Non-scanning 3-D range-gated imaging lidar can improve the detection capability, image quality and distance accuracy of the system by suppressing back scattering and removing fuzzy distance. The non-scanning 3-D range-gated imaging lidar system composed of commercial products is introduced, and the experimental system is tested. Results show that the system range resolution is 1.5 m at 40 m range indoor, and target shape and distance information can be acquired accurately. The system range resolution decreases to 3 m at 960 m range outdoor, however, target can still be identified. Finally, the system's shortcomings are pointed out.

Theoretically analytic methods and numerical simulation algorithms used to investigate the propagation of a partially coherent beam in turbulent atmosphere are briefly reviewed. Theoretical methods include extended Huygens-Fresnel principle, cross-spectral density function, coherent-mode decomposition, effective beam parameters and ABCD ray matrix. The simulation algorithms contain random phase screen, coherentmode recomposition and random optical pulse method. Several typical types of partially coherent beam and beam spreading of a partially coherent beam in free space are introduced. Main results as to beam spreadzing, optical intensity fluctuation and angle-of-arrival fluctuation in turbulent atmosphere are summarized.Problems that should be further studied are presented.

Development of K-distribution method and the mothod of calculating the atmospheric absorption by K-distribution are introduced. It mainly discusses the present research status of Kdistribution method at home and abroad and its application dealing with real atmospheric problems.

In order to reduce the error of range differential absorption lidar for detecting atmospheric CO2,theory of detection accuracy is analyzed and the error of differential absorption detection system is simulated.Based on 1.6 μm optical fiber laser, the accuracy of coherent system is calculated. Results show that the signal to noise ratio of echo is higher and error of gas concentration is lower when the differential absorption cross section gets bigger and the spatial resolution gets worse. If the differential optical depth of CO2 is equal to 0.55, the percent variation of error is the least and the accuracy is the best. With the height increasing, the accuracy of 1.6 μm optical fiber laser coherent detection system is decreasing. When the height is lower than 1 km, the atmospheric CO2 variation of 34 ppm can be detected.

A self-developed laboratory simulation system on turbulent flow is introduced. The characteristics of temperature structure of the stable boundary layer(SBL) and convective boundary layer(CBL) are simulated by controlling temperature of the top and bottom of the laboratory water tank. Warm atmosphere flows through the surface of cool atmosphere uniformly to the SBL, and flat terrain surface are uniformly heated to the CBL. Vertical profiles of mean temperature and heat flux are measured in the SBL and CBL conditions,also the evolution of mixed-layer depth is presented. Results show that the characteristics of temperature structure of the SBL and CBL from laboratory model are in good agreement with the observed result from the atmospheric boundary layer.

Lidar ratio problem is discussed for atmospheric aerosol particle dectection. Lidar ratios at 0.532 μm for slightly non-spherical continental-average aerosol particles are evaluated according to up-to-date database of aerosol optical and micro-physical properties. It is found that the non-sphericality has an obvious impact on lidar ratios. The results could be applied in practical lidar detection of atmospheric aerosol particles.

Based on four-year observation of integrated water vapor and surface vapor concentration ρ0 on sunny days at Hefei station, the scale height H of the atmospheric water vapor was statistically analyzed.Results indicate that annual variation of H is obviously marked by summer(winter) the highest(lowest)value, and the discrepancy between spring and fall is feeble. The degree of correlation between mean seasonal values of H and mean seasonal values of ground air temperature is excellent. The diurnal variations of H exhibit two-trough shape for different seasonal classes, with maximal value at 16:00 and minimum value at 08：00 and 20：00, respectively. Mean hourly values of H are proved to having excellent negative correlation with mean hourly surface vapor concentrations ρ0 during 06：00～16：00.

