Far-Infrared Radiation Modulators Using High-Tc Superconductors

The potential of using high-Tc superconductors as intensity modulators for far-infrared radiation is investigated in this work. Reflectance and transmittance for several design structures are computed using the published optical constants of the superconductor YBa2Cu3O7 and substrate materials. Notable differences in the reflectance and transmittance between the superconducting state and the normal state are illustrated. The best results are obtained based on the reflectance of thin films (10 nm–50 nm thick) on thin substrates (less than 100 μm thick) and for radiation incident on the substrate. This study demonstrates that high-Tc superconductive thin films can be used to build far-infrared radiation modulators. Future experimental study is recommended in order to materialize this promising thermo-optical device.