A novel method, edge technique, for measuring Brillouin scattering in water is proposed for the first time in this paper. Combined with the application of Brillouin lidar in remote sensing in the ocean, an actual detecting system based on bromine and iodine absorption cells is suggested, and the response of the system is given. Finally, the advantages of the edge technique are discussed.

Based on the classical Mie scattering theory, the influence on the measured results which is caused by the inputted refractive index in data processing of the small-angle forward scattering laser particle sizer is investigated by means of POWELL inversion algorithm. The error would be within 0.002% in the case that the inputted refractive index equals exactly the natural one of the measured particles. Otherwise, when the inputted refractive index is in the range of (2.0,4.0) the magnitude of the error would be much less than in the range of (1.1,2.0). So, it comes to the conclusion that the value of the natural refractive index should be inputted in data processing if possible and a value larger than 2.0 should be believably chosen as the inputted refractive index if the natural refractive index of the measured particles is unknown.

Take fractional Fourier transform of two identical objects. The focal distance of the lens would be acquired by measuring the spacing of fringes formed by spectrum interference. The experimental setup of this method is very simple. And it has the advantages of being easy to operate and easy to control automatically, and of higher accuracy. It has a practical virtue in optical measurement.

The fabrication of a KTP Pockels cell utilizing the effective EO coefficient of the crystal is reported. Compensation of the static birefringence of the switch was achieved by temperature turning. Then the device was successfully used to slice and shape the Q-switched laser pulses.

Optical limiting in tetrabromo-2,3-naphthalocyanine Zinc(II) is studied by using a double-frequency pulsed Nd:YAG laser system with a wavelength of 532 nm, pulse widths of 8 ns and 23 ps, respectively. Under the condition of high transmission 93%, the experimental result shows that these new materials have good optical limiting characteristics.

This paper presents a novel miniature system for measuring modulation transfer function (MTF) of CCD. This system consists of a miniature interferometer which can generate frequencies-variable sine grating patterns, data collection and transfer subsystem, software and hardware for data processing. The measured results show that the spatial frequencies of grating patterns generated by the interferometer can be continuously changed ranging from 0.2 to 80 line pair/mm with an error lower than 1 %. The modulation contrast of patterns is close to one. We have used the sine grating patterns generated by the interferometer as targets to measure the MTF of CCD array. The results are satisfactory.

The three-dimensional visualization of a quasi-stable flow field needs two-dimensional projections. In flow field interferometric tomography, the conventional method of fringe tracking, by which a few solitary one-dimensional projections are obtained, can only evaluate the 2-D distribution of the field on a limited number of cross-sections. A new method combining the Fourier analysis and the improved multigrid iteration is proposed to extract 2-D projections from interferograms of the measured field in various directions. On the basis of 2-D projections the real 3-D field reconstruction can be reached. In the last section of this paper, an experiment of asymmetric temperature field measurement using rotaryF-P interferometer is reported and some cross-sections of the reconstructed temperature field are given to prove that the methods of sampling, processing and reconstruction algorithm illustrated in this paper are effective.

The modulation transfer function(MTF) to characterize the quantity relationships for imaging quality of an underwater laser imaging system and its influence factors is discussed and its approximate formula is given. The relationships of MTF with spatial angle frequency, target distance and the received view angle are derived. The results show that imaging quality can be effectively improved by using synchronous scanning technology with narrow view.

The influence of irradiation manner of a YAG-pulsed laser on the microstructure and cracking behavior of claddings was characterized. It follows that the microstructures of the cladding may not show a visible change after multi-irradiation with the YAG-pulsed laser beam,however,multi-irradiation do promote the appearance of cracking on claddings. The tendency of cracking of the same cladding may increase with the increase of the number of irradiation. The formed cracks show a feature of along grain boundary like hot cracking. Additionally,more heat input during the process may increase the tendency of initiation of the re-heat cracking in the substrate alloy as well.

This paper proposes a laser carving mathematics model based on computer graphics. In addition,the optimal laser carving method is given and all the algorithms are proved excellent in practice.

