Subwavelength antireflective micropyramid structures, designed by rigorous coupled-wave analysis and fabricated by precision micromachining, are used to enhance the terahertz (THz) radiation output of optical rectification in GaP crystal-based emitters. An average 16% increase in the THz radiation power emitted by a 3 mm GaP crystal is experimentally demonstrated using an antireflective micropyramid grating with a period of 60 μm and a base angle of 55.5°. Optimized pyramidal-frustum gratings are shown to operate as highly efficient antireflective structures within an ultrabroadband range of 0.5–5 THz.
© 2013 Optical Society of America
Diffraction and Gratings
Original Manuscript: April 22, 2013
Manuscript Accepted: May 8, 2013
Published: June 5, 2013
Xiaokun Hu, Yanfeng Li, Fengzhou Fang, Xian Li, Jiang Li, Yunhui Chen, Xiaodong Zhang, Lu Chai, Chingyue Wang, Andrey B. Fedotov, and Aleksei M. Zheltikov, "Enhancement of terahertz radiation from GaP emitters by subwavelength antireflective micropyramid structures," Opt. Lett. 38, 2053-2055 (2013)