双层等折射率浮雕结构共振布儒斯特滤光片的泄漏模特性

通过调整光栅的填充系数,获得具有均质层和光栅层等效折射率相等的表面浮雕结构共振布儒斯特滤光片.深入研究了这类滤光片的泄漏模特性,并讨论光栅参数和入射条件的变化对滤光片共振特性的影响.研究表明:入射角的改变对滤光片泄漏模特性的影响不明显,但填充系数、均质层厚度以及基底折射率的改变对滤光片泄漏模特性影响很大.当填充系数f→1和f＜0.6时,以及当基底折射率接近波导层折射率(n→1.63)时,导模共振效应趋于消失.此外,随着均质层厚度的不断增大,多模共振效应将被激发,从而在一定的波长或入射角范围内导致多个泄漏模共振效应的产生.

Leaky-mode characteristics of double-layer surface-relief resonant Brewster filters with equal refractive index

The double-layer surface-relief resonant Brewster filters consisting of a homogenous layer and a grating layer wim equal refractive index are obtained by adjusting the gradng filling factor,and leaky-mode mechanisms of these types of filters are investigated.The main resonance features observed under variation of the filter parameters and incident angle are discussed.It is shown that changing the incidence angle has little effect on the leaky-mode characteristics,but varying the grating tilling factor,the homogeneous layer thickness and substrate refractive index can be significant.As the grating filling factor f→1 and f＜0.6,and as the refractive index of the substrate approaches the refractive index of the waveguide layer(ns→1.63),guided-mode resonance effect will vanish.In addition,as the homogenous layer thickness increases,multiple resonances may be arisen that yield several peaks within a certain wavelength or angular range,exhibiting the unique signature of multiple leaky-mode resonances.