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    Abstract:
    We studied two types of bistable liquid crystal devices that can be operated in the memory mode as well as in the dynamic mode. One of them is a pixel-isolated twist-splay nematic LC cell that has two stable states of π- twist and splay. Polymer walls are formed at pixel boundaries by anisotropic phase separation between nematic liquid crystals and reactive mesogens. Operation in the memory mode can be achieved through bistable switching between the splay and π-twisted states. The other one is a bistable twisted-nematic mode that has two stable states of -π/2 and +π/2 twist. Three-terminal electrodes are used to apply both vertical and in-plane electric field to both devices. The proposed bistable modes has an infinite memory time and the fast transition time compared to other bistable liquid crystal modes.
    Keywords:
    Bistability
    Optical Bistability
    Switching time
    We propose a bistable liquid crystal mode based on switching of the twist direction in a conventional π/2-twisted nematic cell. Switching between the −π/2 and +π/2 twist states can be performed by applying vertical and/or in-plane electric fields. The proposed bistable mode has an infinite memory time because the two stable twist states have the same elastic free energy.
    Bistability
    Biaxial nematic
    Citations (14)
    When describing the phenomenon of bistability of optical response of an ultra thin layer consisting of two-level atoms it is important to take into account the local field correction. The account of the correction results in the improvement of existence conditions of bistability. One more bistable region is formed starting with certain value of local field parameter. Both effects are induced by the dynamical frequency shift.
    Bistability
    Optical Bistability
    Local field
    Value (mathematics)
    Citations (0)
    Bistability
    Optical Bistability
    Hysteresis
    Overshoot (microwave communication)
    Switching time
    Theoretical investigations on commanding the bistability and self-pulsation characteristics of two-segment bistable semiconductor laser diode (TBLD) using delayed optoelectronic feedback have been carried out in this paper. The effects of feedback gain and delayed time have been simulated numerically based on the rate equations. The results show that the stable region of TBLD varies periodically with delayed time, the bistable region shrinks with the increase of delayed time, stability can be enhanced for certain values of delayed time, and instability can be reached easily for negative delayed optoelectronic feedback. These conclusions establish the theoretical foundation to optimize and control the TBLD and may have potential applications in bistable switching and self-pulsation generation.
    Bistability
    Optical Bistability
    Laser diode
    Rate equation
    Citations (8)
    Experimental results on bistable operation of coupled cavity semiconductor lasers are presented. The light level at the upper and lower states can be controlled by varying the injection current. A model calculation of the coupled cavity laser system shows that the bistability is due to nonlinearities associated with above threshold gain saturation. Our results show that a coupled cavity laser can exhibit bistability at all temperatures and, in addition, the size of the ‘‘hysteresis loop’’ can be easily controlled by varying the injection current. These results are significant for a practical bistable optical device.
    Bistability
    Optical Bistability
    Hysteresis
    Saturation (graph theory)
    Semiconductor optical gain
    Citations (26)
    We report the experimental observation of optical bistable switching in a combined distributed-feedback/Fabry–Perot structure. The sample had a high switching contrast with almost zero reflectivity in the on-state. A turnoff time as short as 4 ns was measured. The threshold power for bistability was about 2 mW. Bistable switching with the memory effect and a potential application for all-optical signal regeneration were demonstrated.
    Bistability
    Optical Bistability
    SIGNAL (programming language)
    Switching time
    Citations (31)
    Abstract The difference between equilibrium and switching d/p ratio of Bistable Twist Nematic (BTN) liquid crystal display was first showed by computer simulation. It clearly indicates that the optimized d/p ratio has to be determined by the switching rather than equilibrium d/p ratio. The considerations of optimized BTN design is discussed.
    Bistability
    Aspect ratio (aeronautics)
    Citations (0)
    Optical bistable behaviour of nematic liquid crystals in Fabry-Perot cavity has been discussed. The normal and abnormal bistable loops were also discussed. Considering thermal conductivity in F-P cavity, a theory to get very low critical switching power optical bistability was developed.
    Bistability
    Optical Bistability
    Citations (0)