A beam-steering device has been a key element for various sensing and imaging applications. We proposed a novel beam steering device based on a Bragg reflector waveguide. A steering angle of over 60 degrees and a number of resolution points over 1,000 can be expected for a few mm long device with a low loss high-contrast Bragg reflector waveguide. One-? thick core is sandwiched by two high-contrast quarter wavelength stack mirrors. A slow-light mode can propagate laterally in such a structure with a low propagation loss thanks to high-contrast DBRs. We could see a large angular dispersion of over 1°/nm for radiated light from the surface. Thanks to the large angular dispersion, we are able to realize beam-steering of the radiated light by tuning the wavelength of incident light. We could obtain a continuous steering angle of more than 60° by wavelength tuning of 40nm. The divergence angle is below 0.04° for all wavelengths. Considering the steering range and sharp beam divergence, we successfully achieved a number of resolution points of over 1,000. It is the highest number among all other beam steering devices without a mechanical scanner. We will discuss super-high resolution beam steering from an ultra-low loss Bragg reflector waveguide with high-contrast metastructures. Also, high contrast sub-wavelength grating offers additional freedom to control the inplane phase and reflectivity in Bragg reflector waveguides, which may enable us to control the far-field pattern profile for higher resolutions.

Date Published: 15 March 2013
PDF: 10 pages
Proc. SPIE 8633, High Contrast Metastructures II, 86330E (15 March 2013); doi: 10.1117/12.2007468

Published in SPIE Proceedings Vol. 8633:
High Contrast Metastructures II
Connie J. Chang-Hasnain; Fumio Koyama; Alan Eli Willner; Weimin Zhou, Editor(s)