The effects of PMMA confinement windows on laser induced shock waves are studied with the use of PVDF gauges made by ourselves. These experimental results demonstrate that confinement of the surface with a PMMA overlay provides an effective method to generate laser induced shock waves of high amplitude and long time duration.

Red chirped optical pulses from a 1.55 μm gain switched DFB diode laser are compressed using a normal dispersion shifted fiber. Under the optimal conditions, optical pulses are compressed from 42.6 ps to 6.8 ps and the ratio of compression is 6.3.

There is a relationship between particle size measurement and particle shape. After studying the diffraction spectrum of non spherical particles, an ellipse particle diffraction model has been put fowerd. By using this model in laser particle size measurement data inversion,the particle size distribution spread can be restrained effectively.

In this paper, the modulation characteristics of a reflective type standing wave acousto optic modulator are analysed theoretically. In order to ensure forming of a strong standing wave ultrosonic field in the acousto optic interaction substance and the higher modulation efficiency of devices by increasing the length of the acousto optic interaction substance and improving the matching network and so on, some methods regarding the design and manufacture of the modulator are proposed. Thereby, a modulation efficiency of 50% for the zero order light of a He-Ne laser under the injecting power of 1 W is obtained.

In this paper, the dynamic equation of laser DNA intenaction turns into Duffing equation (DE), then the solution of DE is obtained by the analysis of primary resonance, superharmonic resonance and combination resonance of two frequency excitation. And therefore some incomprehensible phenomena in the laser breeding are successfully explained.

A new way for detecting medical X-ray image is presented. Instead of the traditional medical X-ray photo taken with a common medical X-ray machine, the method uses an image record plate emboarded in a novel detector to capture the image stimulated by a laser beam. The image is picked up and converted into digital singnal via an A/D converter, then the digital “image” can be displayed on CRT or stored in computer. Compared with the traditional method, the experimental result shows much higher resolution and lesser harm to human being's body. With the great practical value and bright application prospercts, this new method manifests a breaking through in the field of medical application by means of laser and computer technology.

This paper presents the successful use of multiple holographic interferometry in realizing the holographic real time double exposure (time average) interferometry. Observing interference figures of the change of a standard state recorded by double exposure (time average) and “the activity fringe” provided by a real time method, we can compare the change of the standard state with that of states of different times. This holographic interferomety provides a new method for precise real time measurement.

According to the principle of the light attenuation due to absorption and scattering of both the excitation and the fluorescence lights in a deep sectional thick sample, the normalized fluorescence intensity expression is obtained for the light received by an optical system. The mathematical models of the iterative and FFT treatment methods are given. Using computer analog the FFT method is compared with the iterative one in two respects of numerical accuracy and computational efficiencies. Finally, the real image after restoration of the sectional sample is reconstructed by computer simulation with the FFT method.

How to produce the Talbot fractional effect using the fractional Fourier transform is discussed. The optical conditions under which this dual transform will be realized, transform scale factor, image period and operation rule for cascade are deduced, and then an experiment was made to verify the theory. This dual transform is helpful for the design, analysis and calculation of an optical system. An example of application is given in the end.

The microstructure and phase constitution in NiCrSiB alloy were identified by means of SEM, EDAX and XRD, which reveal that the dedrites consist of γ′ (Ni 3Si) and γ (Ni,Cr)  phases while the second phase in eutectic is Ni 31 Si 12 , which forms the matrix in the alloy, with the precipitation particles of CrB, Ni 3B and M 23 (CB) 6 being strengthening phases spreading over the matrix.

A series of technological parameters in controlling plasma in high power CO 2 laser welding were investigated by using a precise declined blow system for assist gas regulating and controlling. The plasma light intensity above molten pool and in key hole was also measured by phototransisters. The plasma control mechanism was theoretically analysed. The results show that plasma control effect was divided into three regions with the change of assist gas flow quantity. No matter what gas species were used, plasma can be best controlled only was the assist-gas operation pressure slightly higher than the metallic vapour pressure.

A heat mode of laser penetrating of thick steel plates has been investigated and the relations between laser power and beam size as well as welding speed have been obtained through energy balance. Meanwhile, the laser beam quality has been discussed. The 4 mm, 6 mm and 8 mm A 3 steel plates have been welded by 6￣8 kW high power from an unstable resonator high quality laser in the experiment. The welding speeds were 3.2 m/min, 2.2 m/min, and 0.9 m/min respectively. The welding depth/width ratio of these samples were more than 2:1 while that of the 6 mm steel plate was 4:1. The technology of laser welding was emphasized. The testing of tensile strength and the experiment of rolling of steel plates through a rolling mill were carried out also.

To bury the substrate defects effectivel, the superlattice buffer layers are fabricated on the surface of the substrate, and a good interface can be gotten. It decreases the threshold current and increases the output power greatly. The quantum well lasers that we fabricated can be operated at room temperature, the wavelength is 778nm and the lowest threshold current at room temperature (CW) is 30 mA, the threshold current density is about 400～600 A/cm 2, the linear output power with uncoated facets is greater than 20 mW, and the width of the spectral line is 5 nm.

Using a dischage pumped KrF excimer laser (FWHM=23 ns) and rate equation model, we studied the saturable absorption character of derivates of linear aromatic tri cyclic dye acridine, and obtained its saturable intensity and remained absorption ratio. A shortening of the KrF excimer laser pulse width (FWHM) from 23 ns to 5.4 ns was realized.

In this paper, the effect of thermal insulator structure in a 100 W copper vapor laser of large discharge tube diameter (6.5 cm) on the length of the lasing region is discussed. The theoretical simulations and the experimental results of two thermal insulator structures are presented.

An ultraviolet laser has been developed from the 632.8 nm line of a Helium Neon laser using an internal frequency doubling method with a Lithium Idate crystal. It allows the generation of continuous ultraviolet radiation at 316.4 nm. By optimizing the optical components,a folded three-mirror resonator gave out up to 1.5 mW UV radiation.

For high power laser of low cavity pressure, a new type of aerodynamic window using jet injection is researched and produced. Experimental study shows that for a φ6.5 mm free aperture, by only using jet injection the sealing pressure can achieve about 0.1 atmophere and the flow of jet injection has no considerable influence on the intensity distribution of the laser beam. As both jet injection and suction are used the sealing pressure can drop down till 66. 5 Pa. The experiment also shows that the sealing pressure can be easily adjusted and stabilized.

Tuning of a compound cavity has been applied to an optical parametric oscillator (OPO) for the first time to our knowledge, which not only reduced the laser threshold, but simultaneously realized narrow linewidth and high power output as compared with a tuning cavity using just the grazing incidence grating (Littman Configuration). The theoretical and experimental results are given as well as a practical experimental device as an example.

The influence of the longitudinal component of the ion ripple electric field on beam wave interaction in an ion ripple laser is investigated by nonlinear numerical simulation. The results show that the longitudinal electric field of the ion ripple has a large influence on the operation of the ion ripple laser, and the choice of the interaction length is very important.

An integral solution of Maxwell equation which can discribe the evolution of an arbitrary laser pulse in a homogeneous plasma is given. Especially, an analytical expression of group velocity of ultroshort laser pulses is gotten by using the integral solution. The relativistic effect is neglected in this study.