New T-ray source could improve airport security, cancer detection

Left: Schematic of the terahertz-source, which was fabricated on the top of an atomically layered superconducting crystal. The applied current excites the fundamental cavity mode (solid half-wave) on the width w of the mesa, and high-frequency electromagnetic radiation is emitted from the side faces (red waves). Right: Spectra of the radiation emitted from a 100 µm (green), 80 µm (blue) and 60 µm (red) wide mesa. The inset shows the proportionality of the emission frequency and the inverse width, as is expected for a cavity resonance.