characteristics doesn′t exist at higher heat input. The weld width at laser side increases with the increasing of laser power, whereas the weld width at arc side decreases at some extent. The increase of arc current can contribute to the increase of weld with at the arc side, but it doesn′t have much effect on the weld width at the laser side. The minimal weld width increases with the increase of both the laser power and arc current. The weld depth from minimal weld width to the laser side increases with the increase of the laser power, while decreases with the increase of the arc current. In the lack of penetration joint, the effect of the laser power on melting efficiency of arc welding is envident, while the effect of arc current on melting efficiency of the laser welding is little. In the full penetration joint, the melting efficiency of LADSW increases with the increase of both the laser power and arc current.

Compared with the traditionally manufacture of single mesa diode wafer which has some disadvantages such as low speed and high chipping rate of blade-sawing, laser scribing is of high yield rate because of non-contact processing. According to the properties of crystal silicon (Si), the direction of the scribing and its mechanism of Si processed by infrared (IR) laser are discussed. On the base of approximate analytical solution derived from one-dimensional heat conduction equation, the ablation depth influenced by laser power and scanning speed is calculated. 7.62 cm wafer scribed under the condition of 1064 nm pulsed fiber laser shows that chipping rate is less than 1% and eligible electrical properties attain 100%. Research shows that ablation depth can influence the chipping rate and defocusing amount can influence the electrical properties of the chip. High yield rate can be achieved by controlling the ablation depth and defocusing amount during the scribing.

Combination of back propagation(BP)neural network and particle swarm optimization (PSO) algorithms is used to optimize process variables during the laser cladding. BP neural network model is developed to express the relationship between the clad process variables and the clad parameters (the width, height of clad bead), and the samples obtained in experiments are used to train network model to form the perfect map relation between input and output. Then, PSO algorithm is used to grabble the suitable values of the process variables. The experimental clad parameters with the process variable values calculated by this optimization method are coincident well with the expected ones. It is verified experimentally that combination of BP neural network and PSO algorithms can help to obtain the expected laser clad quality.

Double-pulse laser controlling method used for film cooling holes processing of aircraft engine turbine blade is studied. Double-pulse laser experimental results of producing approximately 100 ns temporal delay between the pulses with polarization beam combining by two sets of flash-lamp pumped electrooptical Q-switched laser are reported. The interval of co-aligned double-pulse laser can be turned freely from 0 to several hundred nanoseconds. The maximal timing jitter of double-pulse laser is less than 5 ns. The repetition rate of double-pulse laser is 40 Hz, and output energy per double-pulse laser is more than 400 mJ.

The microstructure and mechanical properties of as-deposited and heat-treated laser solid forming (LSF) 17-4 PH (0Cr17Ni4Cu4Nb) percipitation-hardening stainless steel are investigated. The results of optic microscope (OM), scanning electron microscope (SEM) and X-ray diffraction (XRD) show that the microstructure of as-deposited LSF 17-4 PH steel consists of lath martensite and a small quatity of the second phase strengthening particles which distribute in and between the laths. According to the characteristics of alloy, the precipitating second phase strengthening particles should be M7C3 and NbC carbides, etc. The microstructure at the bottom of the deposited LSF 17-4 PH is mainly thin lath hardened martensite, however, there are thick lath martensite at the top of the deposited one. The microstructure of heat-treated LSF 17-4 PH is thin homogeneous lath martensite and there are more second phase strengthening particles percipitated in the subtrate as well. These second phase strengthening particles should be NbC and M7C3, M23C6 carbides. After heat-treatment,the strength and hardness of samples are slightly improved, while the plasticity is highly improved. In addition, the tensile strength and plastcity of the heat-treated samples are higher than forging bar standard, meanwhile, the yield strength is slightly lower than forging bar standard. The analysis on fractography shows that both the as-deposited and heat-treated LSF 17-4 PH steel exhibit toughness fracture and the second phase particles which consist of M7C3 carbides are the resource of microcavities and dimples.

