Terahertz gas laser provides a series of linearly polarized lines with frequencies ranging from 0.25 to 7.5 THz and power from 1 to 100 mW. The linear polarization of any laser line can be converted to circular polarization by inserting a special optical device designed for this purpose. The beam is concentrated by a parabolic mirror to a sample placed in an optical cryostat. The transmitted light is detected by a helium-cooled bolometer.
FIRL-100 FIR/THz gas laser