共振声子太赫兹量子级联激光器研究

本文综述了共振声子太赫兹(THz)量子级联激光器(QCL)载流子输运及其光电特性的研究结果。我们采用Monte Carlo方法模拟了不同有源区结构的共振声子THz QCL,如四阱有源区和三阱有源区结构等,优化了THz QCL的器件参数。计算表明,器件的增益依赖于注入势垒的宽度、掺杂浓度和声子抽运能级间隔等参数。单阱注入的THz QCL可以获得低的激射频率,而三阱有源区结构的THz QCL具有更高的工作温度。我们数值模拟了这两种器件结构在不同寄生电压下的电子输运、增益以及温度特性等。同时,我们实验测量了THz QCL的发射谱偏压和温度效应,计算结果与实验相吻合。研究结果表明,随着偏压增加发射谱出现了明显的频率蓝移,多模激射仅出现在大电流注入情形。与偏压的密切依赖关系不同,激射频率对温度的变化并不敏感。     

Study of the Spectra of Arched-Cavity Quantum-Cascade Lasers

Optics and Spectroscopy - The temperature characteristics of arched-cavity quantum-cascade lasers with different geometrical dimensions emitting in the spectral range of 7–8 μm are...     

Mid-IR Range Quantum-Cascade Lasers in Compact Optoacoustic Gas Analyzers

Journal of Applied Spectroscopy - The generation regimes of quantum-cascade lasers for optoacoustic sensors of methane and ammonia are examined, and the tuning and output characteristics of these...     

布拉格反射波导激光器的光谱特性（英文）

设计并制备了基于双边非1/4波长布拉格反射波导的边发射半导体激光器,中心腔采用低折射率材料,在垂直方向利用布拉格反射进行光限制,实现了超大光斑尺寸且稳定单横模工作。10μm条宽、未镀膜的脊型激光器在准连续和连续工作方式下的总的输出功率分别超过了170 mW和80 mW,且最高功率受热扰动限制。激光器远场图案在垂直方向为双瓣状,单瓣垂直方向和水平方向发散角分别低至7.85°和6.7°。激射谱半高全宽仅为0.052 nm,光谱包络存在周期性调制现象,模式间隔约为3.3 nm。电流增加到300 mA以上时,激光器出现模式跳变。     

Influence of Nonlinear Refraction on the Spectral Characteristics of GaAlAs/GaAs Lasers

Numerical modeling of the spectral characteristics of single-frequency lasers is carried out by using a model which takes into account nonlinear refraction. It is shown that account for nonlinear refraction allows one to obtain satisfactory coincidence of the experimental and theoretical spectral characteristics of quantum-well lasers.     

基于可调谐激光的光谱辐射照度响应度定标

探测器的光谱辐射照(亮)度响应度是辐射定标中最重要的参数之一.传统的光谱辐射定标采用宽谱段光源和单色仪装置测量,新建的激光辐射测量装置采用激光和探测器测量,可以大大降低测量的不确定度.该装置首先将可调谐激光耦合进入积分球生成均匀的朗伯体单色光源,然后采用低温辐射计量传的标准陷阱探测器和面积已知的光阑,进行400～900...     

分布布拉格反射光纤激光器的特性分析

利用耦合模理论和数值方法,对分布布拉格反射光纤激光器的特性进行分析,对利用不同光栅作反射镜的激光器阈值增益谱进行了比较。为进一步的设计与制作提供了理论指导。     

Multi-transverse Mode Operation in Vertical-cavity Surface-emitting Lasers: Effects of Wideband Modelling on Spectral Characteristics and Noise

A dynamic model for the vertical-cavity surface-emitting laser aimed to study the precise oscillation frequencies of the transverse modes is presented. The model performs the computation of the longitudinal distribution of the field inside the laser cavity, to take account of distributed boundary conditions at the Bragg reflectors. The latter are approximated by means of autoregressive moving-average (ARMA) digital filters, in order to reduce the computational load without loss of precision in wideband scenarios. With the aid of the developed model, a detailed analysis of the frequency and relative intensity noise spectra is carried out, thus allowing to evaluate the spectral quality of the laser emission. Particularly, the results reveal that each of the transverse modes oscillates with a frequency detuning from the central design wavelength, which is in good agreement with experimental observation.     

光纤激光器谱合成系统合成效率的计算分析

在简化模型的基础上,从三能级粒子速率方程出发,结合光纤激光器的光束传输方程,推导出光纤激光器谱合成系统的输出功率和合成效率的解析表达式.在此基础上,对合成效率进行了计算分析,并讨论了影响合成效率的主要因素.结果表明,光纤激光器谱合成系统的合成效率主要由光纤激光器输出镜反射率、谱合成系统的外腔输出镜反射率、光栅衍射效率以及望远镜滤波组件透过率决定.     

基于级联体光栅的光纤激光阵列谱组束

提出了一种基于级联体光栅(VBG)的谱组束方案,组柬阵元数可随级联体光栅的数目倍增.给出了一个双光栅级联谱组束系统实例,将组束阵元按波长分为两组,利用具有相应波长选择性的体光栅分别对它们进行组束,由于两个级联体光栅的角度选择性互不重叠,所有光束经第二个体光栅后都沿其布拉格(Bragg)角方向出射,实现近场和远场的功宰叠加.为保证各光束传播方向的一致性,采用严格耦合波理论推导出了准确计算光束入射角的解析式.数值计算结果表明各光束的平均衍射效率优于80%,在入射角偏离理论值不超过±5'(≈2.424×10-5rad)的条件下组束光中所有光束的传播方向偏差小于4×10-7rad.     

