# What materials allow $12\,\mathrm{\mu m}$ LWIR to pass?

What commonly available materials will allow Infrared Radiation with wavelength of $$12\,\mathrm{\mu m}$$ to pass through?

Commonly available is something that can be obtained easily for manufacturing.

Thanks,

• Glass will pass $12\mu m$. – Cinaed Simson May 4 at 8:56

Germanium, Zinc Selenide, Barium Fluoride, Sodium Chloride, and Potassium Bromide all pass 12 $$\mu$$m radiation, and are easily available. Whether or not they are suitable for your application is another question entirely. I think most can be machined by diamond turning, but some, the last two in particular, will become cloudy in humid conditions.