We report on stacked high-contrast grating reflectors with virtually angular independent reflectance for transverse-magnetic polarized light. The investigated structure consists of two-layer pairs of amorphous silicon and silicondioxide that are designed for a wavelengths of 1550 nm. The large angular tolerance results from coupling of the two involved silicon gratings and is achieved if the modal fields in the reflectors are matched. With this approach, a reflectance of more than 96% in the entire angular spectrum is feasible. Experimentally we demonstrate a reflectance of more than 98% for incidence angles up to 60° and more than 90% up to 80°.
© 2013 Optical Society of America
Diffraction and Gratings
Original Manuscript: June 17, 2013
Revised Manuscript: July 16, 2013
Manuscript Accepted: July 31, 2013
Published: August 26, 2013
Stefanie Kroker, Thomas Käsebier, Ernst-Bernhard Kley, and Andreas Tünnermann, "Coupled grating reflectors with highly angular tolerant reflectance," Opt. Lett. 38, 3336-3339 (2013)