Open AccessTerahertz beam steering and variable focusing using programmable diffraction gratings
Author(s) -
Yasuaki Monnai,
Kristian Altmann,
Christian Jansen,
Hartmut Hillmer,
Martín Koch,
Hiroyuki Shinoda
Publication year - 2013
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.21.002347
Subject(s) - terahertz radiation , optics , grating , diffraction grating , diffraction , beam steering , materials science , diffraction efficiency , beam (structure) , terahertz spectroscopy and technology , optoelectronics , physics
We propose a freely programmable THz diffraction grating based on an electrostatically actuated, computer controlled array of metallic cantilevers. Switching between different grating patterns enables tailoring spatio-temporal profiles of the THz waves. By characterizing the device with spatially resolved THz time domain spectroscopy, we demonstrate beam steering for a wide frequency band extending from 0.15 THz to 0.9 THz. The steerable range at 0.3 THz exceeds 40°. Focusing is also demonstrated by programming a chirped grating. The proposed approach could be employed to mimic arbitrary diffraction optics, enabling highly integrated and extremely flexible systems indispensable for THz stand-off imaging and communications.