多光子光学双稳性的复振幅解析分析

本文应用线性化稳定性分析方法,对用半经典的麦克斯韦-布赫(Maxwell-Bloch)方程描述的多光子光学双稳性进行了复振幅分析.分析的结果表明:在对极化量进行绝热消除后,多光子光学双稳性特性曲线上合作支和单原子支不存在失稳问题,同时说明由软模不稳定性引起的多光子光学双稳性的混沌态不存在,并指出稳定性的第三个条件是双稳性存在的条件.     

多光子光学双稳性的研究

本文给出了描述多光子光学双稳性和多光子激光的统一量子力学模型,得到了多光子光学双稳性和多光子激光的态方程,给出了计算多光子光学双稳住阈值的方法.对势函数进行分析之后,得到了静态稳定性判据和开关特性的物理解释,划分了多光子光学双稳特性曲线上的稳定区域和亚稳定区域,指出多光子光学双稳态实际上是多光于光学稳-亚稳双态.本文还讨论了多光子光学双稳态和多光子激光器中的相变问题.     

光学双稳性的强迫振动模型

本文提出一个新的光学双稳性模型.基于平均场近似,慢变振幅近似和绝热近似的思想,把光学双稳系统看成一个“黑箱”,类比非线性振动理论,指出不同的光学双稳过程(包括不同的工作物质和不同的腔(F-P腔或环腔)),能用一个恰当的强迫振动方程统一地描述.方程中所包含的都是可测量的宏观参量,使得可能直接用实验拟合,与理论结果进行定量对照.用振动理论的方法,把方程演变成自治方程组,从而方便地得到光学双稳性稳态和动态解的一般形式.并用若干已报道的具体例子验证了这个模型的普适性.     

ZnSe／ZnS多量子阱激子光学双稳性

用MOCVD在CaF_2衬底上生长的ZnSe/ZnS多量子阱材料,在77K下用N_2激光泵浦染料获得的宽带光脉冲进行了非线性光学测量,首次观察到ZnSe/ZnS多量子阱的激子光学双稳性,据分析这是由激子的能带增宽效应引起的增强吸收光学双稳性.     

光学双稳性的尖顶突变模型

本文提出一个描述光学双稳性的简明的突变理论模型,由此得到产生光学双稳性的阈值条件,并指出控制双稳特性的方法.     

反馈调谐CO2激光器的静态与动态行为

建立了反馈调谐CO_2激光器的物理数学模型.稳态分析结果表明,只有当反馈系数大于某一临界值之后,才能出现激光器泵浦速率与激光输出之间的光学双稳性.线性稳定性分析的结果表明,系统失稳的必要条件是失谐量的Debye弛豫速率(反馈系统的带宽)必须超过布居反转的衰减速率.只有当激光泵浦落在某一范围内时,才出现不稳性.数值分析的结果证明了系统输出倍的周期分岔混沌行为.线性稳定性分析预言的Hopf分岔频率与数值分析的结果符合得很好.     

10.784μm无镜斯塔克效应光学双稳性

利用同位素C~(13)O_2~(16)激光器R(18)支线与NH_3分子(as)_Q(6,6)跃迁间的相互作用,观察到了斯塔克效应光学双稳性和光学限幅,分析了含有多普勒加宽的稳态理论,实验结果与理论分析结论一致.     

扫描法布里—珀罗光学双稳态装置

提出一种不含非线性介质的新型双稳态光学装置,用一个具有反馈的扫描F-P干涉仪和一台单模激光器显示光学双稳性。文中介绍了这种装置的原理、特性和实验结果。     

光学双稳态装置研究进展

光学双稳性(Optical Bistability)是光波通过某种光学装置强度发生非线性变化的特性,　对应某一输入光强存在着两个或多个稳定的输出光强状态.这是属于量子电子学的非线性光学领域的一个新研究课题.利用光学双稳性可以制成具有光开关、光存储、光放大等功能的光学器件,具有开关     

非线性吸收诱导掺镱光纤激光器中的光学双稳

研究了在掺镱光纤激光器中观察到的光学双稳态现象.激光信号光和驻留泵浦光的双稳特性来源于激光器在小信号和增益饱和两种情况下,掺镱光纤对信号的非线性吸收导致的激光器内腔非线性损耗.同时分析了把泵浦光中的光学双稳行为通过分叉的腔结构扩展到切换式双波长光纤激光器的可行性.     

Optical bistability and multi-stability in a four-level atomic scheme

We investigate the optical bistability (OB) and optical multi-stability (OM) in a four-level Y-type atomic system. It is found that the optical bistability can strongly be affected by intensity and frequency detuning of coupling and probe fields. The effect of spontaneously generated coherence on phase control of the OB and OM is then discussed. It has also been shown that the optical bistability can be switched to optical multi-stability just by the quantum interference mechanism and relative phase of applied fields.     