The microstructure of laser clad Ni-Cr-B-Si-C alloy is composed of blocky CrB type chromium carbon borides , Cr7C3 type chromium boron carbides, cellular-dendritic γ-Ni solid solution and various eutectic products. Either an eutectic of γ-Ni+M23C6 or an eutectic of γ-Ni+nickle borides forms depending on the local composition. γ-Ni/Ni3B stable solidification and γ-Ni/Ni2B metastable solidification take place at the same time because of the rapid solidification involved in the laser cladding. Both Cr7C3 and M23C6 contain a high density of twins resulted from stress associated with rapid solidification. In addition, an amorphous phase was found, the γ-Ni surrounded by the amorphous phase exhibited a tweed contrast, suggestiv of a modulated structure.

A CO2 laser of 800 W and TEM00 mode has been successfully used for welding of the diamond tools. Through numerous experiments, a study of the effect of technological parameters, such as laser power, welding rate, vertical focal point and offset, upon welding quality of diamond tools is made and the optimal technological parameters of laser welding are obtained. The depth/width ratio being about 2 mm, and the maxium penetration depth about 1.2 mm are reached. The bond strength and the loading capacity of the diamond tools are greatly increased by the laser welding.

Starting from laser rate equations including influence of energy level relaxation, influence of laser medium on the high power laser amplifier was studied in detail. An analysis of increasing efficiency of the amplifier was presented. The result obtained would be useful for the optimum design of the amplifier.

The dependence of self-mode-locked Ti:S laser pulses on the intracavity net negative group-delay-dispersion is investigated in detail in this work. The results show that the central wavelength spectrum, bandwidth and duration of laser pulses will change with the movement of intracavity prisms. The multi-peak structure of spectra is observed and explained theoretically. Also, a formula of pulse duration is pointed out in this paper. The shortest pulse width up to 14.6 fs is generated in our laser.

Using the double curved target coupling and multipulse pumping techniques, combined with the novel line focus system, the Ni-like neodymium soft X-ray lasing experiment was carried out on Gekko XII at Institute of Laser Engineering, Osaka University. The intense soft X-ray laser at 7.9 nm was obtained with relative lower pumping laser energy.

A highly efficient diode-laser-pumped intracavity frequency doubled and Q-switched Nd:YVO4 laser is presented. Q-switched operati on of the laser was realized by using an intracavity KTP crystal, which was also used as a frequency doubling crystal in type II phase matching for generating green laser. In CW operation, a green output of 115 mW and optical-to-optical conversion efficiency of 14.4% were observed at 800 mW pump power. In Q-switch operation, a pulse width of 5.45 ns and a peak power of 74 W of the green laser were achieved at a 100 Hz repetition rate.

The elementary theory of optical information processing is reanalyzed by using wavelet theory in this paper. First, wavelet theory is used to reanalyze the Huygens-Fresnel principle, then an ideal of wave-front filtering is brought forward, the foundation of wavelet optics theory is thus established preliminarily. On the base of the theory, phenomenon of optical diffraction from a single slit, round aperture, grating, and so on are analyzed according to the ideal of wave-front filtering. The filtering in spatial domain, spatial frequency domain and a system of optical formatting imagines are also analyzed. The results show that it is feasible for the method of wavelet analysis to be used to study the problems of optical information processing, and it is more accordant with practical circumstances.

Based on the concept that there is a π phase jump property in the boundary wave, the diffraction of the plane wave and the spherical wave through an aperture is analyzed by means of wavefront diagram. This method can be used not only in the case where the aperture radius a is much larger than wavelength λ, but also in the case when a is comparable to λ. It is shown that many properties of diffraction in the Fresnel region can be obtained. As an example, a method to put the point of unit Fresnel number to infinity is suggested and demonstrated. The results of this report confirmed the existence of the π phase jump concept and its value in practical applicalions.

The effect of pump fluctuations on mode-competition of a two-mode laser with saturation effects is studied. By means of a linear stability analysis, some conclusions have been obtained. In strong coupling, if pump fluctuations are absent, the mode-competition effects are such that one mode can build up a stable oscillation and the other is suppressed. However, if pump fluctuations are present, two modes may build up stable oscillations at the same time. In weak coupling, if pump fluctuations are absent, the mode-competition effects give rise to two modes which may build up a stable oscillation. However, if pump fluctuations are present, one mode may be suppressed.

Based on the hydrodynamical model of optics and the equivalent Gaussian beam method,we analyse the statistical propagation behaviors of a paraxial beam transmitting through a thin lens. A new method was introduced to deal with the lensed aberration,and the aberration action on the geometric beam quality factor was discussed at the end of this paper.