共查询到20条相似文献,搜索用时 15 毫秒
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A. L. Sokolov 《Optics and Spectroscopy》2003,95(5):814-818
A range of questions regarding the calculation of the spatial polarization structure of laser radiation in optical systems is considered. It is shown that polarization aberrations in such systems lead to a distortion of the initial polarization structure. Requirements for an optical system intended for the transmission of the polarization structure of laser radiation and methods for the compensation of polarization aberrations are discussed. 相似文献
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For laser internal therapy in medical applications, optical fibres are required to propagate the laser beam. The far-field pattern of the laser beam at the exit face of the optical fibre is studied using a multimode step-index fibre and a graded index Selfoc fibre. The degree of dispersion, or the output angular distribution, of the beam passing through the Selfoc fibre is much smaller than that passing through the multimode step-index fibre. Consequently, the energy density in the far-field pattern of the beam passing through the Selfoc fibre is very much larger than that for the beam passing through the multimode step-index fibre. It is concluded that the Selfoc fibre is more effective in laser internal therapy. 相似文献
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Guoxuan Zhang Guosong Huang Shaoting Gu Gencai Gu Baoding Sun Zhijiang Wang 《Chinese Journal of Lasers》1992,1(3):203-212
The design and experimental results of a rotating hollow cylinder Nd:glasslaser are presented.A maximum laser energy of 13J and a repetition rate of 15Hz have beenobtained.The overall laser efficiency is 2.2%.The slope efficiency is 3.4%. 相似文献
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Yu. A. Ushenko 《Optics and Spectroscopy》2002,93(2):321-325
Transformation of the polarization structure of a laser radiation scattered by the human skin is studied. A technique based on the matrix modeling of the optical properties of the skin considered as a superposition of epidermis and dermis, is proposed. Physical mechanisms behind the transformation of the polarization state of the scattered laser radiation are analyzed in terms of the ensemble of biospeckles. 相似文献
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V. N. Listvin 《Radiophysics and Quantum Electronics》1991,34(5):510-512
Moscow Physicotechnical Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 34, No. 5, pp. 603–605, May, 1991. 相似文献
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The triplet model of electron spin polarization in fluid media is evaluated. The model consists of an initial singlet molecule rotating in a static, externally applied magnetic field. Intersystem crossing into different zero-field states is represented by a rate matrix diagonal in the molecular frame, and this matrix is expressed as an effective spin operator. The triplet rotates, and the motion affects the polarization in the laboratory frame, and also causes spin relaxation in the triplet manifold. The triplet is chemically quenched, and the polarization appears in the doublet fragments. The model is treated in a density matrix formalism and on the basis of anisotropic rotational diffusion of the triplet molecule. Explicit expressions are obtained in terms of the molecular parameters, the various rate constants, and the rotational correlation time. 相似文献
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Toshimitsu Asakura 《Optical and Quantum Electronics》1970,2(3):115-123
The ensemble-averaged spatial coherence of quasi-thermal light, produced by passing a focused laser beam through a rotating ground glass plate, is studied as a function of the illuminated area, the fineness of the glass used, the speed of rotation of the glass, and the laser mode selected as a primary source. It becomes clear that the ensemble-averaged spatial coherence depends strongly upon the illuminated area and on the fineness of the rotating ground glass, and also on the laser mode chosen but not on the speed of rotation of the glass. 相似文献
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G. Zhang F. F. Luo X. F. Liu G. P. Dong Q. Zhang G. Lin Q. L. Zhou J. R. Qiu L. L. Hu D. P. Chen 《Laser Physics》2010,20(6):1425-1427
We experimentally demonstrated a single-mode laser at 1056 nm with Nd-doped phosphate glass microstructured optical fiber
(MOF), which was fabricated with conventional stack-and-draw method. The laser action was observed from a Fabry-Perot cavity
formed by placing two dichroic mirrors of ∼100 and 85% reflectivity, to the two end facets of MOF. Pumped by CW laser diodes
(LDs) at 808 nm, the MOF laser yielded a maximum output power of 8.5 mW and a slope efficiency of 2%. 相似文献
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为了探索光辐射的时间特性, 在100 TW掺钛蓝宝石飞秒激光器上利用光学条纹相机, 分别在靶背表面法线方向测量了光辐射的时间积分和时间分辨成像光斑. 实验测量结果显示: 光辐射时间积分成像光斑呈长条状, 而辐射区域有发散角、有光强分布, 包含多种辐射成分; 光辐射的时间分辨成像光斑进一步证明, 渡越辐射(TR) 是信号强而快, 持续时间短, 为皮秒(ps) 量级, 是最先到达屏幕上, 并推算出相应的持续时间为85.5ps. 其他成分光辐射是信号弱而慢, 持续时间长, 为纳秒(ns) 量级, 是最后到达屏幕上. 光辐射的时间特性能为鉴别和判断TR信号提供了新的依据. 相似文献
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R. Meucci K. Al Naimee M. Ciszak S. De Nicola S.F. Abdalah F.T. Arecchi 《The European physical journal. Special topics》2014,223(8):1729-1742
We investigate the polarization dynamics in a quasi-isotropic CO2 laser emitting on the TEM01* mode subjected to an optical feedback. We observe a complex dynamics in which spatial mode and polarization competition are involved. The observed dynamics is well reproduced by a model that discriminates between the intrinsic asymmetry due to the kinetic coupling of molecules with different angular momenta and the anisotropy induced by the polarization feedback. We observe various dynamical regimes including chaotic dynamics and show that feedback changes these states from regular to chaotic and vice versa. Finally, the possible applications to polarization coding are discussed. 相似文献
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I. E. Vnukov B. N. Kalinin G. A. Naumenko D. V. Padalko A. P. Potylitsyn O. V. Chefonov 《JETP Letters》1998,67(10):802-807
The optical diffraction radiation of ultrarelativistic electrons at the boundary of a conducting medium is observed experimentally.
Backward diffraction radiation, which, like transition radiation, is emitted at the angle of specular reflection from the
target, is detected.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 10, 760–764 (25 May 1998) 相似文献
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CuBr自锁模激光器的实验研究 总被引:1,自引:1,他引:0
首次报道在纵向放电的CuBr激光器中,通过抑制高阶横模的振荡,同时得到高度稳定完全调制的绿光和黄光自锁模脉冲串,并在实验上研究了高阶横模,泵浦功率和谐振腔腔长对CuBr激光自锁模脉冲串及其纵模频谱的影响. 相似文献