Transient input of an electromagnetic wave into an open waveguide coated with nonstationary plasma film

Abstract

A technique to input an electromagnetic wave into an open planar waveguiding structure is presented. That is, we propose to coat the waveguide with a thin semiconductor film whose free electron density is controlled by laser pulses. The transient processes which follow the electron density shift in the coating film give rise to the effective coupling between the incident electromagnetic wave and local modes of the waveguiding structure and consequently lead to the creation of the guided modes. We analyze frequencies and amplitudes of the excited guided waves as well as characteristics of the transient radiation from the coating film. Due to the relative simplicity, small size, and as a result fast temporal response, the proposed scheme may find application as a part of integrated circuits for the submillimeter wave range.