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981.
A new design of the U-type resonator is described. In this way, a laser beam with symmetrical intensity profile (regarding to a symmetry plane) can be extracted from an active medium that exhibits gain asymmetry along one of the transverse directions. The whole area of the active medium cross-section can be used, and consequently the laser efficiency will be increased. This resonator structure was applied for efficiency power extraction (as a low order TEM modes laser beam) from a DC excited transverse flow CO2 laser with cylindrical geometry. Although the cross-section area of the discharge was entirely used (including the cathode fall region), a symmetrical intensity profile of the laser beam (regarding to the two orthogonal symmetry planes) was obtained in the near field as well as in the far field; the gain asymmetry along the flow direction was compensated by the gas circulation fluidodynamical circuit with two counterflowing discharge channels. A double-U optical resonator was introduced in order to provide a laser beam with axial symmetry.For the practical construction of these two types of optical resonators we have developed two new types of 90° deflection elements: the first one, which does not reverse the image (and which has the properties of the pentaprism), and the second one, which rotates the image with 90° angle. Both elements exhibit good focusability if they are equipped with two concave mirrors. 相似文献
982.
983.
A lamp pumped high power 1341.4 nmNd:YAlO3CW laser and its performances have been described. As high as 188 W of CW output power has been obtained at 1341.4 nm alone line with a overall efficiency of 1.37% and a slope efficiency of 2.14%. The divergence (FWHM) and instability (RMS) of this laser at output power of 155 W are 15 mrad and 1.19%, respectively. 相似文献
984.
N K Porwal R M Kadam Y Babu M D Sastry M D Aggarwal Putcha Venkateswarlu 《Pramana》1997,48(4):929-935
Photo-induced charge transfer and its kinetics were investigated in Bi12SiO20 in 10–300 K temperature range, using EPR of Fe3+ centre, underin situ illumination with copper vapour laser (CVL). The decay kinetics was found to follow double exponential behaviour. Relaxation
of the photo-induced electron transfer to the preillumination condition occurred even at 10 K. Shallow traps were, therefore,
associated with the electron trapping, leading to a better understanding of the fast photorefractive response of BSO. 相似文献
985.
亚皮秒太瓦脉冲激光与物质相互作用研究进展 总被引:1,自引:0,他引:1
当前亚皮称太瓦超短冲激光技术的发展为激光与物质相互作用领域提供了许劝人心的研究机会,从激光与单个原子的相互作用到激光等离子体中的集体效应,如原子的高度离化、X射线激光、等离子体波导,等离子体粒子加速器,快速点火方案等等,文章评述了最近几年这方面的研究进展。 相似文献
986.
利用钠荧光散射激光雷达对中层顶(75~105km)高度的钠原子层进行探测,以钠原子作为示踪物,通过反演得到了该区域大气密度起伏随高度分布和随时间变化关系.结果表明,中层顶附近大气密度起伏远大于平流层和对流层,在2h内,密度起伏可达5%,3日平均Richordson数为0.46. 相似文献
987.
988.
We have studied the ratio of the intensities of radiation scattered by a layer of blood in a cuvet and by the cuvet walls
for normal incidence or incidence at the Brewster angle for probing radiation from a He-Ne laser, linearly polarized in the
plane of incidence (plane of observation) or orthogonal to that plane. We have compared it with the intensity of the radiation
reflected by the surface of the cuvet wall, as estimated based on the geometric approximation. We have found the optimal conditions
for probing and observing scattering for the layer in a cuvet, where such conditions are characterized by a minimal effect
from the cuvet walls and the maximum ratio of useful signal to background.
Report given at the Fifth International Scientific and Technical Conference on Quantum Electronics, 22–25 November 2004, Minsk,
Belarus.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 2, pp. 270–272, March–April, 2006. 相似文献
989.
Er3+掺杂ZBLAN非晶的激发态频率上转换 总被引:3,自引:1,他引:2
非晶ZBLAN光纤玻璃中掺杂稀土离子Er3+的上转换发光的研究表明,在室温、大功率半导体激光器的激发下,Er3+的荧光主要是通过单离子步进双光子过程发生的,而其多光子过程虽然非常微弱,但在强的半导体激光的照射下也可产生.通过对这两种不同过程的实验测量,可以为进一步深入地研究上转换机制提供新的依据. 相似文献
990.
用半经典理论分析了含多勒普加宽的斯塔克效应调制,使用密度矩阵近似,导出了吸收线附近NH3分子的吸收系数和调制度表达式,实验研究了10.784μm波长的斯塔克效应调制特性,调制频率1MHz时,调制度达到33%。 相似文献