Transport of very-high-frequency phonons generated by metallic point contacts in ruby

Abstract

With a novel technique point contacts are used for the generation of very-high-frequency phonons in ruby. In an optical experiment selective for near-zone-boundary phonons, the injected phonons are observed by the R2 fluorescence from a small zone prepared by pulsed optical pumping at distances up to 0.6 mm from the contact. In a time of flight experiment phonons injected in Al2O3 are detected in a broad band with a superconducting tin film.