By using the method of numerical simulation and experimental observation,focused uniform beam spreading induced by atmospheric turbulence and thermal blooming is analyzed. The scaling relations between the laser propagation effects and characteristic parameters described atmospheric propagation effects are obtained. Based upon these scaling relations,we can efficiently estimate atmospheric propagation effects and learn the performance of a particular system design for various environmental conditions as well as for conducting laser system design optimization.

Recent investigations carried out at the Laboratory of Optical Physics,Institute of Physics,CAS,on the propagation of intense femtosecond laser pulses in air is presented. A long-distance plasma channel is formed with a length of several hundreds meters. Four methods are developed to diagnose the plasma channel. Strong third harmonic emission is observed with a maximum conversion efficiency of 0.3%. The filaments distribution is optimized for applications using a pinhole with different diameters. The lifetime of the plasma channel is prolonged up to the order of microsecond. The filamentation process and the surpercontinuum emission are closely related with the initial chirp of the laser pulse. Triggering and guiding of large gap discharges in air by plasma channels opens promising perspectives for lightning control.

The 61-element adaptive optical system for the 1.2 m telescope of Yannan Observatory had been upgraded and in operation for astronomical observation. It is made up of the fine tracking loop,the higher-order correction loop and the high resolution imaging system.In order to improve the low-frequency compensation performance,the fine tracking system,which is used for correcting the vibration error of the telescope and the tip-tilt error induced by atmospheric turbulence,consists of two cascade control loop. The higher-order correction loop consists of a Hartmann-Shack wavefront sensor,a 61-element deformable mirror,and a high speed digital wavefront sensor. The wavelengths for the Hartmann-Shack wavefront sensor and the imaging observation range from 400～700 nm and 700～1000 nm respectively.The 61-element upgraded adaptive optical system for 1.2 m telescope of Yunnan Observatory is briefly described. The performance on the 61-element upgraded adaptive optical system is analyzed. Furthermore,the observational results for the stars are presented.

A 1064 nm direct detection Doppler wind lidar has been completed successfully in Hefei,China. It was developed to detect three-dimensional wind profile in the low troposphere using the double-edge technique. Specification and overall structure of the lidar system are introduced. The structure and operation principle of its main subassemblies are presented.Some preliminary wind profiles are shown and discussed. The results show that this lidar system has high stability.

A new method is presented to calibrate lidar constant. Atmospheric aerosol optical depths(AOD)were measured by solar radiometer and lidars were used to acquire backscattering signals from aerosol free-loading regions 35 to 40 km altitude. Atmospheric model provides molecular scattering coefficient. Lidar constant can be calculated according to lidar equation. After lidar constant was calibrated using solar radiometer,aerosol optical depth can be determined with lidar return signals from 35 to 40 km altitude according to lidar equation. A good agreement between lidar measurements and solar radiometer measurements shows that our method for AOD measured by lidar is feasible. This method can be used to measure AOD on daytime and nighttime.

The position sensitive photomultiplier tube(PSPMT)was introduced to the experimental measurement of laser beam wandering induced by atmospheric turbulence. Based on the operating principle of PSPMT,the effect of the detector's placement to the output signal was analyzed. The position and gain calibration was experimentally performed in order to obtain the position coordinates of the incident light in the active area of PSPMT. The experimental measurements show only one sample can't express the position of the incident light correctly when the light is strong and the beam width has the order of centimeter. So the statistic mean position of some samples for the same incident light was used to denote the real incident position. The highest sampling rate and sampling points combined with signal frequency were taken into account to determine the number of sampling points to be averaged.

The Fourier shear interferometry(FSI)based on the lateral shearing interferometer(LSI)is studied. The frequency distribution of the fringes in the Fourier domain is analysed. Meanwhile,the influence of the filter's bandwidths(a=5,6,9,11)on the reconstructed results is also discussed. The numerical simulation results demonstrate that the bandwidth of filter should be narrowed suitably when the turbulent effect is strengthened for the improvement of the FSI.

