This paper describes the design and performance of a cryogenic system for a sapphire Fabry-Perot optical frequency reference cavity. The cryogenic system utilises a single vacuum system, a liquid helium coupled heat exchanger, low mechanical vibration mounting and an axial, bottom-entering optical path. The cryogenic and thermal performances are also described.
Notcutt, M., Taylor, C. T., Mann, A., Gummer, R., & Blair, D. (1996). Cryogenic system for a sapphire Fabry-Perot optical frequency standard. Cryogenics, 36, 13-16. https://doi.org/10.1016/0011-2275(96)80763-6