共查询到19条相似文献,搜索用时 250 毫秒
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与传统的旋光效应理论不同,采用三阶赝张量κ(2)jkl描述旋光现象,并将相关的电极化强度作微扰处理,直接从Maxwell方程组出发推导出了双折射晶体中自然旋光效应的耦合波方程组并得到解析解.该解析解包含了已有的旋光效应宏观理论结果,可方便地用于描述任意偏振态的单色光波在任意点群的双折射旋光晶体中沿任意方向的传播行为.最后,以石英晶体为例,通过对出射光波的偏振态分析,研究了波矢失配对旋光效应的影响.
关键词:
耦合波理论
旋光效应
非线性光学 相似文献
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利用连续波段内激光对两批光伏型碲镉汞探测器进行了激光辐照实验, 发现了两种不同的过饱和现象. 实验表明, 光伏型碲镉汞探测器在强光辐照下都会出现开路电压随光强增强而减小的过饱和现象, 明晰了PV型探测器在强光辐照下的一般规律性现象和由探测器个体差异导致的特殊现象. 从等效电路模型出发, 剖析了两种过饱和现象的发生条件, 建立了数值计算的理论模型, 对两种过饱和现象进行了数值模拟, 计算结果与实验结果符合得较好. 研究表明, 光伏型碲镉汞探测器在波段内强光辐照下引起的过饱和现象有两种产生机理, 一种是热效应引起的暗电流增大机理; 另一种是探测器材料中缺陷引起的漏电流增大机理.
关键词:
波段内连续激光
光伏型碲镉汞探测器
过饱和现象 相似文献
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利用杂质光伏效应能够使太阳电池充分利用那些能量小于禁带宽度的太阳光子,从而提高电池的转换效率.为了更好地利用杂质光伏效应提高砷化镓太阳电池的转换效率,本文利用数值方法研究在砷化镓太阳电池中掺入镍杂质以形成杂质光伏太阳电池,分析掺镍对电池的短路电流密度、开路电压以及转换效率的影响;同时,探讨电池的陷光结构对杂质光伏太阳电池器件性能的影响.结果表明:利用杂质光伏效应掺入镍杂质能够增加子带光子的吸收,使得电池转换效率提高3.32%;转换效率的提高在于杂质光伏效应使电池的红外光谱响应得到扩展;另外,拥有良好的陷光结构是取得好的杂质光伏效应的关键.由此得出:在砷化镓太阳电池中掺镍形成杂质光伏太阳电池是一种能够提高砷化镓太阳电池转换效率的新方法. 相似文献
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Tian Jiang Xiang-ai Chengi Li Li Hou-man Jiang Qi-sheng Lu 《Optics and Spectroscopy》2011,111(2):162-165
A spectral unrelated laser was induced on the short wave and medium wave photovoltaic HgCdTe infrared detectors respectively, under various power density, the detectors had a serious of output. The results show that the two detectors all had response of spectral unrelated laser, but the response was in the opposite direction. Through the analysis of experimental phenomena, it is found that carrier concentration of detectors before laser irradiation is the reason why the response of detectors was in the opposite direction. It showed valuable clue for future research on photovoltaic HgCdTe irradiated by spectral unrelated laser. 相似文献
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利用GC Valley的准连续光(Quasi-cw)近似模型,研究了短脉冲激光(纳秒ns量级)在光伏光折变材料LiNbO3晶体中写入和擦除光折变光栅的过程,给出了空间电荷场随时间变化的表达式.理论研究表明,空间电荷场的形成和擦除与两个时间参量有关,在考虑或者不考虑光生伏打效应两种情况下,这两个参量随擦除光强的变化有基本相同的变化规律,光栅的写入和擦除有相同的结果.同样,擦除一个光栅所需的光能量在两种情况下也有相同的结果.因此,在短脉冲光入射光折变晶体材料情况下,考虑光生伏打效应与不考虑光伏效应,对短脉冲光在光折变LiNbO3晶体中写入和擦除光栅基本没有影响. 相似文献
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探索LaAlO_3/SrTiO_3(LAO/STO)界面产生的新奇物理特性对理解关联电子系统中多自由度耦合和设计功能材料器件具有重要的价值.本文通过脉冲激光沉积方法在SrTiO_3基底上制备了LAO/STO薄膜,研究了正面照射LAO/STO膜面和侧面照射LAO/STO界面时的光伏效应,探讨了LAO/STO界面对光伏效应的影响.研究结果表明,在同样光照能量下侧面照射LAO/STO界面产生的光电压远高于正面照射LAO/STO膜面产生的光电压,说明LAO/STO界面对光伏效应有明显的增强作用.通过偏压调控可以进一步增强照射LAO/STO界面产生的光电压,当偏压为60 V时, LAO/STO样品的位置探测灵敏度达到了36.8 mV/mm.这些研究结果为设计场调控位置敏感探测器等新型光电子器件提供了新的思路. 相似文献
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The history and present status of the middle and long wavelength Hg1-xCdxTe infrared detectors in Poland are reviewed. Research and development efforts in Poland were concentrated mostly on uncooled
market niche.
Technology of the infrared photodetectors has been developed by several research groups. The devices are based on mercury-based
variable band gap semiconductor alloys. Modified isothermal vapour phase epitaxy (ISOVPE) has been used for many years for
research and commercial fabrication of photoconductive, photoelectromagnetic and other devices. Bulk growth and liquid phase
epitaxy was also used. At present, the fabrication of IR devices relies on low temperature epitaxial technique, namely metalorganic
vapour phase deposition (MOCVD), frequently in combination with the ISOVPE.
Photoconductive and photoelectromagnetic detectors are still in production. The devices are gradually replaced with photovoltaic
devices which offer inherent advantages of no electric or magnetic bias, no heat load and no flicker noise. Potentially, the
PV devices could offer high performance and very fast response. At present, the uncooled long wavelength devices of conventional
design suffer from two issues; namely low quantum efficiency and very low junction resistance. It makes them useless for practical
applications. The problems have been solved with advanced 3D band gap engineered architecture, multiple cell heterojunction
devices connected in series, monolithic integration of the detectors with microoptics and other improvements. Present fabrication
program includes devices which are optimized for operation at any wavelength within a wide spectral range 1–15 μm and 200–300
K temperature range. Special solutions have been applied to improve speed of response. Some devices show picoseconds range
response time. The devices have found numerous civilian and military applications.
The paper presented there appears in Infrared Photoelectronics, edited by Antoni Rogalski, Eustace L. Dereniak, Fiodor F. Sizov, Proc. SPIE Vol. 5957, 59570K (2005). 相似文献