高功率808nm InGaAsP—GaAs分别限制结构的半导体激光器

介绍了研究分别限制结构ＩｎＧａＡｓＰ－ＧａＡｓ半导体激光器所得到的最新成果。利用引进的俄国技术，基于量子阱结构的ＩｎＧａＡｓＰ－ＧａＡｓ激光器，可用短时间液相外延技术制造。在ＧａＡｓ衬底上制成的ＩｎＧａＡｓＰ－ＧａＡｓ分别限制结构的激光器，主要参数如下：发射波入λ＝８０８ｎｍ，阈值电流密度Ｊ＝３００Ａ／ｃｍ＾２，对于条宽ω＝１００μｍ的激光器，连续功率为１－２Ｗ。     

GaAs被动调QMd：激光器激光行性的研究

报道了用半导体材料ＧａＡｓ实现氙灯抽运Ｍｄ：ＹＡＧ激光器的被动调Ｑ运转,测量了激光器的阀值、脉冲宽度和输出能量。从ＧａＡｓ的能级结构出发,理论上研究了ＧａＡｓ材料的饱和吸收原理,建立了调Ｑ激光器速率方程并给出了数值解,对理论结果与实验结果进行了比较和讨论。     

快速光电探测器脉冲响应的电光取样测量

建立了半导体激光器电光取样系统。选择１．３μｍ，ＩｎＧａＡｓ增益开关半导体激光器作为取样光源，利用微带ＧａＡｓ衬底的纵向电光效应作为电光取样器，测量了ＩｎＧａＡｓ／ＩｎＰ雪崩二极管的脉冲响应特性。分析表明，本系统具有０．３５ｍＶ／√Ｈｚ的电压灵敏度和９ｐｓ的时间分辨率。     

垂直电子耦合InGaAs量子吉的光学特性

报导了ＩｎＧａＡｓ／ＧａＡｓ和ＩｎＧａＡｓ／ＡｌＧａＡｓ垂直耦合量子结在注入式激光器的制备工艺及其光致荧光谱，量热吸收谱和电致荧光谱的特性，该激光器的连续波波发光功率在室温下可达１Ｗ。     

生长在Ge_xSi_（1－x）（001）衬底上应变GaAs层的价电子能带结构与光学性质

采用紧束缚方法对生长在Ｇｅ_ｘＳｉ_ｌ－ｘ（００１）衬底上的应变ＧａＡｓ层的价电子能带结构和空穴的三次非线性光学极化率ｘ￣（３）进行了计算结果表明，由于应变的存在，使ＧａＡｓ层的空穴有效质量和价带态密度变小，而使偏振方向在（００１）面内的三次非线性光学极化率变大．     

SCH量子阱激光器的光学限制特性

通过对描述半导体激光器基本光波导方程的数值求解，分析了ＡｌＧａＡｓ／ＧａＡｓ分别限制量子阱激光器的光学限制特性，比较了不同缓变结构及多量子阱结构的光学限制因子。     

新型富勒烯衍生物的光限幅研究

应用倍频Ｎｄ∶ＹＡＧ脉冲激光，在波长为５３２ｎｍ、脉冲宽度分别为８ｎｓ和２３ｐｓ的条件下，研究了新型富勒氮烯乙酰氨衍生物（Ｎ－ａｃｅｔａｍｉｄｅ１，２－ｄｉｈｙｄｒｏ－１，２－ａｚａ－ｆｕｌｅｒｅｎｅ［６０］）的反饱和吸收与光限幅特性。实验结果表明，同脉宽为纳秒的激发脉冲相比，富勒烯乙酰氨衍生物对脉宽为皮秒的脉冲限幅效果比较好。     

由透射波的摇摆曲线求GaAs中Ga的反常散射因数

利用同步辐射光，在对称Ｌａｕｅ情况下，于Ｇａ的Ｋ吸收限附近，测定了ＧａＡｓ（２００）的衍射波和透射波的摇摆曲线．通过测定的透射波的摇摆曲线和Ｘ射线衍射动力学理论的相应计算结果的定量比较，求得ＧａＡｓ中的Ｇａ原子在其Ｋ吸收限附近的反常散射因数 关键词：     

