This paper presents a new algorithm for fast and accurate analysis of stripe Multiple Quantum Well (MQW) waveguides. The technique is based on the combination of effective index and finite element methods. First, the stripe MQW structure is replaced by an equivalent planar waveguide, using the effective index method to derive the refractive index profile of the planar guide from the original problem. The propagation constants and field intensity profiles of Emnx and Emnv modes for the equivalent structure are then calculated with the finite element method. The results obtained with this technique are given for both the symmetric as well as asymmetric stripe MQW structures with an arbitrary number of wells and different values of the width.

By using effective index and WKB methods, mode characteristics of rib silicon waveguides with trapezoidal cross section are analysed. Equations and cutoff equations of TE modes and TM modes are derived respectively. And by means of the first order perturbation theory, changes in mode propagation constants caused by plasma dispersion effect are estimated.

We have observed the time differentiation effect of KNbO3:Fe crystal and demonstrated the image tracking using this effect. This work is a available exportation for the applications of KNbO3:Fe crystal in the field of photoref refractive device.

This paper presents a study of strong-field autoionization induced by strong smooth laser pulses. Basic equations and a series of analytical expressions are derived. Explicit results are discussed for the autoionization induced by an exponentially growing laser pulse. It is shown that the multipeak splitting is more evident in the high-energy photoelectron spectrum than in the low-energy spectrum.

The ablation parameters of laser plasma, especially line-shaped laser plasma have been discussed in detail, and their scaling laws with laser intensities have been demonstrated by theoretical analysis and calculation of experimental results directly using the ion measurement for the first time.

In this paper the advantages of the realisation of a far infrared (FIR) free electron laser (FEL) are shown: it requires an electron beam with less stringent characteriaties, less expensive and it is unique source for nonlinearity and coherence in FIR. The dependence of the FEL performance en parameters of the electron beam and undulator is described. For a given beam emittance there is a specific wavelength below which the gain rapidly becomes very low. The important physical phenomena in the FIB and possible uses of FIRFEL are given in broad outline, these studies could be important for the possible development of a THz electronics.

Laser output pulse with 100 mJ energy and 15ns duration was obtained by using a phase conjugation resonator consisting of a normal mirror und a phase conjugation mirror formed by stimalated brillouin scattering (SBS) in liquid. The output energy of different resonator parameters has been measured. Distorttion correction capability of this cavity has also been demonstrated by using a phase plate.

The two-photon absorption (TPA) of colloidal CdS semiconductor microerystai-lites has been studied by using a single-beam transmission technique. For different crystallite sizes of 5.5～11.0nm, the TPA coefficients of 1.31 to 5.24cm/GW are measured and the corresponding x(3) of 2.8×10-12 to 1.1×10-11 esu are obtained at wavelength of 510.6nm. The dependence of crystallite size on TPA has been analysed, and the theoretical prediction is in agreement with the experimental result.

Based on its atrong magneitcally induced birefringence, this paper deals with the research of the magneto-optical bistable characteristics of a ferrofluid thin film. An optical transmission model is proposed and an experimental system is set up to analyse its dependence on the system parameters. Experiments show that the ferrofluid thin film behaves good characteristics of optical bistability and can be used as ultra-long wave optical waveguide devices.

The light-induced scattering effect in Ce:LiNbO3 crystal was investigated experimentally as a function of temperature and analyzed theoretically by using the band-transport model and beam coupling equations. The experimental resultes were in accord with the theoretical ones.

In this paper, we report the first study on interaction of ethanol with molocular oxygen pre-adsorbed on a polyorystalline silver surface by optical second harmonic generation (SHG) in an ultrahigh vacuum system. It is found that the interaction consists of two process, one is the enhanced adsorption of ethanol induced by molecular oxygen: the other is the reaction of ethanol with molecular oxygen. From the temperature spectrum measured by heating the adsorbed system, we obtain the desorption temperature of reactant and interactive strength of ethanol with molecular oxygen.

This paper deals with the application of the moire technique and lau effect in the navigation leading mark. The moire fringes can be seen at an infinite distance, and its shape not only shows the direction to be corrected but also gives the deviation, distance in definite quantity.

The calibration of optical wedge space in Fizeau laser wavemeter is the precondition for the measuring laser wavelegth accurately. The number of calibrating wavelengths for the calibration of optical wedge space is studied in this paper. The analysing results show that the number of the calibrating wavelengths mainly depends on the selection style for the calibrating wavelengths and the error range of the optical wedge space.

Based on the theoretical analysis of two elliptically polarized light fields, the features of two elliptically polarized light fields which orthogonalized each other (levorotation and dextroroyation) and a circular polarization and a linear polarization light field are disused. Polarization method for moving interference fringes is introduced.

Pumped by 514.5 nm Ar ion laser, superfluorescence was observed in a 3 m Nd-doped silica fiber. The maximum output power is 6 mW with the emission linewidth-of 3 nm. A good agreement is found between experimental; data and theoretical fits.

The Raman spectrum of folded longitudinal acoustic phonon modes of ZnS-ZnSe strained-layer superlattice have been reported. In the region 10～90cm-1, three doublets were observed at room temperature.

The atomic beam velocity distribution of Gd atomic metastable levels, 215cm-1 533 cm-1 and 999 cm-1 were measured by means of laser induced fluorescence method. Their lifetimes are deduced from the change of the velocity distributions at two different probe areas along the beam axis. The experimental results show that this is a very simple, sensitive and effective method to measure the lifetime of atomic metastable level.

In this paper, by the way of extended average level (MCDF-EAL) model of relati-vistio multiconfiguration Dirac-Fock code. We have calculated 44 fine-structure energy levels of 2s22p2, 2s2p4, 2p5, 2s22p23s, 2s22p23p configuration and 33 transition wavelengths of 3s-3p from N-like VXVII, Or XVIII, MnXIX and FeXX ions which may be the candidates for lasing action. The calouladed values of 3s, Sp configuration for VXVII, CrXVIII and MnXIX are first predicted.