The spatial distribution characteristics of the scintillation of a Gaussian-beam propagating in a weak turbulent atmosphere are studied with a numerical simulation algorithm. The evaluation procedure of the scintillation index is investigated thoroughly. It is found that the off-axis scintillation index increases with the off-axis distance and the minimum is on the optical axis. The agreement between results of numerical simulations and the theoretical results validates the reliability of both methods.

The principle of wind measurement for a direct detection Doppler wind lidar developed with a Fabry-Perot etalon is described. The measurement error of the system is affected by the receiving beam divergence angle. The numerical calculation for the Doppler wind lidar system has shown that the percentage error is increased slowly to 5% for the beam divergence less than 1mrad. The analysis results for the measured beam divergence angle indicate that the error in the velocity dynamic range is less than 0.6m/s up to 5 km.

A generalized formulation of signal on each pixel for a wind detection lidar based on Fizeau interferometer and CCD is derived. System parameters is optimized through numerical simulation. System wind error is below 0.16m/s at the altitude from 0 to 3 kilometers. Least square fitting method and gravity method are used to retrieve wind velocity. The analysis shows that least square fitting method can only be used when the velocity is small. Gravity method is analyzed and the method error is corrected by a new method. After correcting,the error due to the method is below 0.25m/s at the range of wind velocity from－30m/s to 30 m/s.

By using Mie scattering lidar,return signals in cloudy,foggy and sunny weather are measured. In the process of inversion,selection of the logarithmic ratio of aerosol backscatter-to-extinction has a large effect on extinction coefficient. For cloudy weather,when the logarithmic ratio of aerosol backscatter-to-extinction changes from 0.7 to 1.0,the change of aerosol extinction coefficient is 5 times,for sunny weather,the change is near 3 times,whereas for foggy weather,the change is not much. Using visibility data obtained by meteorological observation,corresponding logarithmic ratio of aerosol backscatter-to-extinction is obtained. A new type of method for deciding logarithmic ratio of aerosol backscatter-to-extinction based on weather conditions is proposed. The corrected results are close to the real atmospheric conditions.

Angstrom wavelength exponents can well reflect the size of atmospheric aerosol particles. Raman method supposes less parameters but acquires higher precision when compared with Mie method. The L625 Raman-Mie dual-wavelength lidar which has been developed for observations of tropospheric aerosol optical properties is presented,then the tropospheric aerosol wavelength exponents are calculated and analyzed using data from L625 lidar. Some typical characteristics of tropospheric aerosol optical properties are observed and discussed.Results indicate that L625 lidar is reliable for the measurement of tropospheric aerosol wave-length exponents.

Most of SO2,NO2 and O3 monitors in the measurement network are point monitors at ground level that yield no information about the spatial distribution of SO2,NO2and O3. The information is conventionally obtained with ballon-borne sensors. However,this method provides only poor temporal and spatial resolution. A mobile differential absorption lidar(DIAL)system for atmospheric pollution measurements has been developed at the Anhui Institute of Optics and Fine Mechanics,the Chinese Academy of Sciences. It allows 3D-measurements by using a steering unit,and can measure four kinds of pollutants in atmosphere,SO2,NO2,and O3. By using this lidar system,SO2,NO2 and O3 measurements have been performed in Bejing from December 27,2001 to January 27,2002.It was the first measurement of air pollution monitoring in Beijing by DIAL. Comparison with the simultaneous measurement performed with SO2,NO2 and O3 analyzers showed good agreement.

In order to testify the mensurability of high SO2 concentration and the variety of SO2 with AML-2 mobile lidar,a measurement is carried out near a power plant. The fourth harmonic of Nd∶YAG laser is used to pump CH4 and D2 gas cell,and the first Stokes Raman-shifted wavelengths of 288.38 nm and 289.04 nm are obtained for SO2 concentration measurement. The maximum of SO2 concentration about 1300 ppb is got in the smoke way.2D mappings of SO2 distribution are also presented which are detected on the windward and the leeward of the power plant. It comes to a conclusion that the exhaust gas from the power plant truly effects the environment nearby. The detecting ability of the AML-2 lidar on SO2 is also proved.

