首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到17条相似文献,搜索用时 125 毫秒
1.
施加电场的半抛物量子阱中的二阶非线性光学极化率   总被引:3,自引:1,他引:2  
张立  谢洪鲸  陈传誉 《光子学报》2003,32(4):437-440
利用量子力学中的紧致密度矩阵方法,研究了施加电场的半抛物量子阱中的二阶非线性光学极化率(光整流系数),得到了此系统的光整流系数的解析表达式.数值计算的结果表明,随着电场强度的增加,光整流系数几乎线性随之增加,而且在同样的电场强度及抛物束缚势频率作用下,半抛物量子阱模型中的光整流系数比抛物量子阱模型中的值大一个数量级,这是由于我们所选模型本身的非对称性以及电场进一步使这种非对称性增强的缘故.  相似文献   

2.
加偏置电场的抛物量子阱中的电光效应   总被引:2,自引:2,他引:0  
郭康贤 《光子学报》1998,27(6):494-498
本文利用密度矩阵方法得到了加偏置电场的抛物量子阱中电光效应的解析表达式,并以典型的GaAs抛物量子阱为例进行了数值计算研究结果表明,电光效应随偏置电场和抛物势频率的增大而增强,同时也表明GaAs量子阱中的电光效应比体GaAs中的要强一个数量级以上。  相似文献   

3.
施加电场的半抛物量子阱中束缚态的能级结构   总被引:3,自引:0,他引:3  
张立  谢洪鲸 《大学物理》2004,23(4):21-24
采用位移谐振子与数值求解相结合的方法,研究和讨论了施加电场的半抛物量子阱中束缚态的能级结构,得到了体系的本征能量与本征函数的表达式.数值结果显示,随着电场强度的增大,束缚态的能量几乎线性地下降,电场对半抛物束缚势频率较低的系统以及系统的高能级的影响较大,相邻能级间隔也随着电场强度的增大而减小,这与施加电场的抛物量子阱中的情况明显不同.  相似文献   

4.
运用密度矩阵方法推导出了特殊非对称量子阱中电光系数的解析表达式,并以典型的GaAs/AlGaAs非对称量子阱为例进行了数字计算.计算结果表明,量子阱的非对称性随着参数a的增大而增强,随着参数V0的增大而减小.电光系数的最大值也随着参数a的增大而增大,随着参数V0的增大而减小,表明电光系数将随着量子阱非对称性的增大而增大.在取不同的参数a和不同的参数V0时,电光系数和入射光子能量的关系分别被绘制成曲线图.在图中分别有三个不同的峰,而且系统的非对称性越大,峰值就越大.随着量子阱非对称性的增大,曲线中的峰向能量低的方向移动.另外,在这种量子阱中得到了比较大的电光系数,大约在10-6m/V量级.随着近来纳米制作技术的进步,使得在实验上制作这种特殊非对称量子阱并得到较好的非线性材料成为可能.  相似文献   

5.
量子阱由于受到受限势的限制作用会体现出特殊的物理特性,在实验中发现量子阱的生长方向受限势必须是强受限势而另外两个方向为非强受限势,所以本文在量子阱的生长方向施加非对称半指数受限势构成了非对称半指数势量子阱,为了深入了解非对称半指数量子阱的结构特征,在其垂直量子阱的生长方向施加各向异性抛物势,同时又增加了磁场对量子阱中电子的限制作用,研究了磁场对该量子阱中弱耦合极化子的影响。通过两次幺正变换和线性组合算符推导出弱耦合极化子的振动频率随抛物势的x与y方向的受限强度、磁场的回旋频率及非对称半指数受限势的两个参数的变化关系。并以处在非对称半指数量子阱中的GaAs半导体晶体进行模拟计算,结果表明:当x与y方向的受限强度及磁场的回旋频率取定值时非对称半指数量子阱中弱耦合极化子的振动频率是受限势参量U_0的增函数,而它是另一个参量σ的减函数,参数的改变是电子声子间耦合加强促进了极化子的形成。当磁场回旋频率及参量U_0和σ取定值时,极化子的振动频率是各向异性抛物势的x方向和y方向的受限强度的增函数,这体现了量子的尺寸限制效应,此外,由于磁场回旋频率随磁场的增大而增大,磁场回旋频率增大时会使极化子受到更强的约束作用,所以振动频率加强。当y方向的受限强度及参量U_0和σ取定值时极化子的振动频率是磁场的回旋频率的增函数。  相似文献   

