A new apparatus used for optical image subiraotion wiih periodic whiie light linear sources is proposed. Provided thai filament interval,grating spatial frequency,periodic polarization spatial filtering are matched each other, the brightness of coded image will be increased greatly. Beoause of high redundenoy of -the system, the inflnenoe of pola-riza-fcion degree and phase inhomogeneiiy of sheet polarization filter oould be considerably reduced. Bo, high SNR subtraofcion outpxii could, be obtained. In this paper, property of coded image and requirement for ilie system are discussed with spatial coherent imaging theory. Procedure of light transmission and filiering, shifting of carrier are calculated with matrix method. Decode method by using optics and electronics is disoribed.Finally, desirable experimental result is presented.

A new apparatus used for optical image subiraotion wiih periodic whiie light linear sources is proposed. Provided thai filament interval,grating spatial frequency,periodic polarization spatial filtering are matched each other, the brightness of coded image will be increased greatly. Beoause of high redundenoy of -the system, the inflnenoe of pola-riza-fcion degree and phase inhomogeneiiy of sheet polarization filter oould be considerably reduced. Bo, high SNR subtraofcion outpxii could, be obtained. In this paper, property of coded image and requirement for ilie system are discussed with spatial coherent imaging theory. Procedure of light transmission and filiering, shifting of carrier are calculated with matrix method. Decode method by using optics and electronics is disoribed.Finally, desirable experimental result is presented.

The paper describes degrees of freedom in an imaged plane when its object plane under the illumination of partially coherent light is imaged through an optical system. It also shows the transfer mechanism of degrees of freedom through an optical system by means of both imaging integral equaton and illuminative integral equation. The conclusion is that the aberration of an optical system will not change the degrees of freedom.

In this paper an annular aperture method for laser speokle photography is proposed. The autocorrelation of an annular aperture function is oaloulated. The intensity distributions of the diffraction halos single exposure speokle patterns recorded by annular apertures with various internal to external diameter ratios η(,η = 0, 1/2, 8/4, 5/6, 7/ 8)are given, and these distributions are normalized by total diffraction intensity. It is shown that the intensity distribution of the diffraction halo is of rotational symmetry and the intensity at the border of tlie diffraction halo is increased remarkably,while the intensity at the intermediated region of the difFraotion halo may be on a fairly high lever when an annular aperture with, an appropriate ratio η is used. Therefore not only filtering in all directions at the border of the diffraction halo oan be carried out to achieve isothetios with high sensitivity along arbitrary direction，but also the widest variable sensitivity region can be obtained. An example to demonstrate this method is given. The experimental results agree very well with the theoretical analyses. It can be seen from the experimental results that 5/6 is the appropriate internal to external diameter ratio because consideration of high sensitivity, wide variable sensitivity region and short exposure time is given in this case.

Two-photon lasers and laser amplifiers are studied by using the rate equations. The steady solution is obtained and its stability is analysed. The time evolution of large deviation from the steady solution is studied by using computer simulation. The population inversion and the trigger input must exceed certain thresholds to operate a two-photon laser. The method for producing giant-pulse is discussed. The possibility of building a pratioal two-photon laser is analysed basing on the known data, A Doppler-free two-photon laser needs much lower threshold but much more serious frequency matching among the atom system, cavity and the trigger input. Such a Doppler-free two-photon laser could find applications in laser spectroscopy and in the accurate metrology. Two-photon laser amplifiers distort the input waveform seriously. This distortion depends strongly on the input intensity.

A new method for producing tunable ns duration pulse trains was presented in refrenoe[3]. The oscillating-disoontinuous amplifying model for investigating tunable ns pulse trains is set up in this paper. It consists of three groups of the rate equations, which represent three stages respectively』that is the oscillating,"the resting and amplifying stage in the process of pulse trains formation. Based on this model, the gain of medium, amplitude and spectral behavior of the pulse trains are calculated,the process of forming and developing pulse trains is investigated. The results indicate: (1) The gain coefficient fluctuates across the threshold in a period of the pulse trainSjit appears as tlie gain sainration. (2) The degree of pulse modulation and the looking efficiency of frequency decrease with the time in some degree, while within 0.4μs the degree of the pulse modulation is better than 98%, the looking efficiency of frequency is better than 95%. The pulse amplitude of narrow band operating approaches to that of broadband operating, it means that, the energy loss caused by narrowing spectrum is only a few. The theoretical results are in agreement with experiments basically.

A new non-linear Q-switch was discovered first in our experiment. It synthesizes advantage of crystal and dye Q-switoh, and is one kind of ideal Q-switohes and look mode elements.

In this paper, a proposal of obtaining near-monoenergetic atomic beam deflection by resonant light pressure is offered. The near-monoenergetic atomic beam deflection may be used to analyse velocity distribution in atomic beams, to measure the life-time of excited states in atoms and to verify the theory of photon statistics.

The two-photon resonance ionization experiment for the detection of ultra-low concentration of atomic cesium is described. Complete saturation of photoionization was achieved. The number of atoms detected with each laser pulse was measured to be 5.3?l04. By using a tunable dye laser we have achieved the two-photon resonance ionizations the first photon excited cesium atom from ground state 62S1/2 to the excited state 72P1/2, and the second photon ionized the excited cesium atom.

