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浏览/检索结果: 共3条，第1-3条 帮助 限定条件 内容类型：会议论文     已选(0)清除 条数/页：5101520253035404550556065707580859095100   排序方式：请选择作者升序作者降序题名升序题名降序发表日期升序发表日期降序提交时间升序提交时间降序 The investigation of point defect modes of phononic crystal for high Q resonance (EI CONFERENCE) 会议论文 2011 16th International Solid-State Sensors, Actuators and Microsystems Conference, TRANSDUCERS'11, June 5, 2011 - June 9, 2011, Beijing, China Li F.; Liu J.; Wu Y. H. 收藏  |  浏览/下载：14/0  |  提交时间：2013/03/25 Point defect cavity was constructed in a two-dimensional phononic crystal plate. It was excited by a small piezo chip in the cavity and the vibration of each point defect modes were detected by an optical interferometer. Point defect modes on 2D PC plate in vacuum  air and loaded with water were investigated theoretically and experimentally to make clear of Q factors  which are affected by inner attenuation  band gap effects and medium. The way to get high Q resonance has been found. It helps to design a new kind of resonator or sensor. 2011 IEEE.   Theoretical analysis of emission characteristics of second-order distributed feedback semiconductor lasers (EI CONFERENCE) 会议论文 Semiconductor Lasers and Applications IV, October 18, 2010 - October 19, 2010, Beijing, China Qin L.; Ye S.; Hu Y.; Zhang N.; Ning Y.; Liu Y.; Wang L. 收藏  |  浏览/下载：13/0  |  提交时间：2013/03/25 Based on the modified coupled-wave theory  the emission characteristics  including threshold gain  photon density distribution in the cavity  and external differential quantum efficiency for second-order DFB lasers are investigated. Numerical simulation results show that for given device structure with wavelength of 1.55 m  the feedback coupling coefficient and the surface radiation coupling coefficient of the second-order grating have great influence on the emission characteristics of the device. By choosing different duty cycles of the grating  we can change the two coupling coefficients  which affect the emission characteristics. For an overall consideration  an optimal duty cycle of 0.43 is chosen. The optimized results show that the device works without degeneracy modes and spatial burning hole. Besides  the side-mode suppress ratio (SMSR) and external differential quantum efficiency reach as high as 42 dB and 47%  respectively. 2010 SPIE.   The enhancement of spontaneous emission factor in selectively oxidized vertical cavity lasers with double oxide layers 会议论文 semiconductor lasers iii, beijing, peoples r china, sep 16-18, 1998 Huang YZ 收藏  |  浏览/下载：7/0  |  提交时间：2010/10/29 vertical-cavity lasers  spontaneous emission factor  laser modes  AlAs oxidation