Calcium Fluoride (CaF2) has long been used in research applications. It is a cost-effective solution that performs well in controlled environments where humidity, chemical exposure, vibration and high frequency noise can be minimized or eliminated.
The transmission rate characteristics of CaF2 are ideal for higher temperature applications, short and medium wave thermography and for the visual spectrum where transmission rates are over 90%. Long wave transmission rates will vary (typically between 50% and 60%) based on imager sensitivities at different wavelengths.
VPFC infrared windows are specially coated to reduce and delay the transmission loss due to moisture/humidity. However, industrial users are strongly encouraged to investigate the VPFR series of Industrial-Grade Infrared Windows which are specifically designed for stability in harsh industrial environments.