红外光谱的微分自消卷积

从理论上获得了高斯线型、洛伦兹线型的微分消卷积算符,对洛伦兹线型还给出了实用的消卷积算符。借助样条函数,利用获得的算符可分辨出Eu~(3+)的~7F_0→~5D_1跃迁在水溶液中的谱带结构,提高了原始光谱的分辨率。     

红外光谱消卷积的新方法

从理论上提出了用微分操作进行消卷积的新方法。借助样条函数,对Nd~(3+)位于870nm附近的吸收光谱进行了高斯线型的消卷积处理,提高了原始光谱的分辨率,与逐点松驰法和傅里叶变换法相比,具有参量选择少,计算简单,运算速度高等特点。     

激光钕玻璃中Nd~(3 )吸收光谱及斯塔克分裂的自消卷积分辨

本文利用自消卷积基本原理,对激光钕玻璃中Nd~(3 )的四个吸收带进行了自消卷积处理,消除了谱线本征线型,大大提高了光谱分辨率,从而在常温下确定了激光钕玻璃中Nd~(3 )的~4I_(9/2)、~4F_(3/2)能级及其斯塔克分裂。     

CdTe—ZnTe超晶格及其改进型结构一级声子喇曼散射分析

本文通过对常规结构CdTe-ZnTe超晶格和新型结构[(CdTe)_2-(ZnTe)_1]×9-(CdTe)_(60)复合超晶格一级声子喇曼峰位置和线型实验上和理论上的综合比较分析,证明新型结构因减小了晶格失配而使超过临界厚度的ZnTe层结构完整性得到很大改善。分析中首次强调指出一级纵光学声子峰线型对该类超晶格结构分析的重要性。     

光调制反射光谱中的高斯线形

本文提出了一种用于拟合计算光调制反射光谱的高斯线型表达式。通过对具体的Ｓｉ－－δ掺杂的光谱拟合计算并与常用的洛仑兹线形的计算进行的比较，显示了在非均匀展宽起重要作用情况下采用了高斯线型对实际光调制反射光谱分析是十分必要的。     

基于TDLAS技术的高斯线型二次谐波数值模拟与分析

作为新的痕量气体监测分析方法,可调谐二极管激光吸收光谱学的二次谐波技术在大气化学研究和污染气体监测得到实际应用。本文以CO气体的中心波长为λ0=1579.74nm的P（5）振-转吸收谱线为目标,建立高斯线型的二次谐波信号数值模型,仿真得到二次谐波曲线,研究了二次谐波信号特性与调制度m的关系。并对仿真结果与洛仑兹吸收线型二次谐波信号特性进行了分析和比较。     

关于超荧光

本文对于初始就处于粒子数反转的二能级系统,借助二次量子化,引用电子和光子的产生,湮没算符,建立了全量子方程组。该方程组包含着自发辐射、受激辐射和协作辐射三种过程。变量取c——数时,得到一组速率方程。(1)同人们以往得到的使用能量自旋算符的全量子方程组以及关于超辐射的各种形式的速率方程进行了比较讨论;(2)指出了在忽略协作辐射情形下,它们成为通常     

消除高强度光腔三光子过程中两能级原子的消相干性

研究置于外部环境(热库)中的两能级原子在外加驱动场时原子的消相干问题.得到高强度光腔三光子过程中原子约化密度算符非对角元.在两能级原子的消相干被消除的情况下,讨论外加驱动场的特性.     

用超算符方法求解压缩热库中两能级原子的主方程

利用超算符的方法，给出了在压缩热库情况下，两能级原子主方程的超算符求解，从而可从任意的初态容易地得到密度算符的解析表达式。     

存在各种增宽机制下的综合加宽线型函数

本文提出一种对激光物理学中谱线综合加宽问题的统一处理方法。从理论上推得任意两种增宽的综合加宽线型函数为各自线型函数的卷积,并分析了存在各种增宽机制下的综合加宽线型函数。     

佛克脱光谱线型半高宽的理论研究

根据我们利用傅里叶变换方法得到的精确佛克脱线型的表达式,利用泰勒级数计算了佛克脱线型、高斯线型和洛伦兹线型半高宽之间的关系.画出了三者之间的关系曲线,并对结果进行了讨论.通过进一步讨论,发现佛克脱线型与高斯线型半高宽之比和洛伦兹线型与高斯线型半高宽之比的关系为第一象限的四分之-椭圆.此方法对于实际应用非常方便而且具有很好的准确性.     

Correlation of photoluminescence linewidths with carrier concentration in p-Ga0.52In0.48P

We find a statistically significant correlation between carrier concentration and the Lorentzian linewidth factor determined from a Voigt lineshape fit to roomtemperature photoluminscence (PL) measurements for partially ordered p-Ga_0.52In_0.48P epitaxially deposited by organometallic vapor-phase deposition on GaAs. The correlation is independent of the amount of ordering present in the material. For carrier concentrations over the range of ~10¹⁶ to 10₁₉ cm₋₃, PL provides rapid and nondestructive evaluation, with increasing accuracy above carrier concentration levels of 5 × 10¹⁷ cm₃.     