Laser cladding monitoring is one of the cladding layer quality controlling methods. In this paper, one of the characteristic signal of plasma optical signal has been detected by phototube. TEM00 laser has been used in experiments with two scans like powder present cladding. Powder use Ni60 and the base material is 45# steel. The relationship between blue-violet light intensity and laser power scan velocity, as well as the relevance between quality of layer and intensity have been discussed. The results indicate that while laser power grows, the intensity increases just at a low rate, and the intensity decreases as scan velocity increases when the power is lower than a definite value. But when the power is greater than the values, the intensity will rise as velocity increases. The quality of layer is improved greatly when the intensity value rangs from 1.7 to 2.5 μW/cm2 with a slight fluctuation. Analysis shows that when the laser power threshold is breaken, the scanning speed increases and penetration shallows, and energy for material vaporizing increases, so intensity of blue-violet light grows.

Corner-pumped type is a new pumping type in the laser diode-pumped solid-state lasers, which has the advantages of high pump efficiency and favorable pump uniformity. Using the single corner pumped type, an efficient corner-pumped Nd:YAG/YAG composite slab continuous-wave 1.1 μm multi-wavelength laser is demonstrated in this paper. The compact plano-plane linear cavity configuration is adopted and the cavity length is only 22 mm. When the pump power is 50.3 W, the maximal output power is up to 10.9 W with an optical-to-optical conversion efficiency of 21.7% and a slope efficiency of 22%. The short-term instability of the output power is better than 0.6% when the pump power is 48 W.

Under the influence of thermal effect, how to optimize the conversion efficiency of laser diode (LD) end-pumped solid-state lasers is analyzed. Considering the effect of pump beam distribution, the laser medium and the resonator structure, a simulation algorithm is designed to calculate the thermal effects and laser conversion efficiency. The results show that thermally induced loss is relevant to pump radius, pump power, cavity length, oscillation light radius and crystal materials. It is independent of output mirror transmission and repetition rate. Considering the existence of thermally induced loss, there are optimum pump parameters and resonator parameters which make the conversion efficiency of NdYAG largest when pump power is fixed.

A novel drive power for narrow pulse laser diode, which is composed of driving circuit and temperature controlling circuit, has been designed. High speed metal-oxide-semiconductor field effect transistor (MOSFET) is applied in the driving circuit as the switch to provide the laser diode with smooth pulse of high repetition rate (0～50 kHz), fast rise time (2.2～4.9 ns), narrow pulse width (4.6～12.1 ns) and high peak pulse current (0～72.2 A). According to the requirements of variety of laser diodes, different repetition rates, rise time, pulse widths and peak pulse currents can be achieved by varying the voltage, resistor, capacitor in the circuit. A precise proportional-integral differential (PID) temperature controlling module is adopted in the circuit to ensure the stability of the output power and the central wavelength of the laser diode. The drive power can be not only used as the power supply for the traditional high speed, narrow pulse width laser diode, but also an ideal drive power for the high energy, narrow width pulse laser diode.

Using resonator inserted with acousto-optically modulator, the experiments of the compacted CO2 laser are performed with Q-switch. According to various factors that influence the output of laser, the theoretical calculation of its main parameters are conducted by Q-switched pulsed laser rate equations. Based on the results, the technical route and approach are presented for optimization design of this laser. The measured peak power of the acousto-optically Q-switched CO2 laser is more than 4000 W and pulse width is 180 ns which agrees well with the theoretical calculation. The range of repetition frequency can adjust from 1 Hz to 100 kHz. The theoretical analysis and experimental results show that the acoustic traveling time of ultrasonic field can not influence the pulse width of laser so that it doesn′t require inserting optical lens in the cavity to reduce the diameter of beam. The acoustic traveling time only extends the establishing time of laser pulse. The optimum working frequency of laser is about 1 kHz, which it matched with the radiation life time (1 ms) of CO2 molecular 0001 energy level. When the frequency is above 1 kHz, the pulse width of laser increases with the frequency. The full band of wavelength tuning between 9.2 μm and 10.8 μm is obtained by grating selection one by one which the measured spectrum lines are over 60 in the condition of Q-switch.