Controlling the optical bistability via quantum interference in a four-level N-type atomic system

We investigate the optical bistability (OB) and optical multi-stability (OM) in a four-level N-type atomic system. The effect of spontaneously generated coherence (SGC) on OB and OM is then discussed. It is found that SGC makes the medium phase dependent, so the optical bistability and multi-stability threshold can be controlled via relative phase between applied fields. We realize that the frequency detuning of probe and coupling fields with the corresponding atomic transition plays an important role in creation OB and OM. Moreover, the effect of laser coupling fields and an incoherent pumping field on reduction of OB and OM threshold is then discussed.     

Observation of Optical Bistability and Multi-Stability in the Dielecrtric Slab Doped with a Quantum well Waveguide

The optical bistability (OB) and multi-stability (OM) behavior in a dielectric slab medium doped with semiconductor quantum well nanostructure has been discussed by employing the spin coherence effect. It is shown that, by changing the relative phase of applied fields the bistable behavior switches from OB to OM or vice versa in a dielectric medium. The effect of the frequency detuning of laser fields on the OB and OM behavior are also discussed in this paper.     

Optical bistability via quantum interference from incoherent pumping and spontaneous emission

We theoretically investigate the optical bistability (OB) in a V-type three-level atomic system confined in a unidirectional ring cavity via incoherent pumping field. It is shown that the threshold of optical bistability can be controlled by the rate of an incoherent pumping field and by interference mechanism arising from the spontaneous emission and incoherent pumping field. We demonstrate that the optical bistability converts to optical multi-stability (OM) by the quantum interference mechanism.     

Optical bistability induced by quantum coherence in a negative index atomic medium

Bistability behaviors in an optical ring cavity filled with a dense V-type four-level atomic medium are theoretically investigated. It is found that the optical bistability can appear in the negative refraction frequency band, while both the bistability and multi-stability can occur in the positive refraction frequency bands. Therefore, optical bistability can be realized from conventional material to negative index material due to quantum coherence in our scheme.     

Ultra-Low Threshold Optical Bistability and Multi-Stability in Dielecrtric Slab Doped with Semiconductor Quantum Well

A scheme for switching of the optical bistability (OB) and multi-stability (OM) in a dielectric slab doped with a three-level ladder-configuration n-doped semiconductor quantum well is simulated. It is shown that the bistable behavior of the system in dielectric slab can be controlled via amplitude or relative phase of applied fields. This optical system may provide some new possibilities for test the switching process.     

Bistable operation of a GaAs-AlGaAs diode laser coupled to an external resonator of narrow spectral bandwidth

The influence of an external dispersive resonator on the emission properties of a double heterostructure semiconductor laser operating at room temperature has been investigated. The proper design of the external resonator (frequency selectivity and efficient back-coupling of the radiation leaving the diode) demonstrates that a laser with optical feedback can show bistability and hysteresis phenomena. The dispersive bistability has its origin in the dependence of the refractive index on carrier density, temperature and optical power. Hysteresis curves have been measured by changing the injection current or by tuning the dispersive element. We have found a threshold in the injection current for the onset of the hysteretic behaviour. Moreover, a theoretical model has been established to explain the essential features of the experimental results. Hysteresis cycles for different experiments have been calculated.     

Effect of Quantum Interference from Incoherent Pumping Field and Spontaneous Emission on Controlling the Optical Bistability and Multi-Stability

Optical bistability (OB) and optical multi-stability (OM) of a four-level Λ-type atomic system with two fold lower levels inside a unidirectional ring cavity is investigated. The effect of quantum interference arising from spontaneous emission and incoherent pumping on OB and OM is discussed. It is found that the threshold of OB and OM can be controlled by quantum interference mechanisms. In addition intensity of coupling field and the rate of an incoherent pumping field on behavior of OB and OM are then discussed.     

Optical bistability and multi-stability via voltage-controlled and the rate of incoherent pump in a quantum dot nanostructure

The optical bistability (OB) and optical multi-stability (OM) in a four-level quantum dot molecule are investigated. The effect of tunnel coupling and the rate of incoherent pump on OB are then discussed. It is found that the OB threshold can be controlled via tunnel coupling and the rate of incoherent pump. We demonstrate that the voltage-controlled detuning can significantly affect the behavior of OB and OM, therefore the OM converts to OB only by the rate of incoherent pump. The results obtained can be used for the development of new types of nanoelectronic devices for realizing switching process.     

Study of thermally induced optical bistability in a twisted nematic liquid crystal

We report the observation and study of optical bistability in the power transmitted by a twisted nematic liquid crystal bounded by crossed dichroic polarizers. A detailed study of the dependence of the phenomenon on the sample initial temperature has been performed. The effect is a good test for a simple theoretical model which describes the isotropic droplet formation in a nematic sample under laser illumination. A good agreement is found between experimental results and theoretical predictions. Applications of the effect to realize temperature sensors are envisaged.