Electrical and thermal control of Fabry-P\'{e}rot cavities mediated by Casimir forces

Abstract

Dynamic tuning of optical cavities is highly desired in many photonic systems. Here, we show that Fabry-P\'{e}rot(FP) cavities can be actively controlled by the Casimir force. The optical FP cavities consist of a gold nanoplate confronted to an electrical-connecting multi-layer substrate in a liquid environment. The gold nanoplate can be stably suspended due to the balance of repulsive and attractive Casimir forces. Moreover, the suspension distance are modulated strongly by the electric gating or temperature of the system. As a result, we could shift the resonant wavelengthes of the cavities with tens of nanometers at optical frequencies. Finally, we analyze the influence of Brownian motion on the equilibrium distances. Due to the high Q-factor of the FP cavities, our proposed system offers a remarkable platform to experimentally investigate the thermal Casimir effect at sub-micrometer separations