Detecting the trace gas CO2 reliably is becoming more and more important due to greenhouse effect and climate changing. Using the Raman lidar for monitoring the atmospheric CO2 concentration is an advanced technique. The Raman lidar system based on stimulated Raman scattering(SRS)process is presented,and the basic theory for Raman lidar is introduced. Moreover,the experimental detecting system and its specifications are presented. The retrievable method of Raman lidar backscattered signal is expounded and the law of CO2 density profile is obtained. The concentration for atmospheric CO2 varies about between 350 ppmv and 400 ppmv.

The design and experiment of a Raman lidar system for measurement of atmospheric CO2 are presented. 354.7 nm third harmonic of Nd∶YAG laser is transmitted with 60 mJ pulse energy and repetition rate of 20 Hz．Receiver employed photomultiplier tube with quantum efficiency of 25% and 200 MHz photon counter,and it detects Raman backscattering signal 371.66 nm(shift 1285 cm－1)from CO2. Combinatorial filter is used to reject interference presented by 354.7 nm intense Mie-Rayleigh backscattering and 375.4 nm Raman backscattering from O2。Other wavelength radiation was excluded to enter photomultiplier tub. The interference from O2 is approximately 1% of the anticipated CO2 signal.

The basic principle of DIAL for ozone measurements is given. The structure of mobile lidar system(AML-2)is presented. Some typical results of ozone profiles and spacetime distributing diagrams are shown at vertical,horizontal and two dimensions scanning aspects. These results are analysed. This may have great significance for the study of surface ozone and atmosphere pollution detecting.

Lidar is a high precision instrument. Now we design a new control platform which based on virtual instrument technology. By using virtual instrument technology,we assemble all the control and measurement instruments of lidar into one software platform which make control more flexible and reliable. Instrument drivers simplify instrument control and reduce test program development time by eliminating the need to learn the programming protocol for each instrument. LabWindows/CVI is a software development environment for C programmers. Access powerful function libraries for creating data acquisition and instrument control applications. The platform can real-time measure and analyze signal. Contains instrument control and data acquisition.

The nanometer technology combining with the near-field optics create a new subject-nanophotonics. Near-field optical probes and near-field optical microscopes used as research method make the research of nanophotonics expand fast. Some new devices and techniques of the field of nanophotonics are reviewed,and the progresses in quantum computation and near-field optical chemical-vapor preparation are introduced.

By constructing auxiliary functions and ordinary differential equations,we have obtained some new exact traveling wave solutions of the nonlinear coupled KdV equations which include soliton wave solutions and periodic solutions.

By the discrete position representation method,the vibrational-rotational levels of some bound-state and the Franck-Condon factors of rovibrational transitions in non-adiabatic approximations for diatomic molecules are calculated. The results are in accord with the literature values very well. The relative errors are all smaller than 1%. These results may be useful for the experimental study of rovibrational spectra of the diatomic molecules. The computational procedure can be popularized to the numerical calculations for other diatomic molecules and the multi-dimensions quantum systems.

Methane is a major constituent of natural gas,mine atmospheres,and gas fuels.On account of its inflammable and explosive characteristic,gas explosion is a big problem in natural gas station and mining industry. Tunable diode laser absorption spectroscopy(TDLAS)is a gas detection technique provided with high sensitivity,high precision,high selectivity,and rapid responsibility,which has large development in recent years. Wavelength modulation spectroscopy(WMS)is an important technique of TDLAS. In this paper,the WMS technique have been used to detect the methane,and prove the intensity of 2f signals is in direct proportion to the methane concentration in the concentration range between 0.04% and 10%. This WMS technique can be used in methane detection in industrial occasion,and based on these an instrument of methane detection can easily be integrated.

We propose a scheme for teleportation of an unknown three-atom W state without the Bell-state measurement. Firstly,we prepare an unknown three-atom W state by the resonant interaction between the atoms and the cavity. Then a quantum channel is prepared by sending two atoms through a single-mode cavity field,and driving them by a strong classical field at the same time. During the interaction between the atoms and the cavity,the states of these atoms are evolved. After the interaction,we prepare the EPR states,which form the quantum channel. Finally,we implement the teleportation of the unknown three-atom W state using the way of preparing the quantum channel. During the teleportation,the effects of thermal field and cavity decay are all eliminated. The success probability is 1.0.

