A method for imaging of reflection-type objects through distorting media via degenerated four-wave mixing is discussed. The (experimental results of imaging a reflecting point and an object through two phase-distorting layers are presented.

We have developed a bifilar helix wiggler used in a Raman free-electron-laser, and have measured its operating characteristics. By using this wiggler as a pump source, we have obtained free-electron laser radiation and oarried out preliminary parametric studies.

The kinetic processes in Ar/He/Fa mixtures excited by fast discharge have been analysed. A mathematical description, which could reveal the characteristics of paths in the kinetic processes, hag been given based on a simplified kinetic model. Characteristics of paths in Ar2F* formation processes have been studied by comparing the experimental data with the results of numerical calculations.

The interactions among R35, T34 and S54 processes in a six-level system were studied. Near the cross point of the resonant curves of these processes in the multiphoton resonance diagram of the six-level system, such interactions should be very strong. We found theoretically that in the case of off-resonant-pumpnig, the interactions among these multiphoton prooesseg should also lead tosplitting of the laser spectral line, which is called off-resonant-pumping AC Stark effect. Because tJhe influenoes of saturation eifeot and electric dipole transition enhancement effect were not the same for different mnltiphoton processes^ oontributions of different nmltiphoton processes to the o￡f-resonant AC Stark effoot could be distinguished by the injection of FIR signal into the system

The opaque sample and transparent alexandrite crystals have been analysed by different techniques such as fluorospectrometer, X-ray fluorospeotrometer, ESCA. The measured date support our previous suggestion about the formation mechanism of the melt aging named by Lienard. Then transparent crystal can be grown with good reproducibility. Inolusions and dislocations in the crystals have also been investigated. Since then high quality alexandrite crystals have been grown.

This paper describes the optical properties of prime-color fluorescent lamps popular in recent years. The main purpose is to improve the luminous efficiency and colorimetrio properties of fluorescent lamps. The prime-color phosphors used in the fluorescent lamps are mixtures of three kinds of phosphors emitting narrow bands of red, green and blue lights respectively. The relative spectral power distribution(SPD) of the prime-color blend of phosphors is a weighted linear combination of the SPD of individual.

The Combined Plane-Cylindrical Mirror Analyzer (PCMA) hag the advantage of high transmission and the possibility of second-order focusing, just like the conventional cylindrical mi ror analyzer (CMA). In the POMA all fountain electrons emitted from the specimen (electron source) on the cylinder s ooaxis will be focused behind the specimen on the axis after travelling through 180 degrees. By using PCMA as the electron energy analyzer in a scanning electron microscope (SEM), the working distance of the SEM magnetic objective lens could be shortened, and its spherical abberation reduced as compared with non-coaxial gun type CMA, thus the primary electron beam current density oould be increased. As a result, the sensitivity of the scanning Auger Mioroprobe (SAM) might be enhanced. Furthermore, the structure within the irrer cylinder of PCMA is much simpler than the conventional CMA with coaxial gun.

The development of a picosecond GaAs photoconduotive switch is reported. The switch consists of a miorostrip transmission line formed on Cr-doped semi-insulating GaAs with a small gap (-20μm) in the stripline. As the source of optical pulses used for preliminary evaluation of the switch, a synchronously pumped Rh6G dye laser was used. The rise time of the signal observed on a sampling oscilloscope was 120 ps and the FWHM was 230ps. We measured the dependence of peak voltage of the switched electric pulse on the energy of the incident laser pulse for a bias voltage of 30 V and incident energy range of 38~220 pJ.

With a linearly polarized laser beam of wavelength λ= 1.06μm acting on the monolayer of the laser dye 2-(p-Dimethylaminostryry L)-Pyridyethyl iodide (DASPI) and the organic molecules N, N -diethyl-pseudoisocynanine chloride (PIC) on a smooth surface made of fused quarz or glass, the SHG by DASPI or PIG can be detected easily. By changing the direction of the linear polarization of the fundamental wave and ratating the substrate, we have found that axes (electrio-dipole) of both kinds of molecules are perpen.

The relativistic Hartree-Fock-Slater (HFSD) approximate method was used in calculating the single-eleotron energy eigenvalues and the energies of Kα, Kβ and Hβ X-rays of rare earth elements Ao, Th, Pa and U. Calculations were also carried out by taking account of the relativistio correction to the exchange potential. Our results are in good agreement with experiments (with an accuracy of 0.3%).

Based on the model of integral sampling theory, an important fact about sampled imaging systems is presented in this paper. Instead of the traditional OTF, the complex frequency analysis of the output image with a normal input of bandlimited continuous space speotrum of variable-bandwidth should be used to evaluate the sampled imaging systems acouratly and completely. An evaluation method of aliasing for sampled imaging systems and the theoretical basis of data processing are also presented.

The earthquake light has long been supposed to be a phenomenon of atmospheric discharge. But it can hardly explain the fact that the earthquake light exhibits many colors and may occur in the sea. This article suggests that the earthquake light is not caused by atmospheric discharge but is a direct radiation from the fault rocks when they arerubbing each other. This new hypothesis oan explain many phenomena that cannot be explained by original suppositions.

Based on rigorous solutions of steady multi-level rate equations, we made theoretical analysis of the behavior of CW optogalvanio signals. Acoording to the experimental results, the concept of an equivalent local electron density and its relation with the I-V curve of an HCD lamp is proposed. Experimental data of the anormalous optogalvanio spectroscopy and the sensitivity fluoresenoe of Cu irradiated by a CW laser (578.2nm) are shown for the first time. These results, together with the optogalvanic experimental data of Ne 1s—2p levels reportod else where, bear out the theory satisfactori]y.

Different points of view exist on the mechanism of neon optogalvanio effect in a hollow cathod tube. We have carried out eleotrodeless RF optogalvanio experiments to investigate such mechanism. Experimental results show that there exists no anomalous signal in the RF optogalvanio signal at the same pressure. The small peak on the tail still exsists and has no relation to the cathode. Bipolar diffusion effect is cited to discuss the peak s coourrence.

A new experimental method for on-resonant two-photon absorption speotroscopy is presented in this paper. The experimental set-up is the same as that of the two-photon fluorescence experiment used in measuring durations of ultrashort laser pulses. A picosecond laser pulse is divided into two beams which then travel in opposite directions in the sample. The signal intensity measured along the laser trace will be a wide plateau overlapped by a narrow peak. The ratio of the on-resonant two-photon absorption section to the two-step single-photon absorption section can be deduced from the contrast ratio of the peak intensity to the shoulder intensity. The theo xetical calculation shows that this method is valid for various oases.