According to the Wiener-Khintohine law, we have derived a general formula on the temporal coherence of gas laser with multi-longitudinal modes, and given results on the temporal coherence of gas laser under the state of symmetric and nonsymmetrio distribution, When (1) . It is consistent with the results of reference [4] and [2-3] respectively. Finally, from the theory and experiment, this paper analyses and studies temporal coherence of the above-mentioned four cases.

In this paper, the image-forming relationship of diffraction for the rainbow-holography system is discussed by the eigen-theory method of optical information theory. The expressions of the amount of information and the number of spatial degrees of freedom are given when the limiting pupil for the system is rectangular slit, the cross-like circle pupil, respectively.

Thig paper derived the formulas of caluclating the refractive index-distribution coefficients g, h4 and h6 corresponding to properties of the material used in ion-exchange process. The value of g obtained from these formulas with the measured data of the material are consistent with that measured by the imaging method.

The experimental set-up of a red picosecond pulse output from a ultrashof t cavity dye laser pumped by third harmonic from a colliding pulse mode-locked Nd:YAG laser is reported and the experimental results is presented in this paper. The dependences of the output laser wavelengths of chl a and b in different aggregations in solutions on the dye concentrations are studied. As chl a-ethanol solution with concentration of 2 × 10-3M and the length of the laser cavity less than 36 μm, a single mode-tun blea ps pulse train coula b=obtainea. Divergence angle of the laser beam ia about 60 mrad.

The semiclassioal Lamb method applied to the problem of a two-mode two-photon laser is discussed in this paper.

This paper discussed the solution of the Bloch equations of a two-level atom resonantly interacting with laser pulse trains in detail. In terms of the solution, we calculate the radiation spectrum of the two-level atom excited by the laser pulse trains and obtain the following conclusions: (1) for the atoms satisfying the condition K1/K = 1 (such as gas atoms broadened by spontaneous emission), the laser pulse trains are almost equivalent to a CW laser; (2) for the atoms K1/K《1, saying, some solid atoms lik...

In this paper, we suggest that the flight broadening should be an important factor governing line profile in a high-speed gas laser with inhomogeneously broadened line, if the characteristic flow time τj is comparable to the collision relaxation time τc. The integration -representation of profile was deduced. The width of line increases inversely proportional to t, i.e., under the proxi- mate condition of effective line width, where t=τj/τc, is the flowing parameter.

Madey pointed out that the limit of short wavelength of free electron laser with a linear accelerator is about 1μm because of available current limit. We suggest in this paper that using higher harmonic operation of a linear accelerator, a visible or ultraviolet short wavelength free electron laser is perspective.

In this paper, the SERS effect of pyridine on silver films with different thickness prepared by chemical deposition is studied. The experimental results show that geometry of metal surface plays an important role in SERS. The enhancement depends on not only the size and the separation of particles of silver surface, but also the ratio of the two. Finally, the waveguide resonance theory is used to explain the experimental phenomena. Our experimental results are in agreement with the zeroth order approximation calculation.

The effects of pH and applied potential on the enhancement of Surface Enhanced Raman Scattering (SEES) spectra of benzoic acid molecules adsorbed on the silver electrode surface have been studied. Experiments showed that bensoic acid molecules were adsorbed on the electrochemically roughened silver electrode surface via group -COO-. By changing the pH of solution, it was possible for benzoic acid molecules to be adsorbed on the electrode. The pH of solution and the applied potential affected the density of of adsorbed benzoic aoid molecules, and the applied potential affected the charge-transfer between group -COO- and silver electrode.

This paper presents the results of a joint study of automatic diagnosis of chest radiographs of pneumoconiosis. The Hybrid Optical/Digital Image Processing System of Fudan University (OPSA-1) was used. New algorithms developed for feature selection and classification led to a higher efficiency through experiments, with 94% accuracy in discriminating normal/abnormal radiographs.

Experimental measurements of the infrared spectra of CF3D are reported. Five anharmonicity constants of OF3D are obtained directly from the equations which include fundamental frequencies, overtone and combination bands.

An apparatus of CO laser magnetic resonance used for quantitative detection of NO2 molecule is described in this paper. The mathematical expression of the LMR signal has been given. The dependence of the LMR signal on the molecular concentration and laser power has been studied. The experimental results are in agreement with the theoretical analysis.

The basic fuzzy nature of colour is examined. The conventional colour specification system is analysed by using fuzzy operator. A new method for quantitatively specifying colour is also developed on the basis of fuzzy mathematics.