This report describes the experimental researches on the polarization Oharaoteristios of symmetric GaAs-GaAlAsP double heterojunotion lasers, and analyses the mode-competition processes of these lasers. The experiments showed that semiconductor laser is emitted spontaneously and does not indicate optical polarization characteristic when it is biased under the threshold current. When it is biased above the threshold current, the laser for thin active layer of d = 0.15?0.40枓m ig generally observed only in fundamental order mode, and TE mode polarization is predominant. At this time, polarization selection is dependent on Fabrj-Perot cavity facet (cleaved face) mode reflectivity E0. But TM mode is saturated at the threshold, the onrrent applied to the laser above the -fclixesliold is used to enhance the TE polarization when the active thiokneas d is larger than 0.4^m, the competition, between TE and TM mode, fundamental order and higher order mode will appear. TE mode enhancement will result in TM mode decay, or TE mode decay provides TM mod? enhancement. In this case, polarization selection depends on both the mode confinement factor Γ and facet reflectivity Rm. TE mode, TM mode, fundamental-order mode and higher-order mode will possibly appear. Besides, polarization charaoteristio depends closely upon the internal crystal defect and inhomogeneous crystallization for the aotive layer of laser as well as the partition ratio of injected carrier.

In this paper, the effect of mis-alignment on path difference in stable plano-concave resonators (sjmply called plano-concave cavities afterwards), whioh are widely used in practice, has been discussed by means of matrix methods. The method is suitable to the common spherical cavities in principle. For convenience of analysis, however, the plano-concave resonators are only discussed within miniature mis-alignment. After comparison with experimental data and theoretical results three conclusions are obtained: (1) When the plano-concave resonators are correctly aligned, the effect of mis-alignment on path difference will be the most sensitive. (2) The plano-concave resonators have the "self-alignment" effect within miniature mis-alignment, and the experiment shows that the path difference will fluctuate with increase of mis-alignraent angle. (3) If the angles of mis-alignment are less than 1", the effect on path difference for plano-concave resonators drop down to 3 χ 10一9, and if the angles of mis-alignment could be further reduced to 0.2", the effect on path difference will drop down to 1×10 10.

The ionization of F2 center in LiF and NaF crystals are explored in this paper. Experiments show that F+2 centers are created in LiF crystals with F2 center when they are irradiated by Hg-lamp, pulse Xe-lamp and D. 0. carbon arc. And F+2 centers are created in NaF crystals with F2 center when they are irradiated by pulse Xe-lamp and W-lamp. The problems about the efficiency of two-step ionization are discussed in the paper. The analysis shows that the way of increasing the efficiency is: it is necessary

A new method of preparing the raster plate with optical fiber has been developed. The parameters and measurement result of the element of raster plate show that a total of micro-lenticular elements is 2.25?104. The pitch is 0.4mm. The photographic resolving power of the optical fiber raster plate for a single lenticular element is 110 line-pair mm-1, the focal length 0.3mm. The raster plate has total information capacity of 1.089×107 bit.

X-ray spectral lines emitted by high temperature plasma can be taken by means of crystal spectrograph in laser-plasma experiments. Spaoe-integraied and space-resolved x-ray crystal spectrograph developed and used in onr laboratory are described in this paper. X-ray diffraction crystal is "the main pari of the speotrograpli。 The integratod roflection coefficient, peak diffraction efficiency7 crystal broadening and hoinogonoity of ihe crystal have been deiermined experimentally. In addition, linear dispersion and instrumeni broadening have also been estimated by some experiments. Tho oharao ieristio curves of the X-ray film have been obtained by several mothods. The windows of ihe spectrograph are aluminized Formyar films which, have high transmission in soft X-ray region. This is one of the distinguishing features of our spectrograph. Some typical space-integrated and space-resolved spectra of He-like and Η-like ions of sodium and silicon in 5~13 A obtained in our experiments are presented, in Lite end of this paper.

An improved design relevant to the traditional Michelson interferometer is proposed in this paper with a purpose of obtaining better sensitivity and measuring accuracy. This is an effective approach to improving the sensitivity and measuring accuracy under the same condition for the Michelson interferometer.

Absorption and fluorescence spectra of Mn2+ in phosphate, fluoro-phosphate and fluoride glasses have been studied. Combining with the result of the ESR experiment, the coordination state of Mn2+ is discussed. It can be considered that in the three kinds of glass Mn2+ ions are situated in octahedral symmetry. Theoretical calculation com forms to the experiments. In order of phosphate - fluorophosphate - fluoride glasses, the ionic contribution of the chemical bond between the transition ions and ligands iincreases gradually with the replacement of Oa~ by F—, and the site tends to more regular octahedral symmetry. The red fluorescence has been observed in all the three kinds of glass. Tii? fluorescence peak position shifts to shorter wavelength by changing the glass from phosphate to fluoride. Iron exists in fluoropliospiiate glass as Fes+ and and its absorption spectrum has been studied as well. Combining also with the ESR experiment, we consider iV+ ions axe located in octahedral symmetry.