Terahertz spatial-shift modulation by photo-excitation of polymer/silicon hybrid structures

A spatial shift of the terahertz wave reflected from a polymer/silicon hybrid structures was efficiently modulated by an external continuous wave laser. The intensity and mode of the terahertz reflected wave field change with period depending on the incidence angle of the terahertz wave. This dependence arises from the Fabry-Perot effect and matches the theoretical result. Compared with pure Si, larger spatial shifts can be obtained for the reflected terahertz wave from the MEH-PPV/Si sample in the single mode and multi-mode settings with 510 μm and 1190 μm attained, respectively, using the external laser. The results demonstrate what differentiates traditional intensity modulator is an active functioning terahertz spatial-shift modulator by photo-excitation of polymer/silicon hybrid structures.