磁致伸缩光纤磁光光学双稳态

报道了一种基于磁致伸缩原理实现的全光纤结构磁光光学双稳态装置。与分立元件的磁光双稳系统相比较，该系统的双稳开关功率降低了２～３个数量级，实验结果与理论计算相符。     

磁液磁光双稳特性的研究

本文基于磁液磁致双折射效应,实现了其磁光双稳特性的研究。理论上,建立了其磁光双稳传输模型、进行了计算机模拟,并在此基础上建立了相应的实验分析系统。研究表明:磁液薄膜具有良好的磁光双稳特性,可用作超长波红外波导器件。     

光学空间相干度双稳态

本文首次提出一种由相干度非线性调制得到的新型光学双稳态——空间双稳态及其作用无耦合和有交叉耦合情况下,经γ/υ和υ/ν变换反馈可得到多种形式的双稳态,且给出了几种情况下的稳态特性方程、参数选择区域以及翻转条件等.     

非线性介质光波导中的传输功率和光学双稳态

本文对结构为非线性包层/线性芯层/非线性衬底的非线性介质光波导的传输特性进行了深入的分析,给出了模场分布函数,色散关系和传输功率的一组形式统一的公式,并对其传输功率的光学双稳态特性进行了讨论.     

光反馈电激励半导体光学双稳态的开关时间研究

本文使用电子和光子密度的非线性速率方程及近似处理方法,首次讨论了光反馈电激励半导体光学双稳态的开关时间同系统可调参数之间的关系,从实验上研究了该系统的开关时间特性,提出了改善双稳开关时间的方法。     

力学双稳态—力学回线演示

电磁学中双稳态(磁滞回线)的演示已为众所周知。光学中双稳态(光滞回线)的演示方案及装置也已有报导,但可惜至今尚未见到在国内付诸实施的报导。究其原因大致有二:(1)一般中等学校没有法布里-珀罗标准具,也不具备制作它的条件;     

基于高聚物光诱导激子漂白的无腔光学双稳态

基于已建立的高聚物光诱导激子漂白动力学理论，模拟计算了一类基态非简并高聚物在光激发和弛豫过程中的瞬态无腔光学双稳态．结果表明，基于高聚物的超快激发和弛豫，可获得瞬态饱和吸收型和增强吸收型无腔光学双稳态，其开关时间均在ps和fs量级．随着入射探测光脉冲相对入射泵浦光脉冲延迟时间的增加，无腔光学双稳态可由饱和吸收型向增强吸收型转变，转变的快慢与高聚物光诱导漂白的弛豫的快慢成正比 关键词：     

光栅光学双稳态

本文报道了一种光栅光学双稳态装置.利用改变一对对称光栅间相对位移,实现了对透过光强的周期性调制.将这样的系统作为传输部分,分别用He-Ne激光和普通白光完成了光学双稳实验.实验结果与理论分析相符.     

光学双稳态的输出特性研究

研究了光学双稳系统在处理带噪声周期信号时的一种新的功能,并对输入任意周期小信号时的输出特性进行了研究。     

双反馈光学双稳态

提出了采用双反馈来提高光学双稳系统静态稳定度的方法。理论分析和实验均表明，采用这种方法可命名稳定度获得大幅度提高，非常明显地改善了系统输出的稳定性。     

Controlling bistability by linear augmentation

In many bistable oscillating systems only one of the attractors is desired to possessing certain system performance. We present a method to drive a bistable system to a desired target attractor by annihilating the other one. This shift from bistability to monostability is achieved by augmentation of the nonlinear oscillator with a linear control system. For a proper choice of the control function one of the attractors disappears at a critical coupling strength in an control-induced boundary crisis. This transition from bistability to monostability is demonstrated with two paradigmatic examples, the autonomous Chua oscillator and a neuronal system with a periodic input signal.     

Surface controlled nematic bistability

One discusses phenomenologically the statics and dynamics of surface anchoring of nematic liquid crystals. In statics, for symmetrical situations, one can induce, under the action of an external field, a surface breaking with a bifurcation between two opposite orientations of the director. In dynamics, one shows that the surface director relaxation is intrinsically fast, and accompanied by a transient surface shear flow. In thin cells with planar anchorings, filled by cyanobiphenyl materials which orient normal to the plates under a strong electric field, there are now two effects which couple the relaxation of the surface director: a static one, which favors parallel orientation and a uniform cell texture, and a transient dynamical coupling from the surface flow, which forces π-twisted texture. With suitable electric signals, one can control the surface bifurcations to give at will one of these two bistable textures. Results are presented which show that these mechanisms could lead to a new class of surface controlled, fast nematic bistable displays. Reproduced from ‘Liquid Crystals Today’ (Vol. 8, p. 1–7, 1998) by permission from Taylor and Francis.     

