Experimental investigation of a light-controlled nonlinear scatterer

Abstract

It is demonstrated that the spectrum of a high-frequency signal reradiated by a nonlinear scatterer can be controlled using optical radiation. The scatterer is a monopole antenna with a nonlinear element (phototransistor). By illuminating the phototransistor, it is possible to change its nonlinear conductance and capacitance and thereby the spectrum of the scattered signal. The low-frequency (LF) modulation of parameters of the nonlinear element caused by the modulated optical radiation results in modulation of the scattered signal both at the base frequency and the combination frequencies produced by the nonlinear conversion. The proposed scatterer can be used as a feederless sensor of the electric field whose output signal can be readily separated from interferences due to the LF modulation.