An efficient laser diode-pumped Yb:YGG laser is demonstrated by using a high quality Yb:YGG crystal grown by optical floating zone method, output power up to 1.95 W has been obtained under incident pump power of 6.7 W, corresponding to optical-to-optical efficiency of 29.1% and maximum slop efficiency of 60%. By using a semiconductor saturable mirror absorber (SESAM) to start and sustain the mode-locking, stable laser pulses of 2.1 ps has been obtained without dispersion compensation. The central wavelength is 1035 nm and the output power is 1 W, corresponding to optical-to-optical efficiency of 18.2%.

A wavelength-spacing tunable multi-wavelength fiber optical parametric oscillator (MW-FOPO) with a simple line cavity is proposed. A tunable laser provides the pump seed light. A pseudorandom modulation method is used to broaden the line-width of the pump seed light by employing a phase modulator, which can successfully suppress the stimulated Brillouin scattering (SBS) when the high power pump light is injected into the highly nonlinear optical fiber(HNLF). A high power erbium-doped fiber amplifier is used to achieve a high power pump source. Stable multi-wavelength lasing at room temperature is achieved due to the four wave maxing (FWM) effect and the broadband gain of the fiber optical parametric amplifier. The wavelength spacing of the MW-FOPO can be tuned by adjusting the wavelength of the pump light. Seventeen lasing lines with an extinction ratios larger than 10 dB which cover the wavelength region from 1505 to 1615 nm are achieved. Advantages of fiber optical parametric amplifiers to implement multi-wavelength fiber laser are demonstrated.

In order to improve focal spot concentration of 3ω laser, entire beam wavefront should be corrected. One of key technologies is to get entire beam wavefront aberration exactly. With Hartman wavefront sensor located at parameters diagnosis unit of main amplifier, wavefront of output main amplifier can be obtained. However, wavefront of target system can′t be measured directly. There are two methods to solve this problem including reverse calibration and direct measurement at target point. By comparing complexity and accuracy of the two methods, and combining far field measurement with and without correction, direct measurement at target point is a simple and correct method to get entire beam wavefront.

Reviewing the mechanism of fly′s eye lens homogenizing single beam source, the mechanism of fly′s eye lens homogenizing laser diode array is studied. Each single beam is split and superposed to break down the comparability between them, then the shaped beams are superposed to gain a uniform beam. Then a fly′s eye lens based beam shaping system for laser diode array, aiming to improve pumping intensity, is designed. The parameters of fly′s eye lens and integrating lens are given out. An experiment of the designed beam shaping system is done and the non-uniformity of result beam is measured, which confirms the analysis of fly′s eye lens homogenizing laser diode array.

Jet cooling technology is used in mirror cooling of high power lasers and water jet cooled mirror is designed based on this. 2D model is built and validated to calculate the convective heat transfer coefficient and pressure of liquid under certain parameters by fluid analysis module FLOTRAN in finite element analysis software ANSYS. 3D model is built to calculate corresponding temperature and deformation distribution of the mirror by the module of multi-physics in ANSYS, and the performance comparisons of different materials and different cooling methods are made. The results show that water jet cooled SiC mirror exhibits small mirror deformation, simple structure，good cooling uniformity and good pressure characteristic, which has great prospects in the application of high power lasers.

The major drawback of high power diode laser systems is their poor beam quality, which can be improved by beam shaping and beam combination. With the high wall-plug efficiency, high power laser diode developed rapidly. Base on bars rated to 60 W and 57% conversion efficiency, vertically stacked arrays (twenty bars) of such configuration are demonstrated with rated to 1183 W. The beam quality of high-power high brightness 880 nm laser diode source is improved with beam shaping. Beam parameter product of 79.3 mm·mrad×81.2 mm·mrad, electro-optical conversion efficiency of more than 45.8% and continuous output power of 1 kW are demonstrated. This laser can be directly applied to cladding, surface hardening and other fields.

