The Fourier analysis has been used to examine the exit amplitudes of the Lyot-type birefringent filter. It has been found that all of its Fourier coefficients are equal to (1/2)y N is the number of the elements. Therefore the equal Fourier coefficient birefringent filter has been invented. The new filter described in this paper consists of a number of birefringent crystal plates with equal thickness between two polarizers. Selecting the angles between plates, we can make the Fourier coefficients of the filter to be equal to l/(w + l),m is the number of the plates. When two polarizers are parallel and the angles increase gradually, the Fourier coefficients are not only equal in value, but also in sign. When the wave numbers of the retardation aro integral, the maxima transmission are available. When two polarizers are perpendicular and the angles change alternately sign, the Fourier coefficients are only equal in value, but signs change alternately. When the wave number of retardation are half integral, the transmission maxima are available. If (m-f-1) instead of 2N in the formula about Lyot-type filter is replaced by (in + 1), we can obtain the various similar characters of the new filter. For example, the band width AX~ z]Ai'2,/(m + l), the thickness of following element d2 = (m + 1) dx. Multiplying Fourier expressions of two equal Fourier coefficient filters with matched thickness, we can obtain the Fourier expression of the composition filter. According to our theory, we have found eleven kinds of strict combinations between the equal Fourier coefficient filter and, respectively, the equal Fourier coefficient filter, the Lyot filter, the Evans filter, Sole filter and the partial polarizer filter. From these combinations we can obtain various kinds of filters. The above properties have been justified by computation. Before then, because there was no theory of strict combination between Sole and other filters, the increased scattering light is inevitable. We have designed a program for calculating the angles between plates for m 100, and the angles for m 15 have been computed. The most important designing data then have been provided. At last, we give the formulae about for estimating the angle and thickness errors of the filter.

This paper reports the experimental results of the second harmonic structure observed in linear polarized Nd:glass laser irradiated plane and foil aluminium targets, such as frequency shift, line broadening, spectral structure as well as self-focusod filaments, and gives a theoretical explanation to these phenomena.

In this paper, the general case of gas laser cavities is shown when the diffusion of molecules is so fast that the spatial holes burned are almost washed out, and the light intensity superposition can be used in the stimulated emission terms and stimulated absorption terms. Thus the physical foundation of the light intensity superposition is laid by virtue of the concrete analysis of a 003~N3~H20 system, it is pointed out that except some particular cases, the light intensity superposition can always be used to calculate the field distributions and power outputs for general CW gas laser.

Common tunable CW 002 lasers only have limited output power with unstable branch and intensity due to the environment variations which will cause the branch jumping and the intensity fluctuation predominantly. But the branch and intensity stabilities are rather important for many applications as same as high power output. In a previous paper1113, we have reported that the output more than SOW with a folded compound cavity was obtained. In the present paper, we report the influences of the folded compound cavity on both the branch and intensity stabilities. With this cavity, the folded compound cavity configuration will show some frequency characteristics and compensation effect for the variation of the environmental condition, and hence long-term stability of the branch and the intensity output are obtained. We have observed that the output power fluctuation was less than 5% with branch stabilized for a relaxed environment conditions as the fluctuations of discharge current in the plasma tube within 2mA, the temperature of cooling water within 1.5 ℃ and the room temperature within 3 ℃. We find that there will be an inherent automatism effect for stability controlling of the branch by suitable initial setting of the cavity, and this novel phenomenon is discussed and explained also.

LgSK528/767 (vy,F = 14.6) and FK486/817 (vg,F = 19.0) are taken as the compositions of the base glasses in our work. The effects of about 30 compounds such as fluorides, phosphates, etc. on the partial dispersions have been studied and the quantitive results have been obtained. Finally according to Sellmeir s dispersive theory, the relationship between the partial dispersions and compositions of the base glasses in our work. The effects of about 30 compounds such as fluorides, phosphates, etc. on the partial dispersions have been studied and the quantitive results have been obtained. Finally according to Sellmeir's dispersive theory, the relationship between the partial dispersions and components of the optical fiuorophosphate glasses has been discussed with dispersive equations, and satisfactory results have been obtained. The partial dispersive coefficients given by Gan Fuxi were substituted into the formula for computing the resultant partial dispersions of the glasses. We found that the computed results corresponds to our experimental data. The results proved that the computing system is valuable and can provide theoretical basis for developing new types of glasses with anomalous partial dispersions.

This paper is a report 011 the observations of saturated optical absorption in chalcogenide glass bulks or films of the As -S-Soz-Tex^ quartenary system under Nd:glass laser irradiation. When sample is placed outside the laser cavity, the nonlinear effect of the light transmission varying with the laser power is observed, and the light transmission of the sample increases by about 30%. When sample is placed inside the laser cavity, the modulated effect is observed. It is considered that the saturated optical absorption in the chalcogenide glasses of As-S -Sef-Te1x system is caused by self-induced dynamic Burslein-Moss shift of the fundamental absorption edge.

It has been a long history of studing the vibrational spectra of inorganic glasses and a great deal of information has been accumulated by infrared absorption spectroscopy. With the emergence of laser as an intense monochromatic coherent excitation light source, laser Raman spectroscopy has become one of the effective methods to study vibrational spectra of glasses. Previously, the vibrational spectra investigation of glasses was concentrated on the theoretical calculation based on the tetrahedral model of simple oxide and analysis of vitreous structure by comparing the theoretical vibrational spectra with experimental ones. Such method has encountered lots of difficulties in case of rather complicated glass composition. Therefore, by means of X-ray diffraction analysis, vibrational spectra of crystalline and theory of the structural chemistry, some glass structure information can be obtained from vibrational spectra of glasses. The systematic investigation on vibrational spectra of binary silicate and binary borate glasses have been made. However, little work has been done for other glass systems or multicomponent glasses. In this paper, IE, and Raman spectra of multicomponent inorganic glasses have been investigated. Using IR and Raman spectroscopy, we studied the multicomponent glass systems, including silicate, borate, phosphate, germanate, tellurite and fluoroberyllate. Their vibrational spectra are reported, the possible bond vibrations corresponding to these peaks are also given. The relative Raman cross section of the main peaks of the glasses were calculated. Nonlinear susceptibility of the glasses were also calculated by the method suggested by Gan Fuxi. It can be found there appears some relation between relative Raman cross section and third-order susceptibility of glasses.