Spectral Properties of the Radiation of Injection Lasers at Prethreshold Excitation Levels

The spectral properties of the radiation of injection lasers at low (prethreshold) levels of excitation were investigated experimentally by the method of optical heterodyning of the Doppler signal and also with the use of a KSVU23 spectral setup. It is established that these lasers may serve as sources of the optical radiation of TE and TMpolarizations with a retuned length of coherence within the range 1–10 mm in spectrometric facilities of photoheterodyne type. A procedure for determining the inversion current in an injection laser is suggested.     

Spectral Beam Combining of Fiber Lasers by Using Reflecting Volume Bragg Gratings

By employing three reflecting volume Bragg gratings,a near-infrared 4-channel spectral-beam-combining system is demonstrated to present 720 W combined power with a combining efficiency of 94.7%.The combined laser beam is near-diffraction-limited with a beam factor M~2~1.54.During this 4-channel beam-combining process,no special active cooling measures are used to evaluate the volume Bragg gratings as combining elements are under the higher power laser operation.Thermal expansion and period distortion are verified in a 2kW 2-channel beam-combining process,and the heat issue in the transmission case is found to be more remarkable than that in the diffraction case.Transmitted and diffracted beams experience wave-front aberrations with different degrees,thus leading to distinct beam deterioration.     

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。     

Control of Spectral Extreme Events in Ultrafast Fiber Lasers by a Genetic Algorithm

Extreme wave events or rogue waves (RWs) are both statistically rare and of exceptionally large amplitude. They are observed in many complex systems ranging from oceanic and optical environments to financial models and Bose–Einstein condensates. As they appear from nowhere and disappear without a trace, their emergence is unpredictable and non-repetitive, which makes them particularly challenging to control. Here, the use of genetic algorithms (GAs), which are exclusively designed for searching and optimizing stationary or repetitive processes in nonlinear optical systems, is extended to the active control of extreme events in a fiber laser cavity. Feeding real-time spectral measurements into a GA controlling the electronics to optimize the cavity parameters, the wave events are able to be triggered in the cavity that have the typical statistics of RWs in the frequency domain. The intensity of the induced RWs can also be tailored. This accurate control enables the generation of optical RWs with a spectral peak intensity 32.8 times higher than the significant intensity threshold. A rationale is proposed and confirmed by numerical simulations of the laser model for the related frequency up- and downshifting of the optical spectrum that are experimentally observed.     

大环二芳基庚烷类化合物的波谱特征

通过查阅国内外相关文献和书籍,对大环联苯型二芳基庚烷和大环二苯醚型二芳基庚烷类化合物的结构特征,紫外,红外,核磁共振波谱和改良Mosher法测定绝对构型进行综述. 现已研究的来源于天然产物的大环二芳基庚烷类化合物结构上各具特征,尤以大环二苯醚型二芳基庚烷类化合物6位H最有代表性. 大环二芳基庚烷类化合物波谱特征的研究为人们鉴定结构提供了重要的依据.     

马达加斯加玛瑙的光谱学特征研究

玛瑙在世界各地分布广泛,有关玛瑙矿物学和光谱学特征的研究颇丰,但对产自马达加斯加安楚希希市和马哈赞加省的玛瑙的光谱学和产地特征研究甚少.采用正交偏光显微镜、红外光谱和拉曼光谱仪对5块来自安楚希希市和马哈赞加省具有纹带结构的玛瑙样品进行光谱学特征分析.结果表明:这两个产地玛瑙的主要矿物成分一致,均为α-石英和斜硅石.来自...     

夫琅禾费衍射的光谱特性

基于MATLAB语言,以夫琅禾费衍射为研究对象,数值模拟了夫琅禾费圆孔衍射和单缝衍射光谱特性,通过改变狭缝宽度和入射波的波长,数值模拟得到夫琅禾费单缝衍射的光强变化图和光谱特性图。结果表明,圆孔衍射的光强比单缝衍射的光强曲线在次级明纹的强度更加低,夫琅禾费衍射的结论与实际理论和试验吻合的较好。研究结果为夫琅禾费衍射的研究提供参考。     

Optical Feedback Characteristics in He-Ne Dual Frequency Lasers

Optical feedback characteristics in He-Ne dual frequency lasers are studied systematically in different feedback power ratios with a variable attenuator. Feedback power ratios vary from 0.010 up to 0.998. Five distinct regimes of self-interference effects are found and defined as regimes Ⅰ, Ⅱ,Ⅲ,Ⅳand Ⅴ. Accordingly, five optical feedback levels have been put forward in He-Ne dual frequency lasers. Strong mode competitions are observed in regimes Ⅲ and Ⅳ. In regime Ⅴ, multiple feedback effects are investigated. The basic theoretical analysis is also presented. Our results can advance the research of self-mixing interferometer and displacement sensor of He-Ne orthogonally polarized dual frequency lasers.     

矩形结构垂直腔顶发射激光器的偏振特性

为了获得高功率的偏振激光,对矩形结构的980 nm大口径顶发射垂直腔面发射激光器(VCSEL)进行了研究.实验结果显示,对于400 μm×80μm出光口径的矩形VCSEL器件,在工作电流内,水平偏振光和竖直偏振光共同存在,并且水平偏振光一直占据主导地位;而且水平偏振光的光谱相对于竖直偏振光有蓝移.这些现象和理论模型的分...