This letter reports the results of thermal fixing of holographic grating in BaTiO 3 crystal, predicating the critical temperature of the formation of complementary ionic grating, the relation between the speed of ionic grating formation and temperature, the relation between the ionic grating formation and the diffractive light oscillation and the effect of different cooling ways on the efficiency of thermal fixing. Thermal fixing of holographic grating with high efficiency is also achieved. We have also observed some new interesting feature of erasing in high temperture and present explanations of the experimental results.

The identification of the chaotic optical system with BP feedforward neural network supported by a modified BP algorithm is suggested. The feasibility of this suggestion was demonstrated with computer simulation of the identification of the Bragg acoustooptic bistable & chaotic system. The computer simulation result shows that, the three layers foreward neural network, if trained with the chaos speedup BP algorithm, is indeed a fine identifier with less training iterations than usual. Thus it could be used to reconstruct the dynamics of the chaotic optical system with its output time series very efficiently.

From the point of view of logic operation implementation of mathematics morphological binary image operations using logical array isproposed in this paper, and some basic morphological image operations′ minimized logic represatations are given. The experiments of morphological image operation have been demonstrated in the simulated architecture. Since the feedback loops are not necessary, so it is simple and easy to execute.

The rectangular band pass reflection hologram (RBRH) which has high diffraction efficiency in a wide bandwidth Δλp (about 10 nm to 20 nm), has some particular significances in the applications of reflection hologram. In this paper the manufacturing technique and experimental results for RBRH are described. The efficiencies are greater than 99% and 95% respectively and the bandwidths Δλ p are more than 10 nm for two types of RBRH.

A Circular disc refractometer with linear output response of photo-electrical signal to liquid refractive index has been developed. The multiple reflection within the circular disc provides a design feature to reduce the influence of non-total internal reflection and significantly improves the measurement linearity. In addition, the circular disc refractometer can achieve quite good linearity even for non-parallel light beams.

Precise determination of strains in ZnO doped LiNbO3 proton exchanged optical waveguide using double crystal X-ray diffraction is reported in this paper. It is found that the waveguide layer contains uniformly distributed three dimensional strains and the variation of lattice constants in the waveguide depends closely on the waveguide orientation.

By using thermal conductivity equation, the index change resulted from linear absorption induced thermal effect in Z-scan measurments with pulse laser is studied. The conclusion is consistent with previous experimental results.

A orthogonal phase locked detection method used in interference single mode fiber gyro is described in this paper. This method using double reference signal can separate gyro signal from noise. The noise level of the gyro signal can be reduced, and phase shift feedback can be used in the gyro. The zero drift of the gyro reduces to 0.2 deg./h.

Resolving the Lorentz equation of electron motion in the undulator which has a field error, we obtain the change of transverse velocity of electrons. Through a Fourier transformation, we can find the influence of all kinds of field error in undulator on spontaneous spectrum. Choosing the BFEL parameters, we simulated the effects on FEL spontaneous spectrum due to field errors, and obtained the acceptable condition of all kinds of field errors in undulator.

In this paper we reported the experimental results of the erbium glass minilaser. Under free runing regime, we studied the influences of the reflection coefficients of the couple output mirror, the gasses pressure of the pump lamp, and the total capacitance of a storage bank on the output energy. By using a lithium niobate electrooptic switch, we gained giant pulses output of 8 mJ energy. And laser output pulses of 12 mJ energy and 80 ns duration was obtained by using a prism Q switching.

The photon statistics in free electron laser fields is analysed by means of LLP transformation in this paper. And the perturbation solution is presented.

High order harmonic spectra in an intense laser field are obtained by salving the time dependent schrodinger equations with two level atom model. The results are agreement with experimental data. This model can be used to study the effects of laser frequency, laser intensity and ionization potential of media on harmonic generation.

The AO Q switched Nd:AYG laser end pumped by two CW 1.5 W laser diodes is reported. The repetition rate of 30 kHz is obtained, and the peak power with the pulse width of 12 ns is 12.1 kW at the repetition rate of 1 kHz.

Laser diode end pumped Nd:YVO4 laser with high efficency 1.064 μm laser output is repoted. The CW laser output was TEM00 mode linear polarization. Up to 837 mW of output power was obtained with 1.5 W pumping power on Nd:YVO4 crystal. Pumping threshold was 140 mW. The slope effieicny of the laser was 61.5% and total optical conversion efficiency was 56%. Electrical effieincy of 15% was obtained.

High order harmonics induced by resonance absorption in a laser irradiated target is calculated by using a capacitor model. The possible application of the high order harmonics of ultrashort intense laser pulse as a source of short wavelength coherent radiation is discussed upon calculated results.

The angles of reflection and transmission from interaction of electromagnetic waves with a relativistic underdense ionization front are investgated. First, according to a phase matching condition of electromagnetic wave on the stationary boundary surface, we find the refelection and transimission angles in the front system with a static ionization front. Then using the transformations of wave vector and frequency we get the corresponding angles in the laboratory system in which the ionization front is moving at relativistic speed. The obtained results are discussed.

The saturation of third relativistic coherent harmonics generated by ultrahigh laser in underdense plasma was analysed; A mistake inprevious anlysis was pointed. The saturation amplitude and dephase length were calculated and the factors that affect the dephase length was discussed.