The dislocation of distribution and density in six crystal rods were determined by birefringence topography and chemical etching. Their optical quality were also inspected by optical method. Laser measurement of output performances of these crystal were conducted in a Q,-switched YAG laser device. The experiment result is shown that the dislocations can form stress field causing strong birefringence when the dislocation density increases to considerable extent. As a result, light wavefront passing through the crystal is distorted and the interference fringes areincreased. As well as extinction ratio in region of high dislocation density is also decreased. Therefore, the dislocation structural defect will also be origin of optical inhomogeneity in crystals. By experimental results of laser performance of these crystal, it is pointed out that there are great influence of dislocation on laser output characteristics. From laser near-field patterns, the laser oscillation can not take place in the region of high dislocation density due to high laser threshold and the light is depolarized by birefringence effect. Because of high dislocation density, the laser divergence is increased and the frequency doubling efficiency is also decreased. The laser output performances changed more obviously when existing decorated dislocations in these crystals.

Optically pumped FIR lasers give only discrete spectrums. This property restricts the practical use of lasers. Since 1977, many research works have been done to tune the output frequency of FIR laser, of which some are tried to find the possibility of tuning the laser lines by changing the pumping frequency continuously. But it is not easy to get an accurate result due to the complexity of theoretical calculation especially for quantum system of more than three energy levels. In this research work, two photon processes in four levels system have been studied by means of graph theory, which was developed by T. A. DeTemple et al. It was found that the output frequency of optically pumped FIR laser could be tuned with a frequency range equal to the frequency difference of two FIR transition frequencies. The tuning curves of FIR frequency and the curves of system gain coefficient vs. pump detuning frequencies were given.

In this paper, calculation formula for derivative secondary spectrum is derived based on the wave aberration theory, using the change of coordinates for incidence ray on the back group from the front group which has some chromatic aberration. When applying this formula to separated thin lens system, a brief conclusion is obtained. Besides, the concept of equivalent glass is used and extended to develop a design method for correcting the secondary spectrum by means of closed thin groups with normal glasse.

It is found that there exists a notable axial pressure difference of 1 to 2 torr during the operation of the He-Cd laser, which is about a half of the He operation pressure or 3 times of the pressure difference in pure He electric discharge. The effects of pressure difference on laser output, noise and stability are investigated. After using a diffusion return path, the laser output power at 4416 A. is increased from 80mW to 110 ml, the noise is decreased to 1.3% at 44161 and to 0.9% at 3250A, and the stability of laser output is greatly improved. The rate of Langmuir flow moving along the direction from the cathode to the anode is calculated to be I5cm3/sec. The experiment results are discussed. The decrease of pressure difference may reduce the sputtering of cathode, and thus prolongs the lifetime of laser.

A new method is presented for producing tunable ns duration pulse train from a fiashlamp pumped dye laser using gain saturation and frequency locking effect. This method employs two coupled cavities. A tunable seeded pulse, which is produced in a short cavity contained tuning elements, is injected into another long cavity without tuning elements. Then the pulse modulation is formed and continued relying on gain saturation. The spectrum of the output pulses is locking at the frequency of the seeded pulse relying on the frequenoy locking effect. This method gives a higher tuning efficiency. The number of the output pulses can be controlled without pulse selective arrangements, with the Rh6G in ethyl alchol the pulse trains of 3 ns duration pulses with less than 0.01 nm spectral width were obtained.

In the shearing interferometer with a single plate, the wedge of the plate is regarded in general as one of the sources of the measure errors. A new effect in the shearing interferometer with a single plate-the self-set off effect is described in this paper. Thus, the wedge of a plate isn t not only the error sources in measuring the wave front, but also at the same time obtains the radius of curvature of the wave front together with the wedge of the plate from the readings of the interference fringes counted in two different conditins.

We have experimentally investigated variations in ellipsometrical parameters ψ, Δ, ρ, reflectivity R,surface sheet resistance p with radiation time by GW OOa laser annealing. Output power of 002 laser is 40 watts and beam diameter <~8 mm. 150 keY As+ ions were implanted to a dose of 1×10 16/cm2 for 6~8 Ω*cm(100)P type Si. The experiments discovered that t|r, A, R, 0 didn't obviously change in initial stage, but sharp decreased to the vicinity of values of the crystal silicon at 5 seconds radiation, and there were no any changes when extending radiation time. Measurements of thermoelectric couple and optical pyrometer shown surface temperature of Si has already reached about 1000 K in condition of 5 seconds radiation. The ifj, Zl-radiation time relation is similar to \ft, Zlof curves, it explains that OW OOa laser annealing has the characteristic of thermal annealing. We can understand from an abrupt turn in A, R, p curves that laser annealing of ion-implanted layer is swiftly completed during 1~2 seconds, and is not any linear or gradual process.

There is little experimental information about Na2 b3?+g+-Na2 x3?+u emission, which may be used in tunable optical converter in the near infrared region from 770.0 nm ~ 900.0 nm. This transition has recently been a subject of considerable interest. Attempts to observe such an emission have not been successful. Na2 (ba?+g) state can not be excited directly, nor can be excited by energy exchange collisions. One possible way is with indirect radiative pumping.