IMPROVED CIRCULAR POLARIZER FOR FAR-INFRARED LIGHTPIPE SYSTEMS

We present an improved design for far-infrared (FIR) circular polarize rs used in a lightpipe transmission system for magneto-optical experim ents. A peak efficiency of nearly 100% is achieved for FIR laser radia tion by reducing the multiple reflections within the polarizer system, as well as scattering from the walls of the lightpipe. Broadband low- resolution measurements are less susceptible to errors due to multiple reflections, but incorporation of these improvements is still found t o reduce systematic errors due to the reflection from the sample. Also , we have measured the low temperature index of refraction of quartz a nd find significant disagreement with published values for frequencies below 100 cm(-1). (C) 1995 American Institute of Physics.