Design of a Dual Wavelength Birefringent Filter.

The simulation of a tunable dual wavelength birefringent filter is presented with the ultimate goal of developing a novel optical in the terahertz (THz) region of the electromagnetic spectrum for medical applications. THz radiation is located in the electromagnetic around 300 μm. For a long time this frequency domain has been named the “THz-gap” due to the lack of sources and detector systems. Here we present a novel alternative for a THz laser source based on the novel birefringent filter presented. The filter is constructed using four stages quartz plates placed at Brewster angle. The design of the filter was done using a zero diving angle to facilitate its construction, and the tunability in the overall response of the filter is achieved by rotating only one of the plates. The filter was design to have a center response around 980 nm with the peak separation of 2.50 nm to 3.75, corresponding to frequency separation between 0.8 THz to 1.2 THz, compatible with broadband laser sources in the 980 nm vicinity. [ABSTRACT FROM AUTHOR]