Surface relief gratings are well-established elements for high power laser applications, e.g. ultra-short pulse compression. A binary submicron period profile, realized by e-beam lithography and reactive ion beam etching in a dielectric material, is utilized for nearly one-hundred percent diffraction efficiency. Because these gratings are manufactured without any replication techniques, a high wave front accuracy and a low stray light background can be achieved. Spectroscopic applications require additional properties, i.e. a larger spectral bandwidth and Off-Littrow operation. We present new approaches for surface relief gratings realized either via multi-level staircase profiles or exploiting sub-wavelength features. The RVS spectrometer grating in ESA’s GAIA mission is a prominent example where these techniques are already in use. The current contribution focuses on the results achieved during a pre-development performed for the MOONS instrument intended to operate at VLT.

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Torsten Harzendorf, Dirk Michaelis, Thomas Flügel-Paul, Andrea Bianco, Ernesto Oliva, and Uwe Zeitner, "Surface relief gratings manufactured by lithographic means being a candidate for VLT MOONS instrument’s main dispersers," Proc. SPIE 10706, Advances in Optical and Mechanical Technologies for Telescopes and Instrumentation III, 1070621 (Presented at SPIE Astronomical Telescopes + Instrumentation: June 14, 2018; Published: 6 September 2018); https://doi.org/10.1117/12.2313164.