Reflection-reduced encapsulated transmission grating.

We present the design and realization of a highly dispersive dielectric transmission grating with 97.0% diffraction efficiency. This grating is embedded in fused silica, which allows for an efficient suppression of any reflection losses. It is very easy to handle and clean, and its monolithic layout gives rise to high resistance against laser-induced damage and long-term stability comparable to conventional fused silica components.