Discussion about Sapphire or other transparent high thermal conductivity materials.

[wormneurolab]

In the current cooling stage design, we use a sapphire window for both light transmission for bright field illumination and thermal conduction. The thermal conductivity of sapphire is around 40 W/(m • K). Typical glass thermal conductivity is around 1 W/(m • K). Diamond is the best, around 1000 W/(m • K), but...

Sapphire window is not easy to buy, and they can be very expensive depending on the vendor you use.