Photogalvanic self-pulsing of electro-wetting of LC droplet on LN-crystal

Photorefractive Photonics 2017

Kukhtarev, N.^1 ; Kukhtareva, T.^1 ; Geng, J.^2 ; Zhang, X.Z.^2 ; Xu, J.J.^2

Phys. Dep., Alabama A and M University, United States^1

MOE Key Laboratory of Weak-Light Nonlinear Photonics, TEDA Institute of Applied Physics, School of Physics, Nankai University, Tianjin

300457, China^2

关键词: Developed model;    Discharge resistance;    Electro wetting;    External influences;    Microhollow cathode discharges;    Periodic response;    Phase-space plot;    Pyroelectric effect;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/867/1/012036/pdf
DOI  :  10.1088/1742-6596/867/1/012036

来源: IOP

【 摘 要 】

Photogalvanic current photoinduced by CW laser illumination of Fe-doped LN reveals quasi-periodic pulsing due to microplasmas discharges. This transformation of constant external influence into periodic response is interesting as example of self-excited systems, resembling pulsations of biological systems (including heart beats). Microplasmas is also interesting for potential applications in various fields, such as surface treatment, sterilization, water splitting, light sources, micro jets. Self-pulsing regime of microplasmas discharges in microhollow cathode discharges was observed and modeled in plasmas physics. In this paper, we analyze self-pulsing of photogalvanic current visualized by dynamic electrowetting in a simple LC-cell, formed by a nematic LC droplet placed on Fe-doped LN crystal. We have developed model of self-pulsing regime based on nonlinear discharge resistance. Experimental phase-space plot may be used to find parameters of the nonlinear discharge resistance. In the dynamic modeling contributions from both photogalvanic and pyroelectric effect are included. The analysis of dynamic regime reveals that a current pulse (in microsecond range) have asymmetric shape with extremely sharp rise with longer decay time. These self-pulsations are visualized by reflection of laser light from a LC droplet placed on LN-crystal. Reflected interference patterned was modulated by the dynamic electro-wetting effect.