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1.
Low-frequency fluctuations, which are typical irregular oscillations in edge-emitting semiconductor lasers, are experimentally observed for the y-polarization mode (y is the direction along the optical axis of a laser material) in a vertical-cavity surface-emitting laser with optical feedback.  相似文献   

2.
The nonlinear properties of semiconductor lasers and laser amplifiers when subject to optical injection are reviewed and new results are presented for multisection lasers, vertical cavity semiconductor optical amplifiers, and surface-emitting lasers. The main underlying material parameters are outlined and the key design approaches are discussed for both edge-emitting and vertical cavity devices. An overview of theoretical modeling approaches is discussed and a summary of key experimental results is presented. The practical use of optically injected edge-emitting and vertical cavity semiconductor lasers and laser amplifiers is illustrated with examples of applications including, among others, optical logic and chaotic communication.  相似文献   

3.
This paper will review and discuss pico- and femtosecond pulse generation from passively modelocked vertical–external-cavity surface-emitting semiconductor lasers (VECSELs). We shall discuss the physical principles of ultrashort pulse generation in these lasers, considering in turn the role played by the semiconductor quantum well gain structure, and the saturable absorber. The paper will analyze the fundamental performance limits of these devices, and review the results that have been demonstrated to date. Different types of semiconductor saturable absorber mirror (SESAM) design, and their characteristic dynamics, are described in detail; exploring the ultimate goal of moving to a wafer integration approach, in which the SESAM is integrated into the VECSEL structure with tremendous gain in capability. In particular, the contrast between VECSELs and diode-pumped solid-state lasers and edge-emitting diode lasers will be discussed. Optically pumped VECSELs have led to an improvement by more than two orders of magnitude to date in the average output power achievable from a passively modelocked ultrafast semiconductor laser.  相似文献   

4.
We investigate the physics of an internal device for a high-performance, vertical-cavity surface-emitting laser operating at 1.305 μm. Experimental results are analyzed using as the simulation software a photonic-integrated-circuit simulator in 3D (PICS3D), which is a state-of-the-art 3D simulator for surface- and edge-emitting laser diodes, semiconductor optical amplifiers, and other similar active waveguide devices. The 2D/3D semiconductor equations are coupled to the optical modes in both lateral and longitudinal directions. Optical properties such as the quantum well/wire/dot optical gain and spontaneous emission rates are computed self-consistently. Careful adjustments of material parameters led to an excellent agreement between simulation and measurements. Simulation results show that the maximum output power is limited by electron leakage from quantum wells.  相似文献   

5.
A novel hybrid surface-emitting laser and two-dimensional laser array is reported. The device consists of rectangular GaAs reflectors and edge-emitting single laser or one-dimensional laser arrays which are fabricated separately. The devices are mounted upside-down on a copper heat sink, allowing for good heat conduction. The CW operation and the reflectivity characteristics of this surface-emitting laser have been investigated.  相似文献   

6.
This paper gives a detailed theoretical investigation on phase conjugation induced by nearly degenerate fourwave mixing in single mode vertical-cavity surface-emitting lasers (VCSELs) with weak optical injection. Considering VCSELs that can work in linearly polarized or elliptically polarized states, it derives the theoretical expression of the conjugated field by small signal analysis based on the vectoral rate equations-the spin-flip model. For linearly polarized state, VCSELs show similar conjugate spectra to edge-emitting semiconductor lasers. For the elliptically polarized state, dichroism and birefringence parameters as well as the spin-flip rate can change the conjugate spectra. Especially, when frequency detuning of the probe and pump waves is between the positive and negative relaxation oscillation frequency, changes are evident. For specific values of parameters, conjugate efficiency between 20 dB to 40 dB are obtained.  相似文献   

