NORMAL-INCIDENCE QUANTUM WELL INFRARED PHOTODETECTOR WITHOUT GRATING COUPLER

The n-type GaAs/Al_xGa_1-xAs multiple quantum well infrared photodetectors have been demonstrated without any grating couplers. We have achieved a responsivity R_v of 1.7×10⁵V/W and a detectivity D_λ^* of 4.0×10¹⁰ cm (Hz)^1/2/W for a wavelength of 8.4 μm at a temperature T = 77 K in normal incidence.     

电泳法(EPD)制备YBCO超导涂层的微结构及其性质

采用顶部籽晶技术和熔融织构工艺改善晶界弱连接 ,并研究不同尺寸的籽晶对超导涂层微结构和超导性质的影响 ;用与基片同样尺寸的籽晶制备 YBCO超导涂层 ,再经过高压氧处理过程 ,YBCO超导涂层的临界电流密度有很大提高     

Reversal transient laser-induced voltages in La2/3Ca1/3MnO3 films

This paper reports that the transient laser-induced voltages have been observed in La2/3Ca1/3MnO3 thin films on MgO （001） in the absence of an applied current. A peak voltage of - 0.15 V was detected in response to 0.015J pulse of 308 nm laser. It is demonstrated that the signal polarity is reversed when the films are irradiated through the substrate rather than at the air/film interface. Off-diagonal thermoelectricity may support the inversion of the signal when the irradiation direction is reversed.     

Co:BaTiO3/Si(100)纳米复合薄膜制备、微结构及其紫外光电子能谱研究

采用脉冲激光气相沉积(PLD)方法，在Si(100)晶面上制备了Co:BaTiO₃纳米复合薄膜.采用X射线衍射(XRD)结合透射电镜(TEM)方法研究了两种厚度Co:BaTiO₃纳米复合薄膜的晶体结构，当薄膜厚度约为30 nm时，薄膜为单一择优取向；当薄膜厚度约为100nm时，薄膜呈多晶结构.原子力显微镜(AFM)分析表明，当膜厚为30nm时，薄膜呈现明显的方形晶粒.采用紫外光电子能谱(UPS)研究了Co的价态和Co:BaTiO₃纳米复合薄     

向染料激光说再见

最近,美国光谱物理公司(Spectra-Physics)研制成功一种蓝宝石-掺钛(Ti:sapphire)可调谐连续固休激光器.它的优异性能和宽广的调谐范围可以取代四种低性能的红外染料激光器.图1给出蓝宝石-掺钛激光与四种红外染料激光的调谐范围与输出功率的比较曲线.这种新型的固体激光光源使红外染料激光显得大为逊色.蓝宝石-掺钛固体激光器的突出特点是:输出功率比任何一种染料激光器的输出功率高三倍以上,而且还可以更高;在700—1000um的宽广调谐范围内,其功率输出几乎是相等的;此外它更具有染料激光所不能比拟的长寿命、使用方便以及多用性等突出优点.…     

超晶格Fano共振的Raman散射研究

超晶格Ｆａｎｏ共振的Ｒａｍａｎ散射研究赵铁男，朱恪，陈正豪，金奎绢，潘少华（中国科学院物理研究所北京１０００８０）林筠（中国地质大学北京１０００８１）ＲａｍａｎＳｐｅｃｔｒｏｓｃｏｐｉｃＳｔｕｍｅｓｏｎＦａｎｏｒｅｓｏｎａｎｃｅｏｆＳｕｐｅｒＡｔｔｉ...     

1983年国际激光会议(广州)简介

1983年国际激光会议(83’International Confere-nce on Lasers,简称83’ICL) 于9月6日至9月9日在广州召开. 参加本届会议的代表共352人(包括中国代表240人).会议中共宣读论文234篇(国内105篇,国外97篇,国内外合作32篇),张贴论文78篇.这些论文都是经过各地区(美洲、西欧、东欧、日本、中国和其它地区)节目委员会的严格评审选出的. 会议论文按内容可分为非线性光学、激光光谱、激光化学、激光与等离子体相互作用、激光理论、激光器件、激光材料与元件、激光应用、工程技术等九个专题. 一、非线性光学、激光光谱学 和激光化学 本届会议反映…     

Large third—order optical nonlinearity in Au nanomeytre particle doped BaTiO3 composite films near the resonant frequency

Nanometre-sized gold particles embedded in BaTiO₃ composite thin films (Au/BaTiO₃) were fabricated by the pulsed laser deposition technique. The films were grown on MgO (100) substrates at 700℃. The crystalline property of the films was studied with x-ray diffraction. X-ray photoelectron spectroscopy was used to check the Au composition and chemical nature for the deposited films. The absorption peak due to the surface plasmon resonance of Au particles was observed at the wavelength of about 570 nm, which increased as the metal particle size was increased. The nonlinear optical properties of the Au/BaTiO₃ films were determined using the z-scan method at the wavelength of 532 nm, which was close to the resonant frequency. The real and imaginary parts of the third-order nonlinear susceptibility χ⁽³⁾ at an Au concentration of about 6.7 at.% were determined to be 6.62×10^-7 esu and -6.24×10^-8 esu, respectively. The films showed a very large absorption, masking the nonlinear refraction effect at high metal concentrations.     

折迭式双波长可调谐单模TEACO_2激光器

研制了一台折迭式双束可调谐TEA CO_2激光器,该器件可以同步地产生两束波长在9.2μm～10.9μm之间独立可调的激光.单线单模输出最大峰值功率为1MW,单线多模输出最大峰值功率为4MW.文中对器件的模式选择和双波长输出的同步特性等作了分析并给出了实验结果.     

La0.8Sr0.2MnO3薄膜光生伏特效应的微结构起源

研究了外延La0.8Sr0.2MnO3薄膜的光生伏特效应。实验发现，当脉冲激光从基底一侧照射时，光生电压改变符号。电子衍射微结构分析表明，La0.8Sr0.2MnO3薄膜是外延生长的基底上的，样品显示出正交取向畴的形式。薄膜表面光生电压的分布研究表明，这种异常的光生伏特效应是由于薄膜中取向微结构畴的非对称性所致，当紫外激光照射薄膜时，在La0.8Sr0.2MnO3中感生出电子空穴时，而薄膜中非对称的微结构畴会产生内建电场，引导激发的非平衡载流子运动，最终诱导出光生电压。