共查询到20条相似文献,搜索用时 125 毫秒
1.
将二维金属光栅结构引入到探测器结构中,以提高太赫兹(THz)量子阱光电探测器的探测率。采用三维时域有限差分算法,建立了THz量子阱光电探测器的二维金属光栅仿真模型,详细分析了二维金属光栅参数对太赫兹量子阱光电探测器的电场强度的影响。仿真分析结果表明:当入射光频率为6.27 THz(相对应波长为47.847 m)、光栅周期P=10.5 m、占空比=0.55(金属块宽度w= 5.755 m)、光栅层厚度h=0.4 m时,器件中的Z方向上的电场值最大,光栅的耦合效率最高。 相似文献
2.
太赫兹技术由于具有重大的科学价值及应用前景而引起了广泛关注,其核心问题是性能优异的室温太赫兹辐射源和探测器研究.本文用半经典的玻尔兹曼方程方法研究了In As/Ga Sb量子阱系统中载流子对电磁场的响应,运用平衡方程方法求解玻尔兹曼方程得到了量子阱系统中的光电导,系统地研究了量子阱结构对光电导的影响,揭示了在该量子阱系统中光电导产生的物理机制.研究发现,量子阱结构主要通过调节载流子的能级、浓度和波函数的耦合影响光电导,对称性较好的量子阱结构(8 nm-8 nm)的光电导信号更强,其峰值落在太赫兹区(0.2 THz),并且在低温下器件的性能较好,温度升高则吸收峰略有降低,且光电导峰值发生红移.研究结果表明该量子阱系统可以用作室温太赫兹光电器件. 相似文献
3.
4.
光伏型太赫兹量子阱探测器(PV-THzQWIP)是光伏型量子阱光电探测器(PV-QWIP)在THz波段的扩展,它具有功耗低、暗电流小、噪声水平低以及焦平面阵列(FPAs)热分辨率高等优点,是THz频段技术应用的重要器件之一.文章主要介绍了PV-THzQWIP的工作原理、特点、理论设计及其研究进展. 相似文献
5.
采用一个光谱匹配的太赫兹(THz)量子阱探测器(QWP)研究了一激射频率约为41 THz的THz量子级联激光器(QCL)在不同驱动电流下的发射谱,分析了测量得到的发射谱谱型和谱峰位置,根据测量的发射谱估算了太赫兹量子级联激光器发射功率随驱动电流变化的情况,从而得到了THz QCL激射的电流密度范围及其阈值电流密度.文中还研究了THz QWP在不同温度下对THz QCL 激光辐射的响应特性.研究结果表明,THz QWP在表征THz QCL的发射谱方面是一种很好的探测器,并有望成为未来THz通信中的接收装置.
关键词:
太赫兹量子阱探测器
太赫兹量子级联激光器
太赫兹通信
Fourier变换红外光谱 相似文献
6.
7.
8.
本文从有效质量近似理论出发,在量子阱导带内子带间光吸收分析的基础上,评述了n型量子阱红外探测器的光耦合。着重研究适宜于量子阱红外探测器的不同种类的光栅,并从理论上优化出高耦合效率的各种光栅参数 相似文献
9.
近年来,随着太赫兹科学技术的兴起,Ga N基量子级联激光器成为进一步提高太赫兹源工作温度潜力的研究方向之一。半导体量子点由于其优越的量子限制效应对改善光电器件的特性有重要的作用。本文系统研究了引入Ga N量子点后,Ga N量子点层厚度对双阱结构周期的AlxGa1-xN/AlyGa1-yN太赫兹量子点级联激光器的有源区结构优化设计的影响,并考虑了各种不同掩埋量子点的阱层厚度的影响。发现该结构中量子点层厚度越小,跃迁发光能级的能量间隔越小,且处于太赫兹光能量范围内;反之量子点层厚度越大,明显超出了太赫兹范围,尤其超过2 nm后压电极化效应使量子点左侧的阱中的三角形势垒抬高,更加不利于发光跃迁的进行。因此量子点级联激光器要产生太赫兹波段的辐射需要量子点层厚度足够小,对该结构来说应小于等于1 nm。此外还发现总体上跃迁发光的能级间隔几乎不受掩埋量子点的阱层厚度的影响。这些研究结果可为引入Ga N量子点的AlxGa1-xN/AlyGa... 相似文献
10.
超薄金属膜在太赫兹波段的探测器、反射镜、波导器件以及太赫兹量子级联激光器中得到了广泛应用。超薄金属膜的光学常数不仅是这些器件设计中不可缺少的参数,而且是开发新型光电材料的一个重要依据。文章运用太赫兹差分时域光谱技术对超薄金属铬、镍和钛膜的光学特性研究,获得其在太赫兹波段的折射率和消光系数,并根据菲涅尔公式计算入射介质为高阻GaAs时,GaAs/Metal界面的反射谱,三种金属在0.3~1.5THz的波段范围内的平均反射率均超过80%。研究超薄金属膜在太赫兹波段的反射特性,为设计性能优良的太赫兹辐射源、探测器及太赫兹光学元件奠定基础。 相似文献
11.
Non-perturbative multiphoton excitation studies in an excitonic coupled quantum well system using high-intensity THz laser fields 下载免费PDF全文
《中国物理 B》2019,(8)
Multiphoton excitations and nonlinear optical properties of exciton states in GaAs/Al_xGa_(1-x)As coupled quantum well structure have been theoretically investigated under the influence of a time-varying high-intensity terahertz(THz) laser field. Non-perturbative Floquet theory is employed to solve the time-dependent equation of motion for the laser-driven excitonic quantum well system. The response to the field parameters, such as intensity and frequency of the laser electric field on the state populations, can be used in various optical semiconductor device applications, such as photodetectors,sensors, all-optical switches, and terahertz emitters. 相似文献
12.