7.
The critical design issues for unipolar silicon quantum-well intersubband lasers are investigated in this paper. Group IV lasing at near-infrared and middle-infrared wavelengths is analyzed for surface-emitting and edge-emitting geometries. Calculations show feasibility of SiGe/Si and SiGe/Si lasing. Silicon-on-insulator structures are proposed for index-guided lasers, vertical-cavity lasers and micro-cavity lasers  相似文献   

8.
基于激光光致发光光谱的果实成熟度测试方法研究   总被引:2,自引:0,他引:2  
介绍了一种探测果实成熟度的新方法。采用红光半导体激光器(655 nm)对果实样品进行照射,所得激光光致发光光谱在685 nm附近产生明显峰值。通过传统的糖度含量检测法测定样品的糖度含量,得到果实的激光光致发光光谱峰值强度随糖度含量增加而降低。利用最小二乘法原理对光致发光强度与糖度含量值进行比较分析,建立了两者的拟合曲线。以红心李和桃子为例, 两者之间的相关系数分别为98.92%与97.31%。设计针对该激光光致发光光谱检测系统的分析软件,实现了生成标准成熟光谱及检测未知成熟度的果实光致发光光谱两部分功能,通过比较可以自动得出果实成熟度等级的判定。结果证明,激光光致发光光谱的成熟度检测方法具有非破坏性、设备小型化、低能耗的优点,在果实成熟度的实时快速检测方面具有应用价值。  相似文献   

9.
Resonant tunnelling diodes with different structures were grown. Their photoluminescence spectra were investigated. By contrast, the luminescence in the quantum well is separated from that of other epilayers. The result is obtained that the exciton of the luminescence in the quantum well is partly come from the cap layer in the experiment. So the photoluminescence spectrum is closely related to the electron transport in the resonant tunnelling diode structure. This offers a method by which the important performance of resonant tunnelling diode could be forecast by analysing the integrated photoluminescence intensities.  相似文献   

10.
Bahl M  Rao H  Panoiu NC  Osgood RM 《Optics letters》2004,29(14):1689-1691
An approach based on the finite-difference time-domain method is developed for simulating the dynamics of passive mode locking in vertical-cavity surface-emitting lasers (VCSELs). The material response is modeled by the effective semiconductor Bloch equations through a resonant polarization term in the Maxwell's equations. Nonlinear gain saturation is incorporated through a gain compression factor in the equation governing the dynamics of the resonant polarization. An extended-cavity VCSEL with a quantum-well saturable absorber is simulated, and stable mode-locking pulses are obtained. Fine features of the spatial profile of the mode-locked pulses are also studied within this approach.  相似文献   

11.
The excitation of an aqueous solution of uranyl chloride by a 410-nm semiconductor LED and 266- and 448-nm lasers is found to induce intense photoluminescence: several bands in the blue-green spectral range (494 to 565 nm). Upon excitation of uranyl chloride aqueous solution by a 468-nm LED, the photoluminescence spectrum is a relatively narrow strong band peaking at 508 nm, which was interpreted as the transition from spontaneous photoluminescence to superluminescence. A lasing scheme (similar to that for dye lasers) has been proposed.  相似文献   

12.
The process of resonant photoluminescence of semiconductor quantum dots, which may serve as a basis for efficiently studying the dynamics of their electronic subsystem, is described theoretically. Potentialities of the spectroscopy of this type are analyzed using, as an example, the intraband relaxation of charge carriers in a quantum dot caused by their interaction with plasmons of doped regions of the heterostructure. Analytical expressions are obtained for the photoluminescence intensity, and conditions are found under which its spectrum provides the most explicit information about the intraband relaxation rates.  相似文献   

13.
One of the most application-relevant milestones that remain to be achieved in the field of passively mode-locked surface-emitting semiconductor lasers is the integration of the semiconductor absorber into the gain structure, enabling the realization of ultra-compact high-repetition-rate laser devices suitable for wafer-scale integration. We have recently succeeded in fabricating the key element in this concept, a quantum-dot-based saturable absorber with a very low saturation fluence, which for the first time allows stable mode locking of surface-emitting semiconductor lasers with the same mode areas on gain and absorber. Experimental results at high repetition rates of up to 30 GHz are shown. PACS 42.55.Px; 42.60.Fc; 42.82.Gw  相似文献   