Based on Hankel wave′s theory and geometric optical theory, the reconstruction of Bessel beam through an annular obstacle is studied. The results showed those non-diffracting beams generated by axicon are the superposition of two outgoing Hankel waves. Non-diffracting beams through annular obstacle are simulated with Zemax software. The cross sections of intensity distribution at different places on axis behind annular obstacle are also stimulated. The relationship between Bottle beam size and annular obstacle diameter is investigated. In the experiment, we use axicon to generate non-diffracting beam, and an annular obstacle is kept within the maximum collimating distance of the non-diffracting beam. Optical intensity distribution behind the annular obstacle is captured with CCD camera. The result agrees with the simulation. The theoretical analysis and experimental results both showed that reconstruction of Bessel beam with an annular obstacle can generate Bottlte beam with zero central optical intensity. There is a potential application in optical tweezers and optical micromanipulation.

Study of pulsed discharge characteristic of methyl iodide mixture gas is important for pulsed chemical oxygen iodine laser. The pulsed discharge profile of current and voltage, break voltage and peak voltage, deposited energy were studied and the trends were obtained. Break voltage and peak voltage goes linearly with product of pressure, interelectrode gap, initial voltage, and deposited energy goes linearly with product of pressure, discharge volume and initial energy deposited in the capacitance.

For the thermal blooming of the beam path indoor, solving the coupling equations of optical field and Fluent field completely is a meaningful and important subject. By means of segregated solving the coupling equations, a model for simulating the coupling equations is described based on the software of the Fluent. The procedure is compiled by the user defined equations, the parameters of the fluid are inputted and the distribution of the beam intensity is calculated. The absorbed laser energy is added to the energy equation of the fluency as the energy source. The fluency equations are solved by virtue of the Fluent software. As the straight tube with the round section, the results obtained by the theoretical methods are consistent with the outcomes achieved by the established model.

Optical properties, surface roughness and packing density of TiO2 thin films obliquely deposited on K9 glass by electron beam evaporation are investigated. The surface roughness of TiO2 thin films with different incident deposition angles are compared. The experimental results show that the transmittance increases and transmittance peak shifts to short wavelength with increasing incident deposition angle, and that the packing density of TiO2 thin films decrease from 0.801 to 0.341 with incident deposition angle increasing from 0° to 75°. The surface roughness of TiO2 thin films increases with increasing incident deposition angle, and at 75°, it is slightly higher than the surface roughness of K9 substrate. When the incident deposition angle is constant, TiO2 thin films surface roughness decreases with the increase of film thickness.

The ion source electron beam evaporation method was used to fabricate ZnO films with Si as the base and TiO2 as the buffer layer. By further thermal insulation, and annealing treatment at different temperature conditions, different film samples were prepared for the surface morphology analysis and light scattering properties study. The experimental results show that annealing temperature has significant influence on the sample surface roughness, grain size, fractal dimension and other parameters, and the surface morphology analysis is helpful to understand the grain growth mechanisms of film and improve the film preparation process. The intensity and polarization degree of reflected light for different film samples have different response to different polarized lights, which has some relevance to the surface statistical properties of film samples. The light scattering properties study of thin films has some reference value for the study of depolarization effect for weak scattering random rough surface.

To evaluate the dynamic performance of the scanning mirror, a dynamic autocollimation method is presented. The scanning mirror under test and the rotating mirror for target simulation fixed on the dynamic target are skillfully incorporated into the collimated beam propagation path of a dynamic autocollimator, constituting a close loop of optical auto-collimation measurement. The measurement system of performance inspection for the scanning mirror based on dynamic autocollimation is designed, and the calibration method for the accuracy of the dynamic target based on autocollimation is introduced. Experimental results show that the dynamic accuracy of the autocollimation measurement system is ±15 μrad in the 360° rotation range, and the maximum velocity and acceleration available for test are 80°/s and 50°/s2, respectively. The test method and device are used to test the dynamic performances of each axis individually of the scanning mirror adopted in a space laser illumination imaging tracking system. Related test data including wobble of shaft, step response, and continuous tracking are acquired, which will provide reference and help for the performance improvement of the scanning mirror.