生长在GexSi1-x(001)衬底上应变GaAs层的价电子能带结构与光学性质

采用紧束缚方法对生长在Ge_xSi_1-x(001)衬底上的应变ＧａＡｓ层的价电子能带结构和空穴的三次非线性光学极化率x⁽³⁾进行了计算结果表明，由于应变的存在，使ＧａＡｓ层的空穴有效质量和价带态密度变小，而使偏振方向在（００１）面内的三次非线性光学极化率x_xxxx⁽³⁾变大． 关键词：     

808nm准连续阵列半导体激光器

报道了８０８ｎｍ无铝ＩｎＧａＡｓＰ／ＧａＡｓ高功率连续阵列半导体激光器,在频率１００Ｈｚ,脉冲宽度２００μｓ,占空比达２０％时,单阵列条的输出光功率室温下达到３７Ｗ。     

半导体中相干亚毫米波的产生和传播

研究了超短光脉冲在ＧａＡｓ表面激发相干亚毫米波振幅随入射角变化的规律，前后向辐射比值随入射角度变化的规律，实验测量了ＧａＡｓ表面镀上极薄金属薄膜后产生的相干亚毫米波振幅对薄膜厚度的依赖关系，利用光生载子偶极辐射的理论模型成功地解释了实验得到的角度依赖关系和相干亚毫米波的偏振特性。     

Optical properties of Quantum Disks: Real density matrix approach

We show how to compute the optical response of a Quantum Disk (QDisk) to an electromagnetic wave as a function of the incident wave polarization, in the energetic region of interband transitions. Both the TM and TE polarization in guided-wave geometry are analyzed. The method uses the microscopic calculation of Quantum Disk eigenfunctions and the macroscopic real density matrix approach to compute the effective QDisk susceptibility, taking into account the valence band structure of the QDisk material and the Coulomb interaction between the electron and the hole. Analytical expressions for the QDisk susceptibility are obtained for a certain model electron — hole potential. Using these expressions, all optical functions can be computed. Results for the absorption coefficient are computed for InAs/GaAs QDisks. Fair agreement with experiments is obtained.     

一新型金属有机化合物在皮秒激光下的三阶非线性光学性质研究

利用皮秒激光光源,采用z扫描技术研究了一种新型金属有机化合物的三阶非线性光学性质以及光限幅特性.z扫描研究结果表明,这种化合物在1064 nm波长激光激发下的三阶非线性极化率χ(3)为3.8×１０-14 esu,并且存在双光子吸收.光限幅实验结果显示双光子吸收和非线性折射两种不同机制决定了该化合物的光限幅特性.     

GaAs在光通讯波段的超快非线性光学研究

采用Z-扫描和泵浦-探测技术,在光通讯波段对砷化镓(GaAs)单晶进行了非线性动力学以及非线性光学的实验研究.飞秒泵浦-探测实验结果表明,三阶非线性光学效应源于砷化镓单晶对飞秒激光的瞬态双光子吸收,而五阶非线性光学效应源于砷化镓单晶双光子吸收诱导的自由载流子吸收效应.通过Z扫描实验,得到了关于GaAs单晶所有的非线性光学参数,包括双光子吸收系数、三阶非线性折射系数、双光子吸收诱导的自由载流子吸收截面以及双光子吸收诱导的自由载流子折射截面.结果表明,砷化镓单晶在制造光限幅器件和光电探测器方面具有良好的发展前景.     

Optical absorption of a quantum well with an adjustable asymmetry

The effects of asymmetry and the electric field on the electronic subbands and the nonlinear intersubband optical absorption of GaAs quantum wells represented by a P?schl-Teller confining potential are studied. The potential itself can be made asymmetric through a correct choice of its parameter set and this adjustable asymmetry is important for optimizing the absorption. In that way optimal cases can be created. We calculate the modified wave functions and electronic subbands variationally. The linear and the nonlinear optical intersubband absorption coefficients are calculated. Numerical results for a typical GaAs quantum well are presented. The nonlinear part of the absorption coefficient is strongly modified by the asymmetry parameters while the electric field affects it at smaller values of the parameters. - 78.67.De Quantum wells     

半导体超晶格子带间跃迁光吸收理论研究

从理论上研究了半导体超晶格子带间跃迁的光吸收性质,以GaAs/AlxGa1－xAs超晶格为例进行数值计算,分析了该材料的吸收系数随入射光光子能量、光场强度和超晶格结构参量（阱宽,垒宽,势垒高）的变化关系计算表明：随着入射光光子能量的变化,出现非对称的吸收峰;光强只改变吸收系数大小;超晶格结构参量会改变吸收谱的谱宽和吸收峰所对应的入射光频率随着超晶格阱宽（垒宽）的增大,吸收谱由宽变窄,吸收峰红移;随着超晶格Al组分变大,吸收谱变窄.     

