Design of Switchable SHG and THG using Metasurface-based Frequency Mixing System

Abstract

<p>In this letter, we propose a nonlinear reflective metasurface-based frequency mixing system able to perform second-harmonic generation (SHG) and third-harmonic generation (THG). The metasurface consists of a planar bidimensional alignment of unit-cells, each of which encompasses a receiving element at fundamental frequency, and two transmitting elements operating at double and triple the fundamental frequency, respectively. The TX/RX elements within each unit-cell are connected via a microwave network to a RF mixing circuit that performs the conversion, assisted by an RF amplifier that improves the overall conversion efficiency. Efficient switchable SHG and THG frequency conversions are demonstrated by both full-wave simulations and experiments. For the input fundamental frequency of 3 GHz, the conversion efficiencies for SHG and THG are 55.5% and 42.6%, respectively.</p>