6.
利用量子力学中密度矩阵方法研究了加偏置电场的量子阱中电光效应的解析表达式,并以典型的GaAs量子阱为例进行了数值计算.研究结果表明,电光效应随偏置电场的增大和阱宽的减小而增强,通过调节阱宽和偏置电场的强度,在该系统中可以获得一个大的电光效应系数.  相似文献   

7.
O472.3 2005010713 一种特殊的非对称量子阱中的电光效应=Electro-optic effects in special asymmetric quantum wells[刊,中]/俞友宾(广州大学桂花岗校区物理系.广东,广州(510405)).郭康贤…∥发光学报.-2004,25(1).-14-18 运用密度矩阵方法推导出了特殊非对称量子阱中电光系数的解析表达式,并以典型的GaAs/AlGaAs非对称量子阱为例进行了数字计算。计算结果表明,量子阱的非对称性随着参数a的增大而增强,随着参数V0的增大而  相似文献   

8.
当非对称半指数量子阱中在阱的生长方向存在非对称半指数受限势,而在垂直于阱的生长方向存在各向异性抛物受限势时,我们理论上研究了类氢杂质対非对称半指数量子阱中弱耦合杂质极化子基态能量性质的影响.应用线性组合算符方法和两次幺正变换导出了非对称半指数量子阱中弱耦合杂质极化子的基态能量.我们挑选非对称半指数GaAs半导体量子阱晶体为例,计算了非对称半指数量子阱中弱耦合杂质极化子的基态能量与库仑杂质势的强度,非对称半指数受限势的两个正参数和x方向和y方向的各向异性抛物势的受限强度变换关系.通过数值我们发现非对称半指数量子阱中弱耦合杂质极化子的基态能量随库仑杂质势的强度的增加而增大,杂质极化子的基态能量是参量U0和x方向和y方向的各向异性抛物势的受限强度的的增函数,而它是参量σ的减函数.表现了奇特的量子尺寸限制效应.  相似文献   

9.
王文娟  王海龙  龚谦  宋志棠  汪辉  封松林 《物理学报》2013,62(23):237104-237104
在有效质量近似下采用变分法计算了InGaAsP/InP量子阱内不同In组分下的激子结合能,分析了结合能随阱宽和In组分的变化情况,并且讨论了外加电场对激子结合能的影响. 结果表明:激子结合能是阱宽的一个非单调函数,随阱宽的变化呈现先增加后减小的趋势;随着In组分增大,激子结合能达到最大值的阱宽相应变小,这与材料的带隙改变有关;在一定范围内电场的存在对激子结合能的影响很小,但电场强度较大时会破坏激子效应. 关键词: 激子 InGaAsP/InP量子阱 结合能 电场  相似文献   

10.
O472.3 2004032319 施加电场的半抛物量子阱中的电光效应=Influences of electric field on electro-optic effects in a semi-parabolicquantum well[刊,中]/张立(番禺职业技术学院电子与机械系.广东,广州(511483)),谢洪鲸∥量子光学学报.—2003,9(1).—1-6  相似文献   

11.
Within the framework of the compact density matrix approach, the third-harmonic generation (THG) in an electric-field-biased semi-parabolic quantum well (QW) has been deduced and investigated. Via variant of displacement harmonic oscillation, the exact electronic states in the semi-parabolic QW with an applied electric field have also been obtained and discussed. Numerical results on typical GaAs material reveal that, electric fields and confined potential frequency of semi-parabolic Q W have obvious influences on the energy levels of electronic states and the THG in the semi-parabolic Q W systems.  相似文献   

