Production of radiation at frequencies of preselected absorbing resonances and methods using same

TLDR: In this paper, the regeneration characteristic of the laser oscillation can be determined by a peak in the reflected or transmitted wave produced by the cooperation of the optical interference system and the absorption medium.

Abstract: Radiation at the frequency of a preselected absorbing resonance is produced by use of split and recombined interfering optical paths, arranged to produce near white light interference effects, and a preselected absorption medium disposed in one path of the interfering configuration. By association of this configuration with a laser oscillator, the regeneration characteristic of the laser oscillation can be determined by a peak in the reflected or transmitted wave produced by the cooperation of the optical interference system and the absorption medium. Use with standing wave, ring, and gain-switched transient lasers all can produce radiation essentially confined to the narrow absorption profile of a selected gas. Improved methods of laser chemistry and remote and close range gas detection are made possible by the new system. The system is also useful as an extremely narrow filter for broader band light sources, or as an optical element for other purposes, such as for establishing high Q response for optical resonators of the standing wave or traveling wave, ring type.