High Extinction Ratio Subwavelength 1D Infrared Polarizer by Nanoimprint Lithography

Indiana University-Purdue University Indianapolis (IUPUI)Infrared (IR) polarizers have been widely used in military and commercial applications. Controlling the polarization of incident light is one of major issues in the detector systems. However, conventional polarimetric IR detectors require series of polarizers and optical components, which increase the volume and weight of the system. In this research, stacked 1-dimensional (1-D) subwavelength grating structures were studied to develop compact size IR polarimetric detector by using surface plasmonic polariton. Experimental parameters were optimized by Finite Difference Time Domain (FDTD) simulation. Effects of gold (Au) grating size, numbers of stacked gratings, and dielectric space height were tested in the FDTD study. The fabrication of grating layers was conducted by using nanoimprint lithography. The samples were characterized by scanning electron microscopy. IR transmissions in transverse magnetic (TM) and transverse electric (TE) modes were measured by Fourier transform infrared spectroscopy (FTIR)