∧型双模激光的朗之万理论

采用朗之万激光理论讨论∧型双模激光近阈运行的模式耦合特性，双模既可以呈现相互抑制和相互支持，又可以呈现一模被抑制另一模被支持以及－模或双模既不被支持又不被抑制。耦合特性不仅取决于双模失谐量，而且与原子三能级初始布居紧密相关。     

Λ型双模激光的朗之万理论

采用朗之万激光理论讨论型双模激光近阈运行的模式耦合特性，双模既可以呈相互抑制和相互支持，又可以呈现一模被抑制另一模被支持以及一模或双模既不被支持又不被抑制。耦合特性不仅取决于双模失谐量，而且与原子三能级初始布居紧密相关。     

双模激光的非共振运转

本文将Lamb的激光量子理论推广应用于处理均匀展宽三能级原子系统中的双模激光运转。在相等失谐的情况下,分别求得了双模运转下的平均光子数、频率方程和线宽表达式,讨论了偏调的影响。     

双光子双模激光的朗之万理论

采用朗之万量子理论讨论双光子双模激光近阈运行的模式耦合.耦合的特性,既可以呈现相互支持和模2被支持模1被抑制的情形,也可以呈现模1被支持模2被抑制和一模被支持另一模既不被支持也不被抑制的情形.耦合的特性不但取决于双模的失谐量,而且取决于三能级的初始布居数. 关键词：     

双模压缩真空场与Λ型三能级原子非共振作用

研究了双模压缩真空场与Λ型三能级原子非共振相互作用系统中,场模失谐量对原子布居概率和光场的双模互关联函数、二阶相干度的影响.结果表明：失谐量使原子Rabi振荡呈现周期性崩塌与复苏现象；当光场初始压缩因子r较小时,失谐量将削弱光子的反聚束效应；当r较大时,失谐量又将增强光场两模相关的稳定性.     

中性原子的激光导引及其应用

文章综述了采用中空光纤中红失谐高斯模式,红失谐高斯激光束,中空光纤中蓝失谐消逝波和蓝失谐暗中空光束实现中性原子激光导引的原理,方法和实验及其最新进展,并简单介绍了激光导引原子技术在原子光学领域中的应用。     

双模纠缠相干光场与V型三能级原子相互作用系统的原子偶极压缩效应

采用求解Schroedinger方程和数值计算方法，研究了双模纠缠相干光场与V型三能级原子相互作用过程中原子偶极算符的压缩效应，结果表明：此压缩效应与双模纠缠光场的纠缠程度、失谐量相关联。     

Ⅴ型三能级原子与双模奇偶纠缠相干光场相互作用系统的光子统计性质

本文采用求解Schroedinger方程和数值计算方法，研究了Ⅴ-型三能级原子与双模奇偶纠缠相干光场相互作用系统的光子统计性质，结果表明：此性质与双模奇偶纠缠相干光场的纠缠程度、失谐量、原子的初态以及双模光的平均光子数相关联．     

双模纠缠相干光场与V型三能级原子相互作用系统的光子统计性质

本文采用求解Schrodinger方程和数值计算方法,研究了双模纠缠相干光场与三能级原子相互作用系统的光子统计性质,结果表明:此性质与双模纠缠相干光场的纠缠程度、失谐量、双模光的平均光子数和原子的初态相关联.     

V型三能级原子与双模奇偶纠缠相干光场相互作用系统的光子统计性质

本文采用求解Schr dinger方程和数值计算方法,研究了V-型三能级原子与双模奇偶纠缠相干光场相互作用系统的光子统计性质,结果表明:此性质与双模奇偶纠缠相干光场的纠缠程度、失谐量、原子的初态以及双模光的平均光子数相关联.     

Self-suppression of axial mode hopping by intracavity second-harmonic generation

Intracavity second-harmonic generation (SHG) in a single-frequency laser has an associated loss for adjacent nonlasing modes, from sum-frequency generation, that is greater than the loss from SHG for the lasing mode. Mode hopping is thereby suppressed, as the lasing mode dominates neighboring modes. We have investigated this behavior in a Nd:YAG laser with LBO intracavity frequency doubler, obtaining frequency tuning over more than 80 axial mode spacings, without mode hopping.     

Adsorbate motions induced by vibrational mode coupling

Adsorbate motions are discussed with a primary attention focused on the coupling between a vibrational mode excited by ultrafast laser heated hot-electrons or by inelastic tunneling electrons with scanning tunneling microscope and the reaction coordinate (RC) mode. Recent experimental results have demonstrated an efficient reaction pathways involving an indirect excitation of a frustrated translational mode, rather than its direct excitation for adsorbate hopping on surfaces. Elementary processes are briefly described for hopping of CO molecules on a laser heated stepped Pt surface, where excitation of the frustrated rotation mode has been found to plays an indispensable. Calculation of the inelastic tunneling current (ITC) for excitation of the C-O stretch mode of a CO molecule is combined with a theory of anharmonic mode coupling to activate the frustrated translation mode above the barrier. The hopping rate as a function of the bias voltage agrees with the experimental result. An unified theory of single-, and two-electron processes for ITC-induced motions induced by an indirect excitation of the RC-mode via mode coupling is also applied to reproduce a crossover from hopping to desorption of a single NH₃ molecule on Cu(1 0 0) with an increase in the tunneling current.     