A chaotic-laser-correlation fiber-network-faults locator is developed. Utilizing the broad bandwidth chaotic light emitted from a laser diode with optical feedback as the probe beam, it can locate the reflection events along fiber by the correlation characteristics of chaotic light. Measurement results show the faults locator can obtain 0.5 m range-independent spatial resolution, 19.8 dB dynamic range of 4% reflection and lower than -58 dB sensitivity.

A method based on phase modulator is presented to measure retardation of the quarter-wave plate by swinging it without the information of its fast axis direction. In this method, collimated laser beam goes through a polarizer, a phase modulator, the quarter-wave plate to be measured, and an analyzer, and finally incident upon the detector. Its electric signal is amplified and filtered for data processing. The retardation can be attained by swinging the quarter-wave plate, without the precondition of the knowledge of fast axis direction. In experiments, a quartz quarter-wave plate is measured, and its repetitiveness is 0.13° and the reproducibility is 0.17°. Our result is consistent with the one got by the method on the photoelastic modulator when the azimuth of the fast axis is 0°.

The composition of the angle random walk in the four-mode ring laser gyro (RLG) has been researched. It escapes the trouble from the type of random walk caused by crossing the dead band contained in the dithered RLG. By changing the current of the gyro, the time order pulse output of the gyro in different laser intensities is measured. Then the random walk coefficients of the corresponding laser intensities are calculated. According to the feature of the quantum noise, the random walk can be separated into two parts: the random walk due to spontaneously emitted photons and the random walk due to other causes. The experimental results show that the random walk due to other causes plays a more important role in the current status of technology. If the part of random walk could be eliminated or weakened, the value of the random walk would be reduced, and the performance of the gyro would be improved.

The fast automatic focusing equipment of optical imaging detection is one of the most important devices in rapid optical inspection based on machine vision. In order to limit the impact caused by multiple objectives, whose depths of fields(DOF) are from 0.5 μm to 91 μm, and vibration in rapid automatic focusing, a fast detection and compensation of microscope defocus method based on laser triangulation method is proposed. In this method, a macro institution into micro dual driven structure is proposed. It is constructed by the piezoelectric ceramics(PZT) with stroke of 100 μm and direct current(DC) motor with stroke of 25 mm. Based on the structure and laser triangulation, multiple objectives, defocus amount and direction are rapidly detected, cooperating with PZT and DC motor. Experimental results show that the macro-micro dual-drive focus mode can achieve a wide range of auto focusing within 0.4 s, from a low magnification objective (±91 μm) DOF to a higher magnification objective (±0.5 μm), and follow focus in the vibration range (±3 μm). This method meets requirements of the industrial thin film transistor-liquid crystal display(TFT-LCD) automation inspection equipment in broad automatic focusing range, speed and accuracy. It can also be applied in many other fields, such as flat panel display(FPD) inspection, printed circuit board inspection, biomedicine, automatic assembly machines and so on.

Based on noise characteristics of wireless optical communication, atmospheric channel model was founded. Homomorphism filtering technology was applied to four frequency shift keying(4FSK) modulated signal denoising for atmospheric turbulence. Zero-phase digital filter in homomorphism system is desired. When the length of source code was 500 and the signal to noise ratio was 10 dB, the denoising 4FSK signal was demodulated by the zero crossing detection method, and the bit error rate arrived at 7×10-4 with turbulence parameter σ2s=0.1. The simulation results show that homomorphism filtering could reduce multiplicative noise more effectively than the traditional digital filter, and could control atmospheric turbulence to improve relibility of optical communication.

