Use of high Tc superconductors for far‐infrared Fabry–Perot resonators

Abstract

In this letter we report on the application of high Tc superconductors for fabrication of far‐infrared Fabry–Perot resonators. Thin films of YBa2Cu3O7−δ deposited on MgO substrates by the laser ablation technique were used as reflectors. Two films on two different MgO plates were arranged parallel at a distance determining the lowest order resonance. We demonstrate operation of a resonator in a frequency range (up to about 300 cm−1) in which MgO is transparent at low temperature.