The condition of negative refraction is analyzed by using the plane-wave method,then the negative refraction at the interface of air and two-dimension photonic crystal is numerically simulated by FDTD. It is concluded that the light wave refracting negatively always has the negative group velocity. Finally,the conditions of negative refraction at different frequencies are compared in detail.

Under on-resonance condition and with a time-dependent atom-field coupling,we study the entropy properties of the field interacting with a V-type three-level atom,and discuss the effects of the atom-field coupling coefficient and the different initial field on the field(atom)entropy at length. The results show that the different statistical properties of the initial field will lead to the change of the field(atom)entropy. When the atom-field coupling coefficient changes slowly,the speed of atom entering the statistical state is slowed;When the atom-field coupling coefficient changes rapidly,the oscillating frequency of the evolution of entropy speed up.

For the general time-dependent inductance-capacitance coupled circuits,quantumclassical correspondence and the quantum fluctuations are studied by using the Heisenberg correspondence principle. Through the wave functions and exact solution of equations of motion in Heisenberg picture,the classical solution is derived from quantum solution in the limit of large quantum numbers carrying out the average over the initial phase in the matrix elements,quantum fluctuations of the charges and magnetic fluxes are obtained. When the inductances in the circuit increase and the capacitances decrease exponentially with time,quantum fluctuations of the charge and current decrease exponentially with time;When the inductances and capacitances in the two component circuits are equal to each other and time-independent,it is found that the coupling capacitance tends to reduce the quantum fluctuations of the electric current and the coupling inductance tends to reduce the charge quantum fluctuations.

There are lots of factors,such as the refractive index of dielectric,the number of periods,the thickness of defect layer,the width of spectrum line et al.,have effects on the bistable threshold of nonlinear microcavity. However,the red shifting in cavity-mode plays a very important role. We theoretically analyse and numerically simulate the effects of red shifting on the bistable threshold. The red shifting should be first considered in studying bistable threshold.

Blue host material 9,10-di-(2-naphthyl)anthracene(ADN)was doped with Aluminum(Ⅲ)bis(2-methyl-8-quinolinato)4-phenylphenolato(BAlq3),and the concentration of BAlq3 was changed,then structure of ITO/NPB/ADN∶BAlq3/Alq3/Mg∶Ag were fabricated in the vacuum. The impact of energy-match and BAlq3 dopant concentration on the carrier injection,transport,recombination and the color purity of the devices were analyzed. The experiment results show that BAlq3 dopant influence the current density,luminance,efficiency and color purity of the devices. When the BAlq3 dopant concentration is about 25%,the luminous efficiency is 1.0 lm/W,the spectrum at 440 nm,the CIE chromaticity(0.18,0.15),and the half life of unseal device is about 950 hours,which achieve both the high efficiency and good color purity.

ASON which is the development trend of the next generation optical transport networks has a key characteristic which is the rapid and efficient survivability strategy. We describe the optical network survivability and analyze the multi-domain network and multidomain routing. We present the scheme of multi-domain survivability at last.

Aiming at improving the sensing system compatiblity and anti-jamming ability,in the loop cavity of fiber-laser,based on the F-P resonator comprised of FBGS to interrogate sensors and the central wavelength tuned by the beam elements is proposed and demonstrated.The all-optics sensing system has the advantages of high resolution,low inserting loss and compatible completely. When the sensing signal of the FBG is locked,the feedback system can track and demodulate it automatically. To confirm the theory,using a sensing and demodulation gratings that get the laser output at the central wavelength 1554.32 nm which is fit with our target.

Based on the conventional MEM theory,it has been exactly calculated that coupling efficiency of the 2-d grating for long-wavelength(14.7μtm)QWIPs. The result shows that the coupling efficiency is highest when grating period D=4.7μm,grating depth h=1.45μm and d/D=0.707,and it also has been proved by geometrical optical method. Moreover,the distribution of optical field has been calculated in the diffractive grating.