Maurya Somendu, Nyman Markus, Kaivola Matti, Shevchenko Andriy
Opt Express. 2019 Sep 16;27(19):27335-27344. doi: 10.1364/OE.27.027335.
We consider a highly anisotropic metamaterial structure, composed of parallel metal nanostripes, and show that a thin layer of the material can be used as a tunable partial polarizer. The transmittance of the structure for TE-polarized waves depends strongly on the incidence angle, while for TM-polarized waves, it stays high and essentially constant. In particular, using the structure, the degree of polarization of a partially polarized or unpolarized light can be tuned by changing the incidence angle. The TE-wave transmittance drops from, c.a., 1 to 0 when the incidence angle increases by 5 deg only, owing to the presence of an unusual higher-order odd-symmetric TM mode that we have revealed in the structure. The tuning can be made smoother by introducing another layer of a similar metal-nanostripe structure on top of the first one. The new design allows the TE-wave transmittance to decrease gradually towards 0 with the incidence angle increasing from 0 to about 30 deg. Our structures serve as an essential optical component for studies involving partially polarized light.
我们考虑一种由平行金属纳米条纹组成的高度各向异性超材料结构，并表明该材料的薄层可用作可调谐部分偏振器。该结构对TE偏振波的透射率强烈依赖于入射角，而对于TM偏振波，其透射率保持较高且基本恒定。特别地，使用该结构，可以通过改变入射角来调节部分偏振光或非偏振光的偏振度。由于我们在该结构中发现了一种不寻常的高阶奇对称TM模式，当入射角仅增加5度时，TE波透射率从约1降至0。通过在第一层之上引入另一层类似的金属纳米条纹结构，可以使调谐更加平滑。这种新设计允许TE波透射率随着入射角从0增加到约30度而逐渐降至0。我们的结构是涉及部分偏振光研究的重要光学组件。
