无偏压光伏晶体中的非相干耦合亮暗孤子对及其传输特性  

Incoherently Coupled Bright-Dark Soliton Pairs and Their Propagation Properties in Unbiased Photovoltaic Crystals

作　　者：彭小兰[1] 周亚民[2] 王红成[1] 

机构地区：[1]东莞理工学院电子工程学院,广东东莞523808 [2]东莞理工学院化学与环境工程学院,广东东莞523808

出　　处：《光学学报》2011年第6期200-204,共5页Acta Optica Sinica

基　　金：广东省高校优秀青年创新人才培养计划项目(LYM10124);东莞市科技计划(200910814038)资助课题

摘　　要：理论研究了均匀照明的无偏压光伏晶体中非相干耦合亮暗光伏孤子对的存在性。发现在共同的光伏光折变效应作用下,具有相同偏振和波长但彼此互不相干的两光束可以形成非相干耦合亮暗光伏孤子对。推导了亮、暗光场分量及其半峰全宽(FWHM)的表达式,并以Cu:KNSBN为例讨论了光强分布特性及半峰全宽与孤子光强的变化关系。结果表明,在形成非相干耦合亮暗孤子对时,暗孤子FWHM要比亮孤子FWHM小得多,从而对折射率改变的贡献较小。并用数值模拟的方法研究了其传播特性,发现非相干耦合亮暗孤子对可以在光伏晶体中稳定传播。当暗孤子光束不存在时,亮孤子光束仍能在晶体中呈呼吸状传播;然而,当亮孤子光束不存在时,暗孤子光束迅速塌陷。A theory is presented to investigate the existence of incoherently coupled bright-dark photovoltaic soliton pairs in an unbiased photovoltaic crystal with uniform illumination. It is found that with the same photovoltaic photorefractive effect, the two optical beams with the same polarization and wavelength but which are mutually incoherent can form incoherently coupled bright-dark photovoltaic soliton pairs. The expression forms of optical field and the full-width at half-maximum （FWHM） of the bright and dark components are deduced. Taking Cu.＂ KNSBN for example, the variation relations between the intensity profile and FWHM and the soliton intensity is discussed. The investigation results show that when incoherently coupled bright-dark soliton pairs form, the FWHM of the dark soliton is smaller than that of the bright soliton. Therefore, it contributes little to the refractive-index change. The propagation properties are also investigated by numerical method. It is found that incoherently coupled bright-dark photovoltaic soliton pairs can propagate stably in photovoltaic crystals. When the dark soliton beam is absent, the bright soliton can still propagate in the crystal with breathing shape. When the bright soliton beam is absent, however, the dark soliton beam collapses quickly.

关 键 词：非线性光学 光学孤子 非相干耦合孤子对 光伏孤子 

分 类 号：O437[机械工程—光学工程]