Extended Malus' Law with THz metallic metamaterials for sensitive detection with giant tunable quality factor

TL;DR

This paper extends Malus' Law for terahertz metallic metamaterials, demonstrating highly sensitive, tunable transmission responses suitable for precise sensing and material characterization.

Contribution

It introduces an analytical model of a polarizer-analyzer setup in the terahertz regime, revealing a modified Malus' Law influenced by multiple reflections and tunable parameters.

Findings

Transmission response can be controlled by polarizer-analyzer distance

The setup achieves detection of refractive index changes as small as 10^-5

The model enables high-precision terahertz sensing applications

Abstract

We study a polarizer-analyzer mounting for the terahertz regime with perfectly conducting metallic polarizers made of a periodic subwavelength pattern. We analytically investigate the influence on the transmission response of the multiple reflections which occur between polarizer and analyzer with a renewed Jones formalism. We demonstrate that this interaction leads to a modified transmission response: the extended Malus' Law. In addition, we show that the transmission response can be controlled by the distance between polarizer and analyzer. For particular set-ups, the mounting exhibits extremely sensitive transmission responses. This interesting feature can be employed for high precision sensing and characterization applications. We specifically propose a general design for measuring electro-optical response of materials in the terahertz domain allowing detection of refractive index variations as small as $10^{-5}$.