Synchronization of chaotic mode hopping

We propose and demonstrate a scheme for generating synchronized chaotic mode hopping in two wavelength-tunable lasers whose tuning range covers multiple longitudinal modes. Chaotic mode hopping resulting in large hops in wavelength is induced by delayed electrical feedback. We show that, by coupling part of the output of one laser into another, one can synchronize the chaotic mode hopping of two separate lasers and obtain synchronized chaotic on-off modulation patterns in multiple corresponding wavelength bands.     

短外腔偏振旋转光反馈下1550nm垂直腔面发射激光器的动力学特性研究

基于扩展的自旋反转模型,对短外腔偏振旋转光反馈下1550 nm垂直腔面发射激光器的动力学特性进行了数值仿真和理论分析.研究结果表明:增加反馈强度会导致多个偏振开关现象出现,中等反馈强度下呈现丰富的动力学状态,譬如单周期、倍周期、准周期及混沌态,增加注入电流使Y方向线偏振模的工作区域被压缩;随着反馈延迟时间的增加,在弱光反馈时,偏振模跳变现象将会以特定的频率发生,施加中等的反馈强度将会导致模式跳变的频率增加,并且出现各种新的动力学状态,包括拍频单周期、拍频脉冲包络、拍频准周期和拍频混沌态.新动力学行为的出现是由于短外腔区激光器的动力学特性对相位变化非常敏感,从而使外腔模式间的拍频效应发挥了关键作用.此外还发现各种动力学状态之间会伴随模式间的跳变而发生相互跳变.     

基于二次反馈激光自混合新型测距方法

在基于激光自混合干涉的理论上,提出了一种利用二次反馈激光自混合干涉的新型测距方法。利用三角波电流对半导体激光器进行调制,得到一次反馈自混合干涉信号。通过对信号分析可知,当半导体激光器被调制后,会产生一系列的模跳,模跳的数量与绝对距离成正比。通过计算在一个三角波电流调制周期内模跳的数量,就可以求出绝对距离。利用多重激光自混合的概念,提出该种新型测距方法。建立了距离测量系统,进行了实验验证。实验结果表明:由于步长分辨率精度的提高,测距精度明显提高。     

二极管激光泵浦Nd：YVO4激光器的频率调谐特性研究

用加热法和压电陶瓷ＰＺＴ调腔的方法，实现二极管激光泵浦的单频运转１０６４ｎｍ２％Ｎｄ：ＹＶＯ４激光器调谐。调谐范围４７．４ＧＨｚ，增益峰漂移引起的激光频率温度系数２ｖ／２Ｔ＝－１．０４ＧＨｚ／℃，压电陶瓷调谐系数１５０ＭＨｚ／Ｖ。研究了加热影响件性能的情况。     

Continuously tunable, high-power, single-mode radiation from a short-pulse free-electron laser

This paper gives the first demonstration of high-power, continuously tunable, narrowband radiation that is produced by means of a free-electron laser (FEL) in the far-infrared region of the electromagnetic spectrum. A Fox-Smith intracavity étalon was used to induce phase coherence between the 40 optical micropulses that were circulating in the laser cavity. The corresponding phase-locked spectrum consisted of a comb of discrete frequencies separated by 1 GHz. A pair of external Fabry-Pérot étalons was used to filter out a single line from this spectrum. The power in the selected narrow line at 69 microm wavelength was equal to 250 mW during the macropulse of the laser. The spectral width of the selected line is as small as that of a single cavity mode, i.e., a fraction of 25 MHz, in single macropulses of the laser. The average bandwidth of 25 MHz is determined by mode hopping of the phase-locked FEL. The selected frequency hops over 25 MHz between the extrema of this band. The influence of partially coherent spontaneous emission and mode hopping on the final linewidth was studied. The narrow-linewidth radiation was scanned in frequency over 1 GHz. We show that the possibilities to scan over smaller or larger frequency intervals are unlimited.     

Single-longitudinal-mode erbium-doped fiber laser with the fiber-Bragg-grating-based asymmetric two-cavity structure

We present a simple and stable single-longitudinal-mode (SLM) erbium-doped fiber linear-type laser. It consists of three FBGs directly written in a photosensitive erbium-doped fiber (PEDF) to form asymmetric two cavities with different cavity lengths, which can effectively increase the longitudinal mode spacing and suppress mode hopping, experimentally compared with symmetric two cavities and single-cavity structures. The stable SLM operation is conveniently achieved without accurate control of cavity length, and the laser linewidth of less than 5 kHz is acquired.     

Two-wavelength speckle interferometry on rough surfaces using a mode hopping diode laser

Two measurements performed on rough surfaced objects are described in this paper. The first sample is a mechanical component with a rather difficult accessible surface to be measured. A two-wavelength krypton laser interferometer with an effective wavelength of 36.47 μm has been used. The second example is a convex surface of a ground lens. Here a mode hopping diode laser interferometer with an effective wavelength of 2·020 mm has been used.     

Wavelength-selection erbium fiber laser with single-mode operation using simple ring design

In this demonstration, we propose and experimentally investigate a wavelength-selection erbium-doped fiber (EDF) laser in single-longitudinal-mode (SLM) by using simple fiber ring scheme design. We use a tunable bandpass filter (TBF) inside the gain cavity to restrict the lasing frequency. The proposed ring cavities can also serve as the mode filters for side mode suppression. Based on the simple ring cavity design, the mode hopping can be avoided to achieve SLM output. The TBF inside the laser scheme also obtains the wavelength tuning in the range of 1520.02 to 1562.02 nm. In addition, the output performance of the proposed fiber laser has also been discussed.