共查询到20条相似文献,搜索用时 62 毫秒
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评述了脉冲放电激励的金属蒸气激光的发展历程和现状,根据激光发射过程,分别阐述了自终止跃迁激光和碰撞辐射复合激光的机理,报道了作者课题组最近在相关领域研究取得的新进展:包括共振-亚稳跃迁激光和复合激光的交替振荡现象,不同介质多谱线激光同时振荡现象以及碱土金属卤化物多谱线激光的实现和新发现的M-M跃迁激光。 相似文献
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Lasing in random media 总被引:2,自引:0,他引:2
Hui Cao 《Waves in Random and Complex Media》2003,13(3):R1-R39
A random laser is a non-conventional laser whose feedback mechanism is based on disorder-induced light scattering. Depending on whether the feedback supplied by scattering is intensity feedback or amplitude feedback, random lasers are classified into two categories: random lasers with incoherent feedback and random lasers with coherent feedback. A brief survey of random lasers with incoherent feedback is presented. It is followed by a review of our recent experimental work on random lasers with coherent feedback, including measurement of the lasing threshold, lasing spectra, emission pattern, dynamical response, photon statistics, speckle pattern and the investigation of relevant length scales. Large disorder leads to spatial confinement of the lasing modes, that is the foundation for the micro random laser. Some theoretical models of random lasers with coherent feedback are briefly introduced. The study of random lasers improves our understanding of the interplay between light localization and coherent amplification. 相似文献
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V. V. Gruzinskii T. N. Kopylova M. B. Levin N. V. Svinarev 《Journal of Applied Spectroscopy》1989,51(4):1035-1039
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 51, No. 4, pp. 579–584, October, 1989. 相似文献
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Lasing from a GaAs Gunn device with a Fabry–Perot (F–P) cavity and a vertical-cavity structures are demonstrated. Light output-electric
field characteristic of both F–P and vertical cavity structure Gunn device shows abrupt increase in light output above a negative
differential resistance (NDR) threshold, implying cavity gain overcoming over loss. Electroluminescence (EL) spectra from
the F–P Gunn device measured at 95 K show a significant spectral narrowing with increasing the applied voltage pulse width,
indicative of monochromatic stimulated emission due to band-to-band recombination of impact-ionized carriers. The spectra
from the vertical-cavity device are in accord with the cavity resonance as defined by the distributed Bragg reflectances (DBRs).
The theoretical model on carrier generation via impact ionization inside the propagating space charge domains shows clearly
that the built-up excess carrier density in the cavity indeed reaches the lasing threshold. 相似文献
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将石英光纤浸入低折射率的激光染料溶液中构成圆柱形微腔.采用沿光纤轴向光抽运的消逝波激励增益方式,获得了沿光纤轴向长距离的激光染料增益,受激辐射光在圆柱形微腔中回音壁模式的支持下形成激光振荡.在直径为288 μm的同一根光纤外分三段分别填入罗丹明6G、罗丹明610和罗丹明640激光染料乙二醇溶液,实现了波长分别在567~575 nm、605~614 nm和656~666 nm三个不同波段的回音壁模式激光振荡,用一根光纤同时获得了红、橙、黄三种不同颜色的激光辐射.对实验所获得的回音壁模式激光光谱做了模式标定,依据标定的模式数计算了各种模式以及抽运光在光纤截面的强度分布.计算结果表明,激光增益区域总是局限在圆柱形微腔回音壁模式的模场区域内,由此可以显著地提高抽运效率,增加抽运光沿光纤轴向的增益长度. 相似文献
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Utaro Furukane Toshiatsu Oda 《Journal of Quantitative Spectroscopy & Radiative Transfer》1985,33(6):645-651
Lasing conditions for He have been evaluated numerically. We have used a collisional radiative model to calculate overpopulation densities Δnij, which are defined as differences between population densities per unit statistical weight of the upper and lower excited levels i and j, respectively. Laser oscillations for the level pairs 21P-31S, 21P-41S, 21P-31D, 21P-41D, 31D-41F, 31P-41S, 31P-41D, and 33P-43S are possible when the electron densities are within well defined limits at low electron temperature (Te = 0.1 eV). For level pairs of the singlet state, the inversion mechanism for He is the same as for H. Only collisional processes produce population inversion in the triplet level pair 33P-43S. 相似文献
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We have described here the physical basis for lasing without population inversion (LWOPI). This type of amplification is obtained
basically by two mechanisms: (i) one is based on atomic interference and (ii) the other is based on Fano-type interference.
We have shown here, in H2 molecules, amplification without population inversion is feasible by considering both the mechanisms. 相似文献
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S. P. Palto 《Journal of Experimental and Theoretical Physics》2006,103(3):472-479
A lasing condition is formulated in matrix form for optically anisotropic thin films. Lasing behavior of liquid-crystal slabs is analyzed. In particular, it is shown that if the spatial extent of a liquid crystal slab is much larger than its thickness, then laser emission is feasible not only along the normal to the slab, but also in the entire angular sector. The generated laser light can be observed experimentally as a spot or as concentric rings on a screen. The lowest lasing threshold corresponds to in-plane sliding modes leaking into the substrate. The feedback required for lasing is provided by reflection from the interfaces, rather than edges, of the liquid-crystal slab operating as a planar Fabry-Perot cavity. For cholesteric liquid crystals, it is shown that energy loss to the sliding modes leaking into the substrates and escaping through their edges is a key factor that limits the efficiency of band-edge emission along the normal to the slab. 相似文献