Wide-angle, broadband plate polarizer in Terahertz frequency region

摘要

In this paper, a plate polarizer for use in the terahertz (THz) frequency region (0.10 THz to 0.15 THz) has been suggested. The polarizer which is effective over a wide range of angles of the incident light (angular field = 16 degrees), is composed of thin film layers of silicon and air arranged alternately to form a stack. Here we show that the polarizer has a high performance in transmission, with maximum and minimum values of the degree of polarization given by 0.9999 and 0.9963 respectively. The polarizer has some advantages over the wide angle cube polarizers investigated earlier. Firstly, in the former, the total number of thin film layers is eleven, whereas in the latter, a larger number of thin film layers are cemented between the two prisms constituting a glass cube. The fabrication of cube polarizers is therefore an expensive procedure. Secondly, prisms exhibit stress related birefringence that changes with temperature and causes problems in imaging projectors. The proposed polarizer is free from such effects.