An experimental study of backward coupling Raman cleanup, pumping by ruby laser, is presented in high pressure H2. In the experiment, the maximun amplified factor of the seed beam (near diffraction limit) is 64, the maximun energy conversion coefficient is 32%. And the dependence of coupling amplified coefficiention seed beam, pump energy and the pressure of H2 is discussed.
The research of the selection on intervals of multi-pair electrodes and pulsed discharge time was described.
It is found from the family of standard Voigt profiles that the curves of η≤1.2 are very close to the curve of η=0 (homogeneously broadened). Combining with the experimental facts, the concept of making the gain medium predominantly homogeneously broadened is clarified and the conditions of single-longitudinal-mode operation without special optical mode-selection for homogeneously broadened lasers are deduced in details.
The upside-down taper lens fiber end is produced by the special technique. This new type optical fiber end can be used to make varied optical devices. By using single-colour coherent light source and the second-order statistical correlation function, the optical field statistical correlation properties and the optical intensity distribution formed by the upside-down taper lens fiber end are calculated. The similar results of the general cut fiber end are given for comparison with the upside-down taper lens fiber end. The theroetical results are tested and verified using He-Ne laser as the single-colour coherent light source in experiment.
Laser damage thresholds, morphologies, and multiple pulse damage produced by XeCl excimer laser at 308nm on thin film optical coatings are reported. Effect of the pre-irradiation of the sample on damage threshold is investigated.
In this paper, a self-designed scanning tunneling microscopy (STM) with large scanning for the measurement of optical disk pregrooves is reported. The gray image, three-dimension topography and cross- section profile of pregrooves are given. A new effective appraoch is proposed for evaluating pregrooves.
In this paper, the theory of Fourier optics and diffracted scattering are used to analysis the effect of diffracted scattering of particles A12O3 in real rocket exhausted jet on the moire deflectogram. The phenomenon of moire fringes confusion caused by the diffracted scattering of particles A12O3 is studied experimentally. The results show that for the solid propellant of containg Al powder of 3-8%, the flow field of its rocket exhausted jet can be visualized with moire deflectometry.
The optical transmission spectra in He-Ne laser irradiated undoped GaAs film have been determined experimentally.
Different wavelength lasers (308 nm, 193 nm and 2.94 μm) were used to irradiate cornea. Morphological changes of epithelial and endothelial cells were observed by quantitative image analysis. It was found that epithelial cells of cornea irradiated by 308 nm excimer laser have apparent changes in nuclear area and morphology. The epithelial cells regenerated after 193 nm laser irradiation have no obvious change. After 2.94 μm laser irradiation, no change in nuclear morphology and area was observed. But it was harmful to endothelial cells, if energy density or ablating depth was excessive.
Using nitrogen laser at the wavelength of 337.1 nm as an excitation source, the fluorescence lifetimes of normal intimae, atherosclerotic plaques and thrombo-emboli were measured. Results indicated that time-resolved fluorescence can be utilized for diagnosis of the lesions in the artery vessels.
For increasing the production of Getamicins, a He-Ne laser was used to mutate the protoplast of Micromonospora echinospora. The strain a was obtained through experiments which could produce more Getamicins than the original one.
A kind of two-step circular viewing rainbow holography with orthoscopic images is presented. A 360° circular viewing rainbow hologram recorded on a plane plate can be obtained by utilization of aperture conjugation technology two times. Here, the strict conjugation reconstruction and aiming process to replace the image are not necessary. Also, there is no requirement of particular or large aperture optical elements.
In this paper, a laser scanning deposition method for large area superconducting films is presented. Using a optical transmission system to make the laser beam to scan on the superconducting target with different radii rotation and to ablate it for depositing large area superconducting films. The results show that film thickness uniform areas enlarge about 10 times using this method.
A magnetic-optic hybrid current sensor is presented. The measurement result shows that the linearth of ±0.5% and repeatirity of ±0.46% can be acheived in a rang of 1~8 kA.
It is reported that, using 250W CW Nd:YAG welding machine, we weld the small holes on the valve chamfers for internal combustion engines. The Influence of welding powders, powder putting-on method and laser action time on the rate for successful welding is investigated. Experimental results show that this welding technique is successful, and the rate for successful welding is over 75%. It is estimated that using this welding method will produce high economy efficency in making valve chamfers for internal combustion engines.
The propagation pattern of the EH11 mode of waveguide HCN laser in free space is discussed and compared with the theory. In the near field, the intensity distribution is affected by the structural asymmetry of the laser, with some characteristics consistent with that calculated by Degnan; in the far field, the propagation of EH11 mode is approximated to the propagation of a Gaussian beam. Hence, the measurement of the laser propagation characteristics in the far field is the basis for the optical design of optical systems.
Adopting a copper vapor laser system consisting of a self-filtering unstable resonator and an inject ion-locked amplifier, the output power of 9.2 W on 510.6 nm line with polarization degree of 93% and about six times as large as diffraction- limited divergency was obtained. Focusing the laser beam into a 9 mm long BBO crystal, the second harmonic of 1.2 W was generated with conversion efficiency of 13%. When the filtering aperture was removed, the conversion efficiency fell down to 8%.
A single light beam method for measuring the nonlinear optical index of C60/C70 in toluence solution at picosecond range is reported. The concentration of C60/C70 is 3.5×10-3 mol, and the content of C60 to that of C70 is 3:1. The pump beam with 40ps width was generated by an passive mode-locking Nd:YAG laser. The nonlinear refractive index of C60/C70 solution is n2=(2.3±0.3)×10-11 esu, the average hyper-susceptibility γ=1.1×10-31 esu.
In this paper, the optical metric model was introduced, by which the motion of light in linear media was studied and the comparision with the traditional results are presented.