Both individual and unitary imaging properties of a spherical optical array and eflfeots of element input aperture on the imaging properties are discussed. There exist both element diffraction and multi-element interference effect in the unitary imaging process of regular arrays.

In this paper, an interference method for pattern recognition is proposed. A test pattern may be compared with a reference pattern by overlapping the two transparent patterns with a lateral displacement in a coherent beam. If the two patterns are sufficiently similar, regular parallel fringes will modulate the common Fraunhofer diffraction pattern of the two samples being compared. The regularity of the interference fringes is a measure of the similarity between the two patterns. The effect of even a small relative rotation，however, will limit severely the region of regularity of fringe patterns.

Plane waves are usually used as illumination beams during recording and reconstruction processes of the holographic technique for the measurement of particulates. Their usability, however, is restricted by a low diffraction efficiency of the hologram and a large error of the measurement. In this paper, we derive the equations describing recording and reconstruction processes of holograms using sphere wave illumination and compare the two holographic techniques with respect of hologram modulation, diffraction efficiency and the error of measurement. Analysis and experiments show tiiat illumination with sphere waves is better than with plane waves.

We propose a method for making the striped-speckle screen used in a rainbow hologram recording system, which makes the system structure simpler while the reconstructed 2-D image having some single-eye depth perception.

Analytical expressions of coupling frequencies of Raman free-electron lasers are deduced based on the physical image of the coupling between negative-energy space-charge wave and EM wave. Formulas are presented for different operation schemes. Under certain limit conditions, these formulas are reduced to the familiar approximate expressions in literature. Experimental results have borne out our analysis.

By means of integral techniques within normal product we have studied the dynamic mechanism of the generation of squeezed state and its intrinsic relationship with the quantum scaling evolution.

The backward Raman amplifier is shown to be a promising candidate for various nonlinear optical applications. The theory of a backward Raman amplifier with forward scattering feedback presented here can be used for designing small systems. The theory may be used to predict major qualitative features.

There are two side-bands in addition to the central fluorescence from dressed atoms in a strong pump field. When two fairly intense pulses at one of the two sideband frequencies are applied to the dressed atoms at time t and t + T, with pulse areas of π/2 and π respectively, an echo is emitted at time T after the second pulse. It is discovered that in addition to the echo with frequency of the applied pulse, there exists another echo at the other frequency of the two side-bands.

Experimental results of an electron interferometer are presented. The interferometer was set up by installing a Mollenstedt biprism in a JEM-200CX electron microscope. The configuration of the biprism and the optical system of the interference experiments are described in detail. The relation between the maximum number of obtainable interference fringes and the source brightness is discussed.

In this paper the method of density matrix is used to describe two coupled modes. In the case of inverse coupling the density matrix equation of motion is modified by power coupling coefficients caused by random imperfections. The exact analytical solution is obtained.

Using a tunable pulse dye laser, we have made experiments of laser selective excitations in the vibronio band and O-O transition band for hematoporphyrin in both ethanol and 1N HCl at 77K. We have obtained structural fluorescent spectra, which show obvious selectivity for the excitation wavelength. It was found that there are four kinds of isomers of HPD in ethanol at 77 K.

Excimer laserg are noted primarily for their ability to produce high output powers at ultraviolet wavelengths. This ability has made them attractive for lithography application. Excimer lasers are many times more powerful than conventional deep-ultraviolet sources like xenon mercury lamp. An experiment of contact photolithography in the order of a micrometer was demonstrated by using an ultraviolet XeCl excimer laser. An X-ray preionized discharge pumped xenonohloride laser was used to expose a thin layer of resist. The la^er, whioh emits at 308nm, delivered 10MW of peak power in a 2×2 oma beam, A ehromeon-quartz mask with features ranging from 1,0 ?10 gm was employed, tfor contact photolithography. After optimization of the laser power intensity on the resist^ the best laser power intensity for contact photolithography was found to bo about 0.2.Jim2 under our experimental condition. The pattern on the resist shows that linewidths down to 1.5 μτα can be resolved, and 2 .5/xm lines can meet iihe requirements of LSI. This technique has great implications for phoiiolithography because is has high resolutions and ultra-fast exposure times.

Under the action of the fundamental wave of a laser with λ = 1.06/μm, the biological monoJayers of HPD and riboflavin molecules adsorbed on an optical surface can generate SH and TH signals. The beam divergence angle of SH and TH of the HPD layer is 1 mrad, equal to that of the fundamental wave. It is, however, different from that of the ribaflavin layer. The harmonic light beams diffuse into a wide angle.

A system for real-time measurement of vibration using image holography and photodetection is described in this paper. This system can be used to measure samples having rough surfaces with poor reflectance. The photodetection instrument required here is very simple. Some examples of the measurement are given.

This paper discusses the principle of a large-aperture equal-thickness-fringe Fabry-Perot interferometer. Its merits include a relatively low requirement on optical material, high resistance to disturbance and vibration, and high accuracy of fringe location. A transient interferometer has been developed which has a large aperture and can operate in an environment with strong vibration. Interferograms of combustion flames and rocket exhaust plumes were obtained by using this interferometer.

Based on the density matrix equations with 3-j symbol expression, we calculated the intensities and lineshapes of fluoresence signals for two-photon transitions between homonuclear diatomio molecular singlet electronic states, which have a near-resonant intermediate enhancing level. Calculations were made for interactions between a variety of polarization modulated laser fields with three level systems. Signals obtained by the phase-sensitive detection method showed that either the circular polarization modulated method (LPMTPS) could be used to eliminate the Doppler broadening background caused by the adsorption of two photons from one beam. In addition these methods could be used to identify the specific branches of the two photon lines from their ixregnler spectral strnotirres without the need of knowing the upper ΙθτθΙ constants. Signal ratios of eqnal-frequenoy two-photon transitions under circular polarization modulation condition to those with linear polarization modulation wore listed for all the branches with AJ =±2，±1 and 0. Differences of the results might be orders of magnitude fox a resonable large J value. On the other hand signal ratios of two-photon branches in the intensity modulated circulax polarization laser field to those in linear polarization fields (shown in another list) are all in the same order. Furthermore, a table is presented to show the relative signal intensities of unequal-frequency polarization modulated two-photon transitions between various eleotronio states. It might be useful for determining intermediate or upper electronic states of a resolved two-photon absorption line. PMTPS is thus expected to be a usefal method for ruoleonlax spectroscopy or highresolution laser spectroscopy.

The fluorescence intensity of a two-level atom system driven by a two-monochromatic field has been calculated. The results show that the intensity oscillates with time in the long-time limit and the oscillation is the superposition of a series of harmonic waves. The case for maximum oscillation amplitude modulation is reached when one near-resonant monochromatic field acts with an atom, while the difference in frequency of the two monochromatic fields is equal to the Rabi frequency for the first monoehromatic fields is equal to the Rabi frequency for the lirst monochromatic field. We call this phenomenon quanturn beat in resonance fluorescence.