It is proposed that an Er doped fiber bistability device with fiber gratings may be used as an all optical switch or a digital signal amplifier of low power and high speed. And, the device is one dimensionally integratable along the fiber. The operation, characteristics, and parameters of these devices are analysed and calculated to give a design principle.

The criterion number X which equals 1.357 is adopted in the design and data processing of the laser FD based particle sizes. The classical Mie light scattering theory is used in the design of the laser particle sizers to extend their lower size limit. According to the theory, the criterion number X and the factors influencing X are discussed in detail.

Based on the light scattering principle, a novel method for particle size analysis is presented in this paper. As distinguished from the traditional light scattering based laser particle sizers, a white light is used as the light source and the scattered light energy within only one solid angle is collected. The particle diameter and its size distribution are then acquired from the inversion calculation. Theoretical analysis, numerical simulation as well as the experimental investigation are presented and discussed.

A novel method for laser beam smoothing by a rotating random phase plate is presented. A random phase plate for CO 2 laser was made, and satisfactory results were obtained. The experimental results coincide very well with the theoretical analysis.

The Modulator′s bias point setting is very important for optical fiber AM CATV externally modulated transmission. In this paper it is concluded that when the bias point drifts away from the best bias point, CSO (Composite Second Order distortion) is influenced severely, whereas CTB (Composite Triple Beat distortion) is not influenced. The related formulas were deduced for PAL/D 550 MHz CATV transmission, the maximum voltage deviation from the best bias point is less than 10 mV. The experimental results agree well with the theoretical analysis.

Based on a system theory point of view, Fourier transform properties of multi lenses are discussed. The focal length of an added phase compensating lens in a compact 4 optical system is recalculated according to the specific system. The length of the system is reduced once more to about 1/4 of the original system length by using two Fourier transform telephoto lenses. Finally, a design of the compact optical 4 f system is given.

In this paper a fractal hypertexture model combining the thought of hypertexture with fractal theory is presented. The synthesis method of natural scene images using noise and turbulance functions with fractal apperarance is given. Rendering is accomplished by ray tracing. Then, we are allowed to render the ditigal holograms by controlling some parameters. The results indicate that this method is quite efficient for simulation of natural scenes.

A plasma sprayed Ni WC coating was cladded on the ZA111 alloy surface by a 5 kW CO 2 laser. Using SEM and X ray analyses, the microstructure of the laser melted zone was investigated, and the wear resistance of the laser treated samples was measured. Experimental results showed that the Ni Al intermetallic compounds Al 3Ni, Al 3Ni 2, AlNi and Ni 3Al are dominant in the laser melted zone. Meanwhile, some WC particles were melted during the laser melting, and they separated in carbides during the cooling. The microhardness is very high in the laser melted zone. The wear resistance of laser melted samples is 2.83 times high than the aluminum matrix and 1.75 times high than plasma aprayed samoles.

The surface of TiAl alloy is nitrided by CO 2 laser gaseous alloying with nitrogen. The experimental result shows that the nitrided layer consists of TiN and TiAl phases. Dendrite TiN distributes in the nitrided zone homogeneously. The cross section micro hardness of the material changes continuously. The nitriding level increased with the reaction time increasing. The higher laser energy density, the deeper nitrided layers. The depth of the nitrided layer and the surface micro hardness are 200 μm and HV700 as laser power density of 3.35×10 5W×cm-2, scanning velocity of 300 mm×min-1, and nitrogen pressure of 0.35 MPa are used. Under the same experimental conditions, the nitriding level and the depth of the nitrided zone of TiAl alloy are lower than those of titanium.

In this paper, the optimum working parameters, such as Cl 2 molar flowrate and reaction length for the optimally designed JS 1 were determined via one dimensional calculation. And the optimum specific Cl 2 molar flowrate was experimentally obtained. The experimental results are in good agreement with calculated results. Finally, the dependence of performance of JSOG on buffer gas is discussed.

An experimental study on the relation between repetition rate, pulse width and average output power of a CW pumped Nd:YAG laser Q switched by a Cr 4+ :YAG absorber was carried out. Stable Q switched pulses with duration of 120￣900 ns wide (FWHM) and repetition rates between 2.2 and 10 kHz were obtained by using different absorbers of different initial transmissions. Modulation in the Q switched envelope was found and an explanation was given.

In the study of a solid propellant combustion driven CW CO 2 gasdynamic laser system built, the mixing properties of the solid propellant gas and high pressure air, and the working properties of the experimental system have been simulated by the numerical method. It may be helpful to obtain comparatively ideal laser working media and high power laser output.

An analytical expression describing dynamic frequency shift (“reflection chirp”) of the DFB semiconductor laser due to residual end reflection of the attached electroabsorption modulator is derived. By a computer simulation, we find that the optical pulses through transmission in the dispersive optical fiber are narrowed and distorted due to this “reflection chirp” which is well agreed with experimental results.

The experimental results for the nonresonant third order nonlinearity of the polymer films doped with acceptor donor azobenzene derivatives are reported. Comparison of both third order nonlinearity of the samples and the molecular structure of azobenzene derivatives are performed. It is found that a larger third order nonlinearity corresponds to a stronger acceptor and donor electron capability in the molecules, and attaching the side group to the benzene ring may increase the molecular dipole moment, hence the third-order nonlinear susceptibility. Tt is demonstrated that third-order nonlinearity of the samples is produced mainly from molecular reorientation of photoinduced cis-trans isomerization.

A novel method of wavelength conversion based on four wave mixing in a dispersion shifted fiber using a spectrum sliced fiber amplifier light source is demonstrated. Utilizing the wavelength region around the zero dispersion wavelength of a fiber, a coherent light modulated by 5 Gbit/s RZ signal is converted with a conversion efficiency of -24 dB。

It reports a series of new optical organic molecules of cinnamylidene acetophenone derivatives. We have synthesized eighteen compounds, and measured their powder second harmonic generation (SHG data 6~19 I2ω/I2ω urea), λ cut-off (450~510 nm) and λ max (320~380 nm). This series of molecules are found to have larger nonlinearity and shorter cut off wavelength than the chalcon derivatives. The experimental results indicate a promising application in low power lasers.

The chopped waveshapes of an avalanche transistor and krytron electrooptics gates are compared by streak camera measurement. Also, the waveshape of a laser multicascade amplifier is measured. A 2~3 times compression of pulse width in the laser amplification process is indicted.

A recoil pressure model of the photoacoustic effect in solid is developed. The relation between the photoacoutic signal and the laser power density is studied to test the model. There are a maximum and a minimum of the photoacoustic signals with the increase of the laser power density.

Carbon cluster ions have been produced by laser ablation and stored in a RF ion trap. Taking the advantage of mass selective storage and long storage time of the ion trap, we have studied the collision induced dissociations and collision association reactions of C + n cluster ions through the mass selective storage in the ion trap. According to the findings of collision induced dissociations and the variations of enthalpy before and after collisions, the conditions that collision-induced-dissociations can happen to cluster ions are obtained. And, the range of endotherm and the dependence of collosion -induced activations on trapping parameters of cluster ions are analyzed. Based on the analyses, the processes of association reaction of ions produced through collision参考文献-induced-dissociations of cluster ions are rurther studied. The method of calculation of effective collision cross section is also investigated.