The measurments of refractive index of lithium niobate integrated optical substrates were performed by means of prism coupling method on a precision goniometer with He-Ne laser. In the experiment, we used the differential technique and a liquid crystal optical rotator. The result shows that the acuracy is of 1×10-4 and the reproducible deviations are less than 5×10-5.

This paper describes the measuring of focal length of a convex lens using Moire fringes in identical direction at a distance of 2f' from the lens, which is formed by interference fringe and a Ronchi grating. This method has high accuracy and the operating is simple.

The influence of dynamic thermal effect induced by optical pumping of YAG crystal rod in a pulsed solid laser on the wave front of the output laser beam is studied in this paper. A series of time-resolved instantaneous interferograms during and after the pumping are obtained with a Mach-Zehnder interferometer, and three-dimensional time-resolved pictures of the distortion wave surfaces and the curve of thermal focal length of laser rod versus time are gained after the treatmant and calculation for interferograms, and the curve is explained.

In this paper, a principle of polarization diversity receiver for coherent optical fiber communication is briefly discussed, and the polarization-insensitive receiver on basis of polarization diversity is achieved for the first time in China. Good demodulated signals independent on polarization are obtained at 137.2 MHz and 146.0 MHz of sinusoidal-wave. This method is being applied to a 140 MBit/s FSK coherent fiber communication system at 1.5 nm.

A programmable pulse signal generator is used for controlling laser frequency, pulse width and power, when the laser pulse is controled by a computer, it can generate a series of laser pulses.

A three-layered model of Monte Carlo simulation for photon flux in skin was presented. From the results of simulation we know that by varying the distance between the inner edge of the ring detector and the beam, we can measured the blood flow at different depths. The dependence of detected photon number on the frequency shift showed an exponetial decrease. By varying the blood volume fraction (Vb) , we investigated the effect of multiple scattering on the total frequency shift and the mean frequency shift. When Vb0.01, it reflected the root-mean-square velocity.

laser acupuncture; He-Gu acupoint

Using Nd:YAG laser and optical fiber with a metal tip, 8 patients' 10 totally occluded peripheral arteries have been successfully channelized without hemorrhage and perforation occurred. The laser energy was from 360 J to 2808 J, and the length of channelized segments was from 6 cm to 45 cm. 7 patients had follow-up examination with Doppler velocimetry at one year. All of them didn' t have recurrence of symptoms.

A new method of one-step slitless rainbow holography for 2-D transparency is proposed, in which a one-dimensional diffuse screen is employed in place of the real slit and random diffuse screen. The principle of this slitless rainbow holography is analyzed by means of Fourier optics. Rainbow holograms fabricated with a one-dimensional grating in a 4f -like processing system proves to be satisfactory.

The general formula of the diffraction efficiency of volume holograms has been derived at the condition that the index of recording materials from that of the surroundings. It is found that this formula is more suitable compared with that of the Kogelnik's in practice.

The gettering experiment of laser irradiation damage on the back surface of a silicon wafer is presented. It is observed by a microscope that the defects induced by laser after high temperature annealing are thermally stable. It is examined that the oxidation induced stacking faults and the minority carrier lifetime are affected by laser damage gettering. The gettering effect is studied by neutron activation analysis.

An auto- feeding powder apparatus with good working stability and continuous adjustment of powder flow rate has been developed for laser cladding, in which the main power of the powder motion is gravity. The cladded coating is uniform and continuous. The utilization ratio of the alloy powders is as high as 94%.

Monolithic groove-coupled-cavity AlGaAs/GaAs lasers were fabricated by using the technique of reactive ion etched of laser facets. CW stable single mode operation room temperature were observed. Typical single mode (FWHM) is about 0.23 nm mode suppression, 19 dB, mode space, 2.5 nm, and two-cavity threshold current of mode operation, 52 mA.

Influence of Ne pressure, input voltage, wall temperature and discharge tube atmosphere on optimal delay of the CVL oscillator- amplifier chain is studied. Experiments show that influence of laser operating parameters on the yellow light optimal delay is larger than that of green light. When laser operating parameters change, the optimal delay has larger variation relative to maximum amplification region (10 ns).

In this paper, degenerate four- wave mixing in borosilicate glasses doped with crystallites of the mixed semiconductor CdSxSe1-x is reported. When the experiments were performed with the light pulse at wavelength A=0.532 μm, pulse-durations tp=8 ns and tp=6 ps, these semiconductor-doped glasses exhibit third-order nonlinearities x(3) of -10-9～10-8esu and -10-11 esu for DFWM with 10 ns and 6 ps laser pulses, respectively. The experimentally measured decay time of the gratings is 30 ps, with a time resolution of 6 ps.

In this paper, phase-matched second harmonic generations in a novel organic material-MHBA have been obtained. The high conversion efficiency of 58. 94% for 1.06 μm→0.532 μm (Q-switched Nd:YAG laser), was firstly realized in organic crystal. Moreover, we have observed strong blue-violet light output, the tunable wavelength of which was 400～450 nm. Conversion efficiency of about 6% for 0.83 μm→0.415 μm has been obtained.

In solid/liquid systems, the enhancement factors of electromagnetic and non-electromagnetic is intensively studied by measuring the characteristic peaks at 1004 cm-1 and 1010 cm-1 appearing in SERS spectra of pyridine on Ag surface. The concentration corresponding to the saturated adsorption of pyridine on Ag surface is also discussed.

A RF excited CO slab waveguide laser is described. There are two ways to increase the laser output power. A maximum output of 120 watts with an efficiency of 17% has been achieved from a sealed 2 mm×20 mm×386 mm volume discharge at the electrode temperature down from 20 ℃ to -30 ℃.

A theoretical analysis is made of the characteristics of the thermal regime in a coaxial low-pressure CO2 laser and the output capability of the laser is compared with that of the conventional tubular lasers.

The expression of phase matched angle θm(λ) for MgO:LiNbO3 crystal has been obtained in this paper by using the least-square fitting method.