Simple cryogenic infrared window

A simple, cheap technique is reported that allows materials with both large and small thermal expansion coefficients to be mounted as windows in low temperature cryostats while at the same time avoiding thermal stresses. The construction may be thermally cycled many times with no change in its properties. It can hold differential pressures of at least 1 atm for a 1‐in.‐diam window. This technique seems to be particularly useful for applications where the use of soft materials cannot be avoided (e.g., ZnSe in the infrared).