Design and Performances of a Dry Table-Top Optical Cryostat at 2K

Abstract We have developed a versatile cryogenic platform for research in optics. The optical cryostat offers an experimental volume of 100 x 100 x 100 mm with up to five 2-inches optical accesses. The cold plate is cooled to a temperature below 2 K with more than 50 mW power available. The cryogenic system is based on a two-stages 4 Kelvin Pulse Tube (PT410RM) and a 2 K helium Joule-Thomson refrigerator. The Pulse-Tube cold head is located in a remote ‘cold box’ connected to the cryostat by a cryogenic line in order to minimize the occupation on the optical table. The thermal coupling is made by two cooling loops, coupling the two stages of the PT with a radiative shield (50 K) and the cold plate (2 K). This solution allows a distance of a few meters between the cryostat and the ‘coldbox’ and limits the vibrations induced by the cryocooler on the experimental plate, which are generally very detrimental in optics.