Variable-finesse wideband Fabry-Perot wavemeter for far-infrared and millimeter waves

A high-bandwidth scanning Fabry-Perot wavemeter using polarizing reflectors is developed for far-infrared and millimeter waves. The strip directions of the two striped polarizing reflectors are made slightly different, and the reflectivity finesse is varied according to the relative angle of the two strip directions. By adjusting this angle one obtains the fringes of Fabry-Perot interference for a wide range of far-infrared and millimeter wavelengths. Experimental results show that the wavelength measurement range is approximately 100 to 3000 microm.