Particle shape affects its physical properties including light scattering. Quantitative knowledge about the shape gets more and more attention in many applications. Shape measurement techniques are summarized on the base of light scattering and imaging principles. A new method combining both light scattering and imaging technique is introduced.

Various atmospheric optical parameters were measured by atmospheric optical parameter measure system, and the preliminary change characteristic of various atmosphere optical parameters of surface layer in Mianyang region, Sichuan Province, China, were obtained by statistical analysis of the experimental data.Structural characteristics of atmospheric optical parameters are known preliminary in Mianyang region, and the results are valuable as reference in further research of laser propagation, remote sensing of atmospheric property, and applications in actual laser engineer.

The structure of the GPS anemometric system, performances of the GPS receiver and method to obtain wind field of atmosphere from GPS position information are introduced. Performances of the GPS receiver are relative closely with accuracy of wind field data obtained. To prove the reliability of the GPS anemometric technique, contrast experiments with the wind profiler and Vaisala are carried out. The experimental results show that the correlativity between the wind data of GPS, wind profiler and Vaisala are perfect and profiles of wind speed and wind direction are close too. However, the mean value of wind speed measured by GPS is larger than that measured by wind profiler and Vaisala. It is important to analyze the reason for the differences and to make correction for the GPS method.

Micro pulse lidar(MPL) is an effective tool for detecting atmospheric aerosol and cloud. To find out the situation in urban subaerial range, the horizontal distribution of atmospheric aerosol and pollutant is presented with MPL developed by us. Two methods, subsection slope approach and Fernald method, are used to reverse atmospheric aerosol and pollutant horizontal extinction coefficient distribution. Results show that it is feasible to calculate horizontal data of MPL by subsection slope approach and Fernald method.

Contrast of star to sky background is an important parameter of star sensor. It determines stellar magnitude detecting limit of the star sensor. Method for calculating the contrast of star to sky background is described. For a star sensor with 3°×3° field of view, 0°and 40°observing angle to detect 6.0 magnitude stars of K and M types, the contrast of star to sky background is calculated as a function of observing height,solar zenith, wave band, and stellar spectral type. Results show that the contrast increases exponentially with increasing of observing height, and the value at 40 km altitude is about one hundred times of that at 10 km altitude. The contrast also increases nearly linearly with increasing of solar zenith, and the value at solar zenith of 80°is about six times of that at solar zenith of 20°for longer wavelength. The contrast in 0.4～1.0 μm spectral range by using B+W090 filter is close to that of 0.6～0.7 μm waveband, and the contrast of the whole waveband almost doesn't vary with stellar spectral types. The results can be used for estimating stellar magnitude detecting limit of the star sensor in the atmosphere during daytime.

An experiment system for determining in vivo fluorescence of phytoplankton with five LEDs with different maximum emission wavelengths as excitation light sources was established. Based on the system,in vivo fluorescence of 10 different dilutions from the same water sample and 24 kinds of water samples from different sources was determined and the linear relationship of fluorescence intensity and chlorophylla concentration was also investigated. The results indicate that blue LED(maximum emission wavelength 442.7 nm) is the most proper excitation light source for determining in vivo fluorescence of phytoplankton,and limit of determination is 0.0278 μg/1(chlorophyll-a). Background fluorescence of DOM, especially the difference of phytoplankton species and fluorescence quantum efficiency, shows significant influence on the determination of in vivo fluorescence. Blue LED has a potential as excitation light source of phytoplankton fluorometry. In order to overcome the influence of phytoplankton species, fluorescence quantum efficient and DOM background fluorescence on in vivo fluorescence, further research should be carried out and proper adjustment methods are needed.

Tunable diode laser absorption spectroscopy(TDLAS) is a new method to detect trace-gas qualitatively or quantitatively based on the scan characteristic of the diode laser to obtain the absorption spectroscopy in the characteristic absorption region. With the combination of TDLAS and the open-path multi-pass Herriot cell, using second harmonic detection and the auto-balanced detection with wavelength modulation respectively, the CO concentration of flame of alcohol blowtorch is measured. The result shows that, comparing with second harmonic detection, the new detection method of auto-balanced detection with wavelength modulation not only improves detectability of 16.3 times, but also eliminates impact from light-intensity fluctuation generated by laser and flame effectively, and could be applied for CO concentration monitoring in many fields including combustion control and component measurement of flame.

With excellent response characteristics, high detection sensitivity and low operational cost, differential optical absorption spectroscopy(DOAS) is a powerful tool to trace concentration variation of trace HCHO.The accurate measurement of HCHO is achieved through improving the ratio of signal to noise and correcting the background scattering light, and the retrieving method of HCHO is developed including the selection of retrieval wavelength, the removing of interfering structures, steps of data processing and the spectrum dealing with nonlinear method. The HCHO concentration retrieved in different wavebands are compared. As a result the band from 314 nm to 332 nm is most suitable for the retrieval of HCHO.

A new safety system of optical fiber sensors for methane measurement is described based on the near-infrared region absorption mechanism. High detection sensitivity of 120 ppm can be achieved by using wave division mutiplexing(WDM) technique, gas absorption cell with rectangular prism and digital match filter(DMF) for the processing of weak signals which measurement accuracy of wavelength can be highly enhanced. Experiments are carried out by using FLED as broadband light source due to the absorption lines of methane within the low loss window of silica fiber. Results show that the stability and accuracy of this system still need to be improved.

In the thermal infrared spectral region, the radiometric temperature of flat non-isothermal mixed pixel varies with the wavelength if we assumed that its emissivity can be represented by r-emissivity. The typical flat non-isothermal mixed pixel composed of soil and vegetation is taken as an example, analyzing the non-isothermal effects on the radiometric temperature of the pixel, and giving a possible method to present the variation of radiometric temperature change. In order to validate the method, simulated hyper spectral thermal infrared dataset is generated. The validation results show that the method can characterize the change of flat non-isothermal mixed pixel with wavelength well and improve the inversion precision of r-emissivity of flat non-isothermal mixed pixel.

The backward scattering ratio is not only an important parameter of detecting seawater backward scattering signal based on airborne lidar, but also a very important optical property of oceanic suspended particles. Based on Mie scattering theory and scattering phase function, it puts forward a formula to calculate the backward scattering ratio. According to Mie scattering theory, the scattering phase function characteristics of alga particles and suspended sands are analyzed, and their backward scattering ratios are obtained too. In addition, the relationship between backward scattering ratio and particle radius and lidar wavelength is discussed in detail. From the simulation results, it can be found that, in the condition of the constant lidar wavelength, the backward scattering ratio of the alga particle increases with the increase of alga particle radius, while the backward scattering ratio of the suspended sand decreases with the increase of suspended sand radius. At the same time, in the condition of the constant particle radius, the two main suspended particles' backward scattering ratios increase with the increase of the lidar wavelength.

To meet demands of the data acquisition and disposal of FTIR spectrometer for environmental monitoring. The software for the real-time data collection is designed using DAQ2005, a multi-function data acquisition card of ADLINK Company, and VC, disposing and displaying of the multi-path interfere signals of FTIR spectrometer on Windows platform. It is convenient for persons to get the experimental results quickly and exactly.

Atmospheric coherent length instrument measures parameters with edge of sun in daylight or star at night with fluctuant arrival-angle. But it can't work at the period of day and night alternating when stars can't be observed with eyes and quadrant elevation of sun is unfit for measuring, so image processing with low signal-to-noise ratio is necessary using suitable infrared filter and high-sensitive CCD while observing star in daylight. The experiment proves that little target can be detected well with frame accumulation and local enhancement method.