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61.
基于自再现原理,利用菲涅耳-基尔霍夫衍射积分方程,引入腔镜失调、激光介质上的增益分布以及光阑口径,采用本征矢量法分析了大口径平凹腔薄片激光器的本征模式,并计算了相应的光束质量因子M2.建立了千瓦级薄片激光系统和光纤扫描光斑诊断装置,开展了高功率激光输出特性研究.结果表明,在大口径高功率平凹腔中多个本征模式可同时起振,获... 相似文献
62.
63.
The second largest Laplacian eigenvalue of a graph is the second largest eigenvalue of the associated Laplacian matrix. In this paper, we study extremal graphs for the extremal values of the second largest Laplacian eigenvalue and the Laplacian separator of a connected graph, respectively. All simple connected graphs with second largest Laplacian eigenvalue at most 3 are characterized. It is also shown that graphs with second largest Laplacian eigenvalue at most 3 are determined by their Laplacian spectrum. Moreover, the graphs with maximum and the second maximum Laplacian separators among all connected graphs are determined. 相似文献
64.
We simulate the polarization manipulation of bright-dark vector bisolitons at 1-μm wavelength regime.Through changing the pulse parameters,different kinds of pulse shapes and optical spectra are generated in output orthogonal polarization directions.When the input vector bisoliton is polarization-locked with 1064 nm central wavelength,“1+1”fundamental dark-dark and“2+1”pseudo-high-order bright-dark group-velocity-locked vector solitons can be achieved through changing the projection angle.When the input vector bisoliton is group-velocity-locked with 1063 nm and 1065 nm central wavelengths,“2+1”and“2+2”pseudo-high-order bright-dark group-velocity-locked vector solitons,bright-dark group-velocity-locked vector solitons with chirp-like temporal oscillations are generated.Our simulation results can provide beneficial conduct for polarization manipulation of vector multi-solitons,and have promising applications in quantum information register,optical communications,nanophotonics,and all-optical switching. 相似文献
65.
We present in situ whole-field measurements of the temperature field using laser-induced fluorescence in a study of bottom-chilled
uni-directional solidification of aqueous ammonium chloride. We utilize a two-color, two-dye, ratiometric approach to address
the significant spatial and temporal variations of laser sheet intensity field due to refractive index variations caused by
the evolving concentration and temperature fields. In our work we take advantage of two temperature sensitive fluorescent
dyes with opposite temperature sensitivities in order to increase the overall sensitivity and temperature resolution of the measurements. The
resulting temperature sensitivity (about 4% K−1) is more than a factor of two higher than the original work of Sakakibara and Adrian (Exp Fluids 26:7–15, 1999) with a sensitivity 1.7% K−1. In situ measurements of the temperature field during solidification are presented, along with temperature characteristics
of some of the complex flow features, such as plumes and fingers. 相似文献
66.
石英玻璃的非线性极化及其光学测量 总被引:1,自引:0,他引:1
本文报道了石英玻璃的非线性极化及其光学测量的全过程。研究了外电场对极化样品二阶大线性的影响。并用铁电极化模型作了一些理论分析。 相似文献
67.
68.
We report a novel scheme to optimize the focusing condition for real-time, swept-source optical coherence microscopy. The axial and lateral behaviors of four-zone binary-phase spatial filters are presented numerically. A nearly constant axial intensity distribution along an extended depth of focus of 1.5 mm and a lateral resolution of 5 microm are experimentally verified. The A-line scan rate is up to 16 kHz, yielding a frame rate of 25 Hz and 640 lines per image. 相似文献
69.
17.2 GHz, the highest fundamental-mode repetition rate to our knowledge, of a carbon nanotube-based passively mode-locked laser is realized at 1570 nm by employing purified single-walled carbon nanotubes as saturable absorbers. The ultrashort linear laser cavity configured with a approximately 9 mm length is designed and demonstrated with our extremely miniaturized nanotube mode locker and a mirror-coated semiconductor optical amplifier as gain medium. The demonstrated pulsed laser has the inferred temporal pulse width of 14 ps and a 3 dB spectral bandwidth of 0.73 nm. 相似文献
70.