Questions about Transmission Gratings
The standard AR coating is for the visible region only. It covers 400 to 750nm and is typically 1.5% reflection.
- Soda Lime glass (float): 9×10-6/degreeC
- Annealed Borosilicate (Pyrex): 3×10-6/degreeC
- Zerodur: 0.1×10-6/degreeC
The limit is ±0.5% but most gratings are typically much better.
Dispersion required and efficiency at peak wavelength are often trade-offs. Coarse gratings, for example, generally have higher peak efficiency but lower dispersion.
It is the blaze angle of the grating.