14.
The threshold of semiconductor lasers is drastically reduced by injection of spin polarized electrons if the laser meets specific design rules. Taking into account the challenges of spin injection, spin transport, and spin relaxation, we discuss the threshold reduction in surface- and edge-emitting spin lasers at room temperature.  相似文献   

15.
The organic quantum well devices which are similar to the type-II quantum well of inorganic semiconductor have been fabricated. In the electroluminescence, the blue shift of spectrum with increasing applied voltage is observed, which is interpreted by exciton confinement effect and polarization effect, and the generation of exciton, including carrier injection and energy transfer, is discussed. This energy transfer from barrier to well is studied by photoluminescence and is interpreted in terms of Förster energy transfer. The electromodulation of photoluminescence demonstrates the quenching mainly comes from the dissociation of exciton in NPB and that in Alq3 is very stable.  相似文献   

16.
Using a micromanipulation technique, a planar photonic crystal nanocavity made from a thin semiconductor membrane is released from the host semiconductor and attached to the end facet of a standard single-mode optical fiber. The cavity spectrum can be read out through the fiber by detecting the photoluminescence of embedded quantum dots. The modified fiber end serves as a fiber-optic refractive index sensor.  相似文献   

17.
可以把垂直腔面发射激光器看作是多层光学薄膜,应用光学薄膜原理对其光学薄膜的特性进行了研究。计算分析了布拉格反射镜和谐振腔模的反射谱受器件结构变化的影响。通过利用菲涅耳系数矩阵法计算,得到了光在垂直腔面发射激光器器件结构中形成的驻波场分布。结果表明,利用菲涅耳系数矩阵法设计垂直腔面发射激光器的光学薄膜是一种快捷准确的方法。  相似文献   

18.
刘宁  张新平  窦菲 《物理学报》2012,61(2):27201-027201
利用稳态吸收和荧光光谱学、瞬态荧光光谱学(时间相关单光子计数技术)系统研究了EPPTC掺杂的F8BT薄膜异质结结构中激发复合体的形成机理和荧光发射特性,并表征了其特征光谱和荧光发射寿命. 其特征主要体现在显著延长的荧光发射寿命和红移的荧光发射光谱.这对于理解有机半导体材料异质结结构形成的机理和光物理学特性研究提供了多方面的实验依据.同时,由于这两种材料混合后的吸收光谱较宽范围地覆盖了可见光谱区,这样的有机半导体掺杂工艺对于有机光伏器件和太阳能电池器件的应用研究具有重要意义.  相似文献   

19.
We investigated the emission wavelength dependence of the lasing polarization in a (1 1 0)-oriented vertical-cavity surface-emitting laser (VCSEL) with GaAs/AlGaAs quantum wells under optical spin injection at room temperature. Lasing was observed in the one circularly polarized mode over a wide wavelength range from 838 to 857 nm, in which a degree of circular polarization higher than 0.8 was maintained. The optical gain spectrum that contributed to the circularly polarized lasing is discussed based on the optical selection rules and the measured polarization-resolved photoluminescence spectra of the active layers.  相似文献   

20.
王万录  高锦英 《发光学报》1992,13(4):341-346
本文研究了Cd2SnO4薄膜光致发光的某些性质.Cd2SnO4膜是利用Cd-Sn合金靶在Ar+O2气氛中反应溅射而成的.实验研究表明,Cd2SnO4膜的发光峰值随着氧浓度的增加移向长波方向.这是因为氧浓度的增加,减少了膜中的氧空位,导致了导带中电子浓度的减小,致使Burstein-Moss效应和电子散射作用相对减弱,从而改变了带隙宽度.  相似文献   

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