Multifunctional plasmonic metamaterial absorber in the middle infrared range for polarization detection

Abstract

It is significant to enhance the absorption rate, extend bandwidth and obtain the polarization information of electromagnetic radiation for detection technology. Here, we design and propose the simulation model of broadband and highly polarization-sensitive mid-IR metamaterial absorber by regulating the light field with the plasmonic response. The absorber is based on a simple subwavelength metal grating construction. Its absorption response can cover the 3–5 μm infrared atmospheric window. Detection technology in the mid-IR range has a strong ability to detect objects at high temperatures. In this waveband, the maximum absorption rate can reach more than 98% for TM polarization radiation. In comparison, it is less than 2% for TE polarization radiation, and the extinction ratio of 50 is concurrently achieved. The absorption spectrum can be broadened to the high and low-frequency direction by reasonably adding nanostrips in the unit cell. We also investigate the relationship between incident angle and spectral absorption and clarify the absorption stability of the absorber under oblique incidence. By integrating with the infrared focal plane detector, the device can make the infrared photodetector integrate and develop from a single sensor to multi-dimensional information and promote the development of polarization detector to miniaturization, high efficiency and high integration.