Ultrasonic Control of Laser Performance

摘要

The report describes the work performed on a research program directed toward determining the oscillation characteristics of a laser when the refractive index within the feedback cavity is perturbed by means of acoustic, electric, or magnetic fields. The laser is represented in terms of a system block diagram having forward and feedback transfer functions which can be varied in a periodic manner so as to modulate the output of the quantum device. The modification of a laser's feedback transfer function by an ultrasonic-refraction and by an optical-tunneling shutter has been utilized to gate the laser's output. Experiments are reported which demonstrate that the periodic fluctuation of the refractive index resulting from the propagation of focused ultrasonic energy within a solid state laser medium can be utilized as a Q-spoiler to gate the output of high gain lasers without the introduction of lossy elements into the laser's feedback path. In addition, experiments are reported which reveal an increase in the energy output of a neodymium doped Lanthanum Thorium Borate glass rod when longitudinal acoustical standing waves were propagated down the length of the glass rod. (Author)