Inversion Dependent Frequency Shifts in Passively Q-Switched Ruby Laser and Second Harmonic Emission

摘要

Previous experiments have indicated an inversion dependent blue shift in the emission frequency of pulsed (non-Q-Switched) ruby lasers during the emission of a single pulse. The purpose of this work was to study the temporal coherence properties of single mode passively Q-Switched ruby laser emission by using a transient interference detection technique capable of better than 4 nsec resolution. The experiments were carried out using a Young's double pinhole interferometer to interfere the output of the laser with a portion of the same output delayed by a given time period. From the time dependence of the interference pattern phase, in combination with the simultaneously measured time dependence of laser power it was firmly established that an inversion dependent blue shift exists in the emission frequency of a single mode Q-Switched ruby laser. A number of physical mechanisms are discussed which could possibly account for a laser frequency shift. Experiments were also performed to determine the direction and magnitude of any existing frequency shifts in second harmonic emission (at 3472 A). (Author)