Direct observation of Lorentzian lineshape of semiconductor laser and linewidth reduction with external grating feedback

The Lorentzian lineshape of a single longitudinal mode AlGaAs semiconductor laser is directly observed by optical heterodyne detection. A remarkable reduction in the spectral linewidth to less than 50 kHz is achieved with external grating feedback. The experimental linewidth is in reasonable agreement with the theoretical value, which is obtained by finesse calculation of the active Fabry-Perot cavity.     

Bragg section effects on linewidth and lineshape in 1.55-/spl mu/m DBR tunable laser diodes

We report linewidth and lineshape measurements on 1.55-/spl mu/m distributed Bragg reflector tunable laser diodes using the heterodyne method. We measure Lorentzian linewidths ranging from 3.5 to 25 MHz without any passive section injection. Biasing the Bragg section enhances the residual linewidth up to 6.2 MHz, changes the linewidth-power product, and brings an additional Gaussian lineshape. The feedback sensitivity of the overall setup is also demonstrated.     

Radiation emitted by InGaAs quantum-well structures. II. Homogeneous lineshape function

The shape of the spontaneous-emission spectra of quantum-well InGaAs structures is analyzed in a wide current interval at temperatures 4.2–286 K. Using a modified homogeneous lineshape function, an interpretation of the band shape for transitions between the lowest subbands is given and the nature of its non-Lorentzian contour is discussed. The properties of a family of functions exhibiting a continuous transition from a Lorentzian to a Gaussian lineshape are discussed. They could be suitable for modeling spectra in the case of non-Markovian collisional relaxation. Fiz. Tekh. Poluprovodn. 32, 478–483 (April 1998)     

Theoretical analysis of 630-nm band GaInP-AlGaInP strainedquantum-well lasers considering continuum states

GaInP-AlGaInP strained quantum-well lasers with emission wavelength at 630-nm band are theoretically analyzed in detail and then optimized. The valence band structure of quantum wells is obtained by evaluating the 6×6 Luttinger-Kohn Hamiltonian including the coupling among the heavy hole, the light hole, and the spin-orbital spilt-off hole bands. The effect of optical transition from/to continuum states not confined to the quantum well is studied. It is found that the optical transition from/to the continuum states is serious as the band gap of the confining layers is close to the quasi-Fermi level separation, leading to considerable radiative current. This radiative current is undesirable since the corresponding optical transition does not contribute significantly to the threshold gain. The gain-radiative current characteristic is therefore poor for confining layers containing a low Al content. To avoid unreasonable gain/absorption, the non-Markovian convolution lineshape is used instead of the conventional Lorentzian lineshape. The leakage current is high for single quantum-well lasers with wide bandgap confining layers, it can be reduced by increasing the quantum-well number, the dopant concentration, and the band gap of cladding layers. The calculated threshold current agrees well with the observation. The band gap shrinkage due to the carrier-carrier interaction is considered to obtain an emission wavelength consistent with the experimental result     

洛伦兹介质电磁特性分析的通用FDTD方法

针对窄带、宽带及其临界情况时洛伦兹介质对应不同时域表达式而导致的递归卷积、Z变换等常用色散介质FDTD方法的更新公式无法通用问题,提出一种改进的移位算子FDTD方法,该方法保持了原方法概念简明、推导简单的优点,减少了内存占用,提高了计算速度,对窄带、宽带及其临界情况洛伦兹介质具有完全相同的更新公式。最后,通过具体算例验证了算法的有效性。     

延时自外差法线宽测量误差分析仿真及修正

讨论了移频延时自外差探测的基本原理,并对外差得到的功率谱进行了公式推导。在此基础上,对外差测量中出现的测量误差进行分析,同时设计了自外差测量实验装置进行实验对比,确定了由于延时线长度不够导致的线宽测量误差来源是因为延时时间短导致幂指数函数项波动加剧造成的;同时针对外差信号频谱为洛仑兹型和类高斯型的混合谱型,在高斯功率谱密度函数的基础上,对延时时间和1/f谱宽的影响进行了仿真计算,采用Voigt分析,提取出1/f导致的测量误差,提高了线宽测量的精度。以高斯谱宽4.5 kHz的谱型为例,对应的洛仑兹线宽约为0.68 kHz,提高了一个数量级的测量精度。     

波长调制光谱检测下限计算方法的研究

在基于波长调制光谱技术的大气痕量气体检测下限计算方法的研究中,全面准确地描述吸收信号及噪声的大小极为重要。为了探讨半导体二极管激光器在进行波长直接调制时伴随产生的残余振幅调制噪声对检测下限的影响,在理论推导中采用了一种同时考虑波长和振幅调制的二次谐波信号分析及提取方法,以二次谐波信号峰谷差值作为系统的检测信号,对可调谐二极管激光器吸收光谱检测系统的信噪比和检测下限进行了理论分析,取得了洛伦兹吸收线型条件下残余振幅调制噪声对系统信噪比和检测下限的影响的精确计算数据。结果表明,在吸收线的线宽较大的检测条件下,残余振幅调制噪声是影响检测下限的重要因素。