The photochromic property and colloidal formation mechanism of the sodium chloride crystal material colored by γ ray irradiation and electron beam bombardment are investigated systematically. The F→C conversion can be created efficiently by irradiating the colored crystals with a few laser pulses at 448 K. The sizes of the produced colloids augment with the increase of the colored doses. A new colloid whose absorption band located at 625 nm is produced and observed for the first time in the colored sodium chloride crystal. The C→F conversion can be carried out efficiently at 532 K, so the reversible conversion from F center to C center is realized. The F→C conversion is realized mainly by means of the agglomerating of mobile defects produced by the photoionization of F and F' centers under the F band laser irradiation. The brief physical interpretation is given on the colloidal formation mechanism.

Using coupling mode equations, the characteristics of Mach Zehnder Wavelength Division Multiplexer (WDM), such as wavelength multiplexing interval, isolation ratio and output power, are analysed. The temperature stabilization is discussed. The analysis and experiment of its wavelength tunability are presented.

The optimization for fabricating large cross section Si/GeSi/Si single mode rib waveguides with RF heated CVD method is discussed. The optimal fraction x of Ge in GeSi layer defined by the necessity of single mode, numerical aperture and critical thickness is between 1～3%. The height and width of rib must be also limited by the single mode and large cross section, The etched rib side walls are slope due to the Si crystal structure. The best initial width of rib is 5～6 μm. The etching and polishing solutions must ensure the rib side walls and end faces to be mirror. The measured results show that the performance of the optical waveguides improred remarkably. The output light field is increased and the propagation losses is less than 0.5 dB/cm.

We study the statistics of scintillation at the airborne receiver for space earth space link by analysed the modulatory mechanism of atmospheric turbulence and terrain scattering on propagating laser beam. The scintillational statistics are governed by the joine effects of atmospheric turbulence and terrain scattering (such as terrain, sea and forest). The probability density functions of scintillation for the terrain, the sea surface and the forest, the two scattering terrain model was obtained, in which the probability integral is made by the method of steepest descent. The joine distribution of geneval Chi-Squared distribution for scattering terrain and atmospheric turbulance is found flatten markedly and its peak shifts to the low end of normalized irradiance.

Directly calculating expression of angular shift of a Gaussian beam reflected by absorbing medium interface is given, which can be applied to any incident angle and does not diverge at Brewster angle. This expression is symmetrical for both p and s polarization. Setting g1=n 1 and g2=0, we will obtain the angular shift of s polarization beam.

A kind of distributed feedback (DFB) diode laser module was developed for the use of Amplitude Modulation Cable Television (AMCATV) transmitter. The module is an InGaAsP/InP Double Channeled Planar Buried Heterostructure Distributed Feed Back (DC PBH DFB) diode laser emitting at 1.3 μm in butterfly peckage with an internal isolator. The modules provide CW linear output power of 2.5 mW and low distortion.

Properties of an optical quality circular metallic hollow waveguide are discussed and the technique for fabricating such a waveguide is decribed. The waveguide with gold or silver as the waveguide cladding material exhibits the characteristics of low propagation loss, transmission insensative to waveguide bending and misalignment, and capability of transmitting high power light from visible to far infrared. It is demonstrated that transmission of He Ne laser is independent of the refractive index of the liquid filled into a gold hollow waveguide, and this characteristic greatly extends the nonlinear waveguide applications. The mechanism for a “hollow fiber” in the 10.6 μm spectral region is discussed and results of propagation of CO2 laser through a gold hollow waveguide are presented.

The absorption spectrum of a new crystal Nd:S FAP was measured and a broad effective absorption band and two strong absorption pesks at 575 nm and 804.5 nm were observed. By using a Xeon flash lamp pumping, laser operation has been demonstrated at 1.059 μm with threshold energy of only 150 mJ, slope efficiency of 1.25% and a peak power of 10 MW/cm 2. The emission spectrum, output energy and pulse width were presented. The prospect of Nd:S FAP crystal for low threshold and high efficiency miniature laser was discussed.

Direct writing of fiber Bragg gratings (FBG) by an excimer laser using phase mask copy method is reported. FBGs written in B Ge co doped single mode silica fibers with Bragg wavelength of 1541.80 nm, bandpass of 0.2 nm and central reflectivity of 95% have been observed.

Zeeman modulation magnetic rotation laser spectroscopy (ZM-MRS) was first used to seperate the magneticc rotation signal (n +-n -) effectively from the laser background and the high order terms of magnetic rotation signal in visible region. It not only has very high sensitivity, high signal to noise ration and no absorption background and also can suppress the rotational spectrum with high quantum number for simplifying complex electronic spectra. In this paper the theoretical analysis of this technique is simulated by computer. The results are fitted well with the experiment. This spectrscopic method is valuable for measuring free radicals and helpful for assignment of molecular spectrum.

Vacuum ultraviolet radiation from argon fluoride ionic excimer excited by x ray from laser producd plasma was observed near 125 nm for the first time. The experimental results are coincident with the calculated ones.

A new method for diamond nucleation on the mirror surface of nondiamond substrates using C 60 films as the intermediate layers is presented. The polycrystalline diamond films have been deposited on Si(100) mirror surface and on SiO 2 scratching surface without higher substrate negative bias pretreatment prior to diamond growth by microwave plasma chemical vapor deposition. The diamond grains of resulted films show cauliflower like small crystalline aggregates, and the morphologies of the grains show cauliflower-like small crystalline aggregates, and the morphologies of the grains show (100) faces in SEM images.