A novel non-return-to-zero (NRZ) to return-to-zero (RZ) format converter for differential phase shift keying (DPSK) signal is proposed based on phase-intensity hybrid modulation and dispersion compensation. Influence on the format conversion of the converter parameters is theoretically analyzed and format conversion of 10-Gb/s degraded DPSK signal is investigated through numerical simulation. Experimental 10-Gb/s NRZ-DPSK signal to RZ-DPSK signal conversion and the bit error rate (BER) performance of the demodulated signals have also been demonstrated. Calculation results show that low duty cycle RZ-DPSK signal with high quality can be obtained through designing the converter. Experimental results show that the power penalty of the conversion is low and the timing-jitter of the RZ-DPSK signal is lower than that of the NRZ-DPSK signal. The format converter can also be applicable to multi-wavelength and differential quadrature phase shift keying (DQPSK) operation.

A reflective optical fiber temperature sensor is highly developed on the basis of the temperature-dependent character of ZnO thin film′s optical absorption spectra. ZnO thin film as sensing material is deposited on a sapphire triangular prism surface by the electron-beam evaporation technique. And then the triangular prism and a fiber-ending located at a convex lens′ focus are employed in the mode of a reflective optical configuration. According to the measurement results, the goodness-of-fit of the sensor′s temperature curve is above 99.3%, and the sensitivity of the sensor is beyond 0.05 nm/℃ when the temperature varies from 300 K to 773 K. Moreover, this temperature sensor is steady enough for a wide temperature range measurement in the experiment, even from 10 K to 1000 K.

A parameter reconstruction method for the physical parameters of fiber Bragg grating (FBG) based on quantum particle swarm optimization (QPSO) is proposed. In the proposed method, the objective function is constructed according to the transfer matrix theory, the physical parameters of fiber gratings are represented in the form of particle, and the optimized parameters are obtained by the particles′ searching in the solution space according to the quantum behavior. When compared with genetic algorithm (GA) and particle swarm optimization (PSO), the proposed QPSO-based method simulates the quantum behavior, which leads to a better convergence performance and a better static-state performance. The simulation results show that, for both uniform and nonuniform fiber grating evolving 100 or 200 times, the proposed method has the reconstruction parameter error of less than 0.5% when the swarm population is 40.

An index-guiding dual-core photonic crystal fiber with quasi-lattice is designed, and its dispersion properties are simulated numerically by the finite element method. The coupling between inner-core mode and outer-core mode of proposed fiber will lead to a highly negative dispersion value around phase matching wavelength. The effects of changing d1, d2, d3, Λ or the number of inner cladding air-hole rings on dispersion properties are investigated. At last, a dispersion compensation photonic crystal fiber at 1550 nm wavelength is designed, which has a peak dispersion value of -2250 ps /(nm·km) with a full-width at half-maximum exceeding 280 nm. Its dispersion-bandwidth product can reach 630 GHz-1·km-1. This fiber is suitable for dispersion compensation in long-distance high-speed optical fiber communication systems.

A novel temperature-independent technology based on π phase of double fiber Bragg grating (FBG) acceleration is proposed. The double fiber Bragg grating accelerometer is designed. The temperature response and acceleration response of the sensor versus wavelength are researched. The configuration and coating of the accelerometer are designed. The temperature-independent principle based on π phase of double fiber Bragg grating accelerometer is analyzed. The temperature response of FBGs and the acceleration response versus wavelength are analyzed. And the analytical formula of acceleration sensitivity is also deduced. Acceleration response and flat range of the accelerometer are analyzed by experiment. Experimental results indicate that precise measurement can be realized in the large range of temperature, and the sensitivity is 15.52 pm/(m·s-2), relative error is 3.06%. The sensor demonstrates extremely linear response, and linear fitting is 99.8%. There is a good flat response at frequencies less than the mechanical resonance frequency, which indicates that the accelerometer has good temperature-independent characteristic and can realize precise measurement.

Based on the actual influence of optical fiber coil received the thermal stress, optical fiber′s crushing stress birefringence in fiber coil is deduced, and the method is proposed, making use of the finite element transient state thermal analysis, to study thermal stress interference birefringence of fiber coil influenced by coating adhesive. Via the simulation computation to the thermal stress disturbance birefringence of typical fiber, the paper concluded that after coating adhesive processing, the fiber coil has a temperature segment that relates to the adhesive parameter, and the thermal stress disturbance birefringence in this segment is smallest, even the sensitivity of temperature change drops to the lowest. Through an actual test to 1000 m polarization maintaining fiber coil, it is indicated that the extinction ratio in this segment is 1.5 dB higher than low temperature section. The match of adhesive material′s temperature characteristic for environment of fiber optic gyroscope is proposed.