Optical properties in photoelectron diffraction theory

Photoelectron diffraction effects may be strongly influenced by optical properties of the solid. Due to refraction and absorption of light at a surface, the state of polarization of light may be changed and, therefore, the corresponding photoelectron diffraction intensity. In order to include optical properties of solids in photoelectron diffraction theory, a general polarization vector of light is defined taking into account both refraction and absorption of light at the vacuum–solid boundary. In a first step, the radiation field of light inside the solid is approximated macroscopically according to classical electrodynamics. Analytical expressions are derived within a real-angle representation of Fresnel equations to reveal the influence of refraction and absorption of light on the state of polarization of light. A general refractive index in dependence on the incident angle of light is introduced which determines the refractive angle inside the solid (refraction law with real angles) and the order of influence of absorption of light. The general polarization vector is applied in the calculation of dipole transition matrix elements in a multiple-scattering cluster model of photoelectron diffraction, where the process of photoabsorption (dipole transition matrix element) and multiple scattering processes of photoelectrons (scattering path operator) are considered separately. Different analytical and numerical results of photoelectron diffraction effects are presented for light of general polarization incident at general angles taking into account the optical properties of the solid. Examples are shown and discussed in detail for Cu(001) and GaAs(110) surfaces.     

Effects of Electron-Phonon Interaction on Linear and Nonlinear Optical Absorption in Cylindrical Quantum Wires

The electron-phonon interaction influences on lineax and nonfineax optical absorption in cylindrical quantum wires （CQW） with an infinite confining potential axe investigated. The optical absorption coefficients are obtained by using the compact-density-matrix approach and iterative method, and the numerical results are presented for GaAs CQW. The results show that the electron-phonon interaction makes a distinct influence on optical absorption in CQW. The electron-phonon interaction on the wave functions of electron dominates the values of absorption coefficients and the correction of the electron-phonon effect on the energies of the electron makes the absorption peaks blue shift and become wider. Moreover, the electron-phonon interaction influence on optical absorption with an infinite confining potential is different from that with a finite confining potential.     

InGaAs/GaAs量子链的光学特性研究

研究了InGaAs/GaAs量子链的稳态和瞬态光谱特性,特别是载流子的动力学过程.实验发现荧光寿命有很强的探测能量依赖关系,荧光寿命随发光能量的增加而减小;实验还发现,当激发功率较小时,荧光寿命随激发功率增大而增大,当激发功率足够大时,荧光寿命趋于饱和.这些结果清楚地表明,在量子链结构中,参与发光的载流子之间存在明显的耦合和输运现象,进一步分析表明,这种输运主要是由于载流子沿量子链方向的耦合造成的.发光的偏振特性研究进一步证实了载流子沿量子链方向输运过程. 关键词： InGaAs/GaAs 量子点 量子链     

Theoretical investigation of hot electron cooling process in GaAs/AlAs cylindrical quantum wire under the influence of an intense electromagnetic wave

Hot electrons cooling by phonons in GaAs/AlAs cylindrical quantum wire (CQW), under the influence of an intense electromagnetic wave (EMW), is studied theoretically. Analytic expression for the electron cooling power (CP) is derived from the quantum transport equation for phonons, using the Hamiltonian of interacting electron–optical phonon system. Both photon absorption and emission processes are considered. Numerical results show that the CP reaches maximum when the energy difference between electronic subbands equals the energy of an optical phonon plus the photon energy. Under the influence of the EMW, the negative CP is observed showing that electrons gain energy from phonon and photon instead of losing their energy. Also, the CP increases with increasing the EMW amplitude. Our results theoretically clarify the mechanism of the electron cooling process by phonons in the GaAs/AlAs CQW under the EMW, which is of significance for designing and fabricating high-speed nanoelectronic devices based on this material.