12.
By using the compact density matrix approach and iterative procedure, a detailed procedure for the calculation of the linear and nonlinear intersubband optical absorption coefficients is given in the electric-field-biased semi-parabolic quantum wells (QWs). The simple analytical formulas for the linear and nonlinear optical absorption coefficients in the systems are also deduced. Numerical result on typical GaAs materials shows that, the linear and nonlinear optical absorption coefficients sensitively depend on the applied electric field and the confined potential frequency of the semiparabolic QW systems as well as the incident optics beam intensity.  相似文献   

13.
By using the displacement harmonic variant method and the compact density matrix approach, the linear and nonlinear intersubband refractive index changes (RICs) in a semiparabolic quantum well (QW) with applied electric field have been investigated in detail. The simple analytical formulae for the linear and nonlinear RICs in the system were also deduced. The symmetrical parabolic QWs with applied electric fields were taken into account for comparison. Numerical calculations on typical GaAs QWs were performed. The dependence of the linear and nonlinear RICs on the incident optical intensity, the frequencies of the confined potential of the QWs and the strength of the applied electric field were discussed. Results reveal that the RICs in the semiparabolic quantum well system sensitively depend on these factors. The calculation also shows that the semiparabolic QW is a more ideal nonlinear optical system relative to the symmetric parabolic QW systems.  相似文献   

14.
We explore the profiles of electro-optic effect (EOE) of impurity doped quantum dots (QDs) in presence and absence of noise. We have invoked Gaussian white noise in the present study. The quantum dot is doped with Gaussian impurity. Noise has been administered to the system additively and multiplicatively. A perpendicular magnetic field acts as a confinement source and a static external electric field has been applied. The EOE profiles have been followed as a function of incident photon energy when several important parameters such as electric field strength, magnetic field strength, confinement energy, dopant location, relaxation time, Al concentration, dopant potential, and noise strength possess different values. In addition, the role of mode of application of noise (additive/multiplicative) on the EOE profiles has also been scrutinized. The EOE profiles are found to be adorned with interesting observations such as shift of peak position and maximization/minimization of peak intensity. However, the presence of noise and also the pathway of its application bring about rich variety in the features of EOE profiles through some noticeable manifestations. The observations indicate possibilities of harnessing the EOE susceptibility of doped QD systems in presence of noise.  相似文献   

15.
Wenfang Xie 《Physics letters. A》2009,373(26):2251-2254
Using the perturbation method, the confined hydrogen atom by a parabolic potential well is investigated. The binding energy of the confined hydrogen atom in a parabolic potential well is calculated as a function of the confined potential radius and as a function of the intensity of an applied electric field. It is shown that the binding energy of the confined hydrogen atom is highly dependent on the confined potential radius and the intensity of an applied electric field.  相似文献   

16.
张立 《发光学报》2007,28(2):231-236
考虑了由于压电与自发极化引起的强内电场效应,基于密度矩阵与久期处理方法,理论考察了纤锌矿氮化物半导体耦合量子阱体系的非线性光整流特性。根据已经成功建立的耦合量子阱的内建电场模型,精确求解了体系的电子本征态。以典型的GaN/InxGa1-xN纤锌矿氮化物耦合量子阱为例进行了数值计算,结果发现共振光整流系数达到了10-6m/V的量级(体系的偶极矩阵元大小超过了2nm),这比同样尺寸的单氮化物量子阱的相应值高一个数量级。而且,计算还发现光整流系数对耦合量子阱的结构与掺杂组分呈现非单调的依赖关系,这一特性被归结为体系的强内建电场与量子尺寸效应对载流子受限特性的强烈竞争。计算结果还表明,通过选择小尺寸阱宽与垒宽的耦合量子阱,适当降低掺杂组分,可在氮化物耦合量子阱中获得较强的光整流效应。  相似文献   

17.
The strain-induced piezoelectric polarization and the spontaneous polarization can be reduced effectively using the applied electric field in the CdZnO/ZnMgO quantum well (QW) structure with high Cd composition. That is, optical properties as a function of internal and external fields in the CdZnO/ZnMgO QW with various applied electric field result in the increased optical gain due to the fact that the QW potential profile is flattened as a result of the compensation of the internal field by the reverse field as confirmed. These results demonstrate that a high-performance optical device operation can be realized in CdZnO/MgZnO QW structures by reducing the droop phenomenon.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号