The component of fine tracking system for quantum communication is analyzed. The high frame CMOS detector is suit for fine tracking sensor because of the pulse beacon light and the frame rate up to 2.5 kHz by integrative design method. The piezo fast steering mirror is used for fine mechanism. The fine track control loop is analyzed by discrete design and root locus method, with the result of control parameters and system transfer function. The laboratory and outfield 32 km vehicle platform experimental tests are implemented. The accuracy is within ±1 μrad in the static state and ±8 μrad when the platform is moving. By frequency analysis, the disturbance rejection bandwidth is up to 100 Hz.

A NdYAG laser emits two 532-nm laser beams to pump two pulsed dye lasers, respectively. Then one dye laser will emit a 589-nm laser beam for Na layer detection, while the 770-nm laser beam for K layer detection is obtained from the other dye laser. The scattering echoes of these two laser beams are collected with the same telescope, and transmitted by two fibers set in the telescope′s focal plane, respectively. Therefore, we have realized the simultaneous observation of Na layer and K layer by using only one lidar system and have gotten a new and economic detection tool for upper atmospheric Na layer and K layer observation.

We propose to implement simultaneous multi-mode-biased modal wavefront sensor (MMBWS) by utilizing a multiplexed computer-generated holographic element (MCGHE). The theoretical treatments of MCGHE used as MMBWS is presented. To realize the MCGHE, three multiplexed computer-generated holograms (MCGHs) are designed by coding 4, 10 and 20 Zernike aberration modes, respectively. Several critical problems relevant with the designing of MCGH are discussed. The performance of detecting single and multiple aberration modes by employing MCGH is numerically simulated. The results indicate that, within typical range of amplitude, the tested aberration modes can be responded by MMBWS if they are identical with those coded in the MCGH, and the sensitivities corresponding to each mode are different. Once the number of coded aberration modes is small, the sensitivity of the single mode will be large enough; the more the aberration modes are coded , the more severe erasure effect among the aberration modes will exist, thus the sensitivity of both the single and the multiple modes will be affected.

β-phenylethylamine (C6H6-CH2-CH2-NH2, PEA) is one of the simplest neurotransmitters in biological systems. In this paper, conformations of liquid PEA have been explored by mean of Raman spectroscopic and density functional theory (DFT) calculations. The Raman bands of PEA were roughly assigned by the assistance of previous studies and the theoretical predictions. We compare the experimental Raman spectra (at room temperature) and theoretical Raman spectra of all conformers of PEA. The results indicate that six conformers could coexist in the liquid PEA. The temperature dependence Raman spectra of liquid PEA was recorded. The results imply that the anti-conformer was more favorable than the gauche conformer in the liquid PEA at room temperature, which may due to the intermolecular hydrogen bond formed in the anti-conformers.

The influence of the pulse energy and the pulse repetition frequency are measured. The NdYAG pulse laser which wavelength is 1064 nm is used as the excitation source. The characteristics of laser-induced breakdown spectroscopy(LIBS) of metal element Pb in soil are analyzed. The high resolved and the wide spectral echelle spectrograph and intensity charged coupled device(ICCD) are used as the spectral line separation and detector. The experimental results showed that the spectral line intensity increases linearly with the laser energy from 25 to 105 mJ and increases nonlinearly with laser energy from 105 to 165 mJ. The signal to background ratio increases with the pulse laser energy until the laser ernergy is over 60 mJ, then the signal to background ratio is saturated and unchanged with increment of the pulse energy. In the experiment the maximum of spectral intensity is obtained at the repetition rate of 1 Hz. The minimum relative standard deviation is at 7 Hz.