The methodology is described for detection of SO2 in flue gases by differential optical absorption spectroscopy(DOAS). The basic principle and data analysis method are introduced. The selection of wavelength range during the measurement is also discussed. Measurement of SO2 was carried out at different spectral resolution(0.6 nm, 0.7 nm, 1.8 nm) respectively. The influence of spectral resolution on the result was analyzed. DOAS method analyzes high-frequency part of absorption spectroscopy, and it can avoid influences of the interferences such as fume, vapor. It is proved to be a good method for detecting the flue gas.

There is an increasing need in many fields for fast, sensitive, and selective gas detection based on laser spectroscopy with the development of society. Quantum-cascade lasers are ideal light sources with its special characteristics of power, tuning and capability of operating in or near room-temperature. Quantumcascade lasers and a typical mid-infrared laser spectrometer based on a room-temperature distributed-feedback pulsed QC laser are described in detail, and the bright future of QC lasers used in gas detection is also showed.

The application of coal mining gas multipoint monitoring with tunable diode laser absorption spectroscopy(TDLAS) technique is studied. The principle and design scheme of real-time monitoring of multipoint gas concentration system which based on spectroscopy absorption principle is analyzed. The TDLAS technique, distributed fiber sensing technique and time division multiplexing detection technique are integrated to achieve optical sensing of multipoint gas concentration. Considering the requirement of real-time measurement, a new inversion method by insetting a calibration cell with standard concentration gas into the optical path is introduced. The system's performance is tested by measuring gas of different concentrations. The detection limit is below 60×10－6. It proves that the scheme is feasible, and the technology has characteristics of real-time, successive, non-intrusive and fast measurement, so it can meet the requirements of coal mining gas monitoring.

The self-made ground-based multi-axis differential optical absorption spectroscopy(MAX-DOAS)is introduced. Two-dimensional CCD array is used in this system, which enables the images of optical signals obtained from different elevation angles distributing in different area in CCD. Thus it is possible to be detected simultaneously for atmospheric trace gases from different elevation angles. The performances of the detector and imaging spectrometer, such as offset, dark current, noise, linearity, resolution, wavelength range, are tested.Monitoring results of O3 from different angles are presented. Results show that the MAX-DOAS system can satisfy the need of atmospheric monitoring.

In order to realize precise and real-time detection of SF6 in gas-insulated switchgear(GIS), infrared laser absorption is studied and analyzed. Based on the strong absorption characteristics of SF6 at infraed wavelength(10.55 μm), the relation of SF6 concentration and its absorption characteristics is studied at this wavelength, and the relation curve is given. This method provides a theory foundation for quantification detection of SF6 in GIS.

Fourier transform infrared(FTIR) spectrometer takes significant role in monitoring the earth's environment and atmospheric pollution. Michelson interferometer is the main part of FTIR spectrometer. In order to provide uniform motion of the interferometer mirror, stability and repetitiveness of sampling, a servo system based on ATMEL89c52 single-chip is described. With the help of laser interference and white light interference, it achieves not only uniform velocity but also precise position through PID controlling, which satisfies the spectrometer's motion demand.

A room-temperature widely tunable mid-infrared laser spectroscopy system based on difference frequency generation(DFG) developed in our laboratory recently is reported. The system employs two nearinfrared diode lasers ranging in 1490～1580 nm and 1058.1～1060.8 nm as signal and pump sources, respectively.PPLN crystal is used as nonlinear mixer unit, and the continuous coherent light output tuning from 3.2 μm to 3.7 μm is achieved combining quasi-phase matching technique. The output bandwidth characteristics of the system is studied experimentally and compared with the theoretical calculation.

A freshwater biomonitor system is designed to perform in situ monitoring of the organism behaviors in freshwater. The freshwater biomonitor measures and analyses different types of behaviors of aquatic species based on the registration of changes in a high frequency alternating current, rapid and sensitive behavioral responses of the indicator species, caused by the movements of organisms in the test chambers, monitoring changes of toxicity in the freshwater finally. Experiments show that the freshwater biomonitor is easy to use and stable in working, and it can perform in situ measurement to changes of toxicity in freshwater accurately.