Zhaolu Diao Christopher Bonzon Giacomo Scalari Mattias Beck Jrme Faist Romuald Houdr 《Laser \u0026amp; Photonics Reviews》2013,7(5):L45-L50
Compact semiconductor light sources with high performance continuous‐wave (CW) and single mode operation are highly demanded for many applications in the terahertz (THz) frequency range. Distributed feedback (DFB) and photonic crystal (PhC) quantum cascade (QC) lasers are amongst the leading candidates in this field. Absorbing boundary condition is a commonly used method to control the optical performance of a laser in double‐metal confinement. However, this approach increases the total loss in the device and results in a large threshold current density, limiting the CW maximum output power and operating temperature. In this letter, a robust surface emitting continuous‐wave terahertz QC laser is realized in a two‐dimensional PhC structure by a second order Bragg grating extractor that simultaneously provides the boundary condition necessary for mode selection. This results in a 3.12 THz single mode CW operation with a 3 mW output power and a maximum operation temperature (Tmax) of 100 K. Also, a highly collimated far‐field pattern is demonstrated, which is an important step towards real world applications. 相似文献
13.
Quantum cascade devices processed into double metal cavities with subwavelength thickness and a grating on top are studied at terahertz frequencies. The power extracted from the devices as a function of the device thickness and the grating period is analyzed owing to electrodynamical modeling of dipole emission based on a modal method in multilayer systems. The experimental data thus reveal a strong Purcell enhancement, with Purcell factors up to approximately 50. 相似文献
14.
15.
利用部分相干光理论对多色光源照明下光栅的菲涅耳衍射进行了理论分析,得到了适用于任意发光类型(脉冲或连续发光)的多色光源的衍射光强的一般公式,理论结果表明菲涅耳衍射区的平均衍射光强的形式只与光源的频谱分布有关,这对借助于连续发光光源来研究脉冲光源照明下光栅的塔尔博特效应以及用来确定脉冲光源的性能参量提供了有力的参考依据。此外,详细讨论了光源的频谱分布对光栅塔尔博特效应的影响并进行了相应的数值计算。实验中通过选用不同频率的激光分别照明光栅,拍摄到对应于不同频率的衍射光强分布图像,从而间接获得多色光同时照明光栅时总的衍射光强分布。实验结果表明,理论和实验符合较好。 相似文献
16.
We propose a spatial modulator for terahertz waves based on light induced electron plasma in photo-active semiconductors. A two-dimensional array of computer controlled light is used to create free carries in bulk silicon, which results in a spatial modulation of the transmission at terahertz frequencies. This method not only exhibits a remarkable modulation depth over a broad frequency range but also allows for an optically controlled beam steering of terahertz waves by inducing virtual grating structures. In addition, we analyze the possibility of all-optically controlled terahertz imaging. 相似文献
17.
Tunable terahertz plasmon in a graphene-based device with a grating serving as a top gate is studied. Transmission spectra exhibit a distinct peak in the terahertz region when the terahertz electric field is perpendicular to the grating fingers.Our results show that the extinction in the transmission of single-layer graphene shields beyond 80%. Electronic results further show that the graphene plasmon can be weakly adjusted by tuning the gate voltage. Theoretical calculation also implies that the plasmon frequency of graphene can fall into the terahertz region of 1–2 THz by improving the sustaining ability and capacitance of the top gate. 相似文献
18.
We discuss the transmission characteristics of a microscale dielectric waveguide device with a deep groove and an embedded metallodielectric grating illuminated by a continuous wave of TM and TE modes at low terahertz frequency. To study its performance we solve numerically the corresponding Maxwell equations by means of finite difference time domain method with uniaxial perfectly match layer as its boundary condition. By varying the angle of incident, grating filling factor and refractive index of analyte in the deep groove, it is found that the device exhibits a significant transmission enhancement for the TM mode due to the existence of surface plasmon interaction. We also demonstrate its potential application as a biosensor device. 相似文献
19.
Tunable terahertz radiation from arbitrary profile dielectric grating coated with graphene excited by an electron beam 下载免费PDF全文
《中国物理 B》2015,(9)
In this paper, the enhanced terahertz radiation transformed from surface plasmon polaritons, excited by a uniformly moving electron bunch, in a structure consisting of a monolayer graphene supported on a dielectric grating with arbitrary profile is investigated. The results show that the grating profile has significant influence on the dispersion curves and radiation characteristics including radiation frequency and intensity. The dependence of dispersion and radiation characteristics on the grating shape for both the symmetric and asymmetric gratings is studied in detail. Moreover, we find that, for an asymmetric grating with certain profile, there exist two different diffraction types, and one of the two types can provide higher radiation intensity comparing to the other one. These results will definitely facilitate the practical application in developing a room-temperature, tunable, coherent and miniature terahertz radiation source. 相似文献
20.
Citrin DS 《Optics letters》1999,24(7):472-474
The propagation of a weak light beam through a quantum well in the vicinity of an excitonic resonance that is modulated harmonically in time at terahertz frequency is considered. It is found that the reflection probability of the light beam is considerably different in the cases of purely coherent versus Gaussian incoherent terahertz modulation, even in the limit of long coherence times. 相似文献