Method for polarizing terahertz electromagnetic wave using polarizer, and polarizer

Abstract

A method for polarizing an electromagnetic wave having a frequency of not less than 0.1 THz and not more than 0.8 THz using a polarizer includes steps (a) and (b). The step (a) includes preparing the polarizer. The polarizer includes: a sapphire single crystalline layer; and a CaxCoO2 crystalline layer. The CaxCoO2 crystalline layer is stacked on the sapphire single crystalline layer, a surface of the CaxCoO2 crystalline layer has a (100) plane orientation and the CaxCoO2 crystalline layer has a thickness of not less than 2 micrometers and not more than 20 micrometers. The step (b) includes irradiating the polarizer with the electromagnetic wave having a frequency of not less than 0.1 THz and not more than 0.8 THz to output an output wave having only a component parallel to a c-axis direction of the sapphire single crystalline layer.

Dependencies are inferred from the claim text.