We propose a spatial modulator for terahertz waves based on light induced electron plasma in photo-active semiconductors. A two-dimensional array of computer controlled light is used to create free carries in bulk silicon, which results in a spatial modulation of the transmission at terahertz frequencies. This method not only exhibits a remarkable modulation depth over a broad frequency range but also allows for an optically controlled beam steering of terahertz waves by inducing virtual grating structures. In addition, we analyze the possibility of all-optically controlled terahertz imaging.
© 2012 Optical Society of America
Fluorescent Luminescent Materials
Original Manuscript: December 16, 2011
Manuscript Accepted: January 30, 2012
Published: April 13, 2012
Stefan Busch, Benedikt Scherger, Maik Scheller, and Martin Koch, "Optically controlled terahertz beam steering and imaging," Opt. Lett. 37, 1391-1393 (2012)