Convex and concave diffraction gratings are required for concentric imaging spectrometer forms. Direct-write electron-beam lithography has proven to be an effective method for fabricating high-efficiency blazed gratings on non-flat substrates. Recently fabricated convex gratings have demonstrated relative efficiency greater than 90%, diffuse scatter and ghosts less than 5x10^-4 of the main diffraction order, and zeroth-order wavefront error less than 1/4-wave at 633 nm. Such gratings can be fabricated on JPL’s JEOL JBX-9300FS electron-beam lithography system with a writing speed of approximately 1 to 2 cm² per hour. The technique was recently used to fabricate flight-qualified gratings for the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) instrument that is scheduled to fly on the NASA Mars Reconnaissance Orbiter in 2005.

Date Published: 3 November 2003
PDF: 12 pages
Proc. SPIE 5173, Current Developments in Lens Design and Optical Engineering IV, 51730E (3 November 2003); doi: 10.1117/12.510204

Published in SPIE Proceedings Vol. 5173:
Current Developments in Lens Design and Optical Engineering IV
Pantazis Z. Mouroulis; Warren J. Smith; R. Barry Johnson, Editor(s)