S-shaped current bistability in a bipolar resonant tunneling diode

The bipolar tunneling transport through p–i–n double barrier structures has been studied by means of simultaneous electrical transport measurements and electroluminescence spectroscopy. An “inverted” hysteresis loop is observed at the onset of the first electronic resonance in the current–voltage characteristics with an electrical ON/OFF ratio of more than two orders of magnitude. Relating the different branches of the current–voltage characteristic to the space charges accumulated throughout the structure the inverted hysteresis loop is interpreted in terms of an S-shaped current bistability. The S-shaped current bistability is similar to the current driven negative differential resistivity as known for instance from thyristor action. This analogy between the bipolar double barrier structure with alloyed n-type emitter and the thyristor will be briefly discussed.     

Enhanced bistability with the line-narrowed modes in a nonlinear modulated index Fabry-Perot cavity

We exploit the recently reported line narrowed modes [1] for observation of bistability in a nonlinear Fabry-Perot cavity with intracavity index modulation. We show that the frequency response of the structure exhibits larger bistability loops for the line narrowed modes.     

Investigation on the bistability of linearly chirped nonlinear Bragg gratings

Based on the nonlinear coupled mode theory, by using the reversely recursive transmission matrix method, the switching characteristics of linearly chirped nonlinear Bragg gratings (LC-NLBG) have been investigated numerically. The results show that, introducing spatial chirp in fiber gratings is helpful to widen the bistable wavelength range, and the influence of the chirp on the switching-on threshold and the on-off ratio of the bistable switching are obvious, the chirp-dependent bistability is due to the difference of the axial distribution of forward wave intensity in the gratings.     

Coupler-loss and coupling-coefficient-dependent bistability and instability in a fiber ring resonator

In this paper, we demonstrate the dynamic simulation of light traveling in a fiber ring resonator with a single coupler. Optical nonlinear phenomena including bistability, the Ikeda instability, bifurcation and chaos are studied. The Ikeda instability in ring resonator arises from the ring-cavity lifetime being much longer than the Kerr-effect response time of the fiber. The transmission curves of the bistability and the instability as function of the insertion losses (γ) and the coupling coefficients (κ) of the coupler are derived.     

Pattern formation in the thiourea-iodate-sulfite system: Spatial bistability, waves, and stationary patterns

We present a detailed study of the reaction-diffusion patterns observed in the thiourea-iodate-sulfite (TuIS) reaction, operated in open one-side-fed reactors. Besides spatial bistability and spatio-temporal oscillatory dynamics, this proton autoactivated reaction shows stationary patterns, as a result of two back-to-back Turing bifurcations, in the presence of a low-mobility proton binding agent (sodium polyacrylate). This is the third aqueous solution system to produce stationary patterns and the second to do this through a Turing bifurcation. The stationary pattern forming capacities of the reaction are explored through a systematic design method, which is applicable to other bistable and oscillatory reactions. The spatio-temporal dynamics of this reaction is compared with that of the previous ferrocyanide-iodate-sulfite mixed Landolt system.     

Exploring bistability in rotating Bose-Einstein condensates by a quotient transformation invariant continuation method

We study the discrete nonlinear Schrödinger (DNLS) equations that model rotating Bose-Einstein Condensates (BEC) both analytically and numerically. Due to the difficulties associated with transformation invariant solutions, standard continuation methods may not properly follow the solution curves of the DNLS equations. We propose a quotient transformation invariant continuation method to circumvent this obstacle. We also analyze the bifurcation properties of the primal stalk solution curve corresponding to the DNLS equations for an isotropic trap. In numerical computation, the existence of a bistable region corresponding to the bound states with a 0- or 1-vortex is shown. This finding not only agrees with the physics of the experimental phenomena, but also explains why a 0- or 1-vortex may be observed within a certain region that has an angular velocity. Numerical evidence shows that trap potentials have little effect on the width of the bistable regions. In contrast, intra-component scattering length significantly affects the bistable region.