Measurement of nonlinear frequency chirp of Q-switched ruby laser

Abstract

The frequency chirp of a Q-switched ruby laser is investigated with two interference experiments: holography of a rotating object and measurement of time coherence. Nonlinearity of the frequency chirp markedly affects both interference experiments for large time differences between the two beams, which enable us to determine the nonlinear frequency chirp, that is, chirp rate and time. A hyperbolic tangent function provides a better approximation of the frequency chirp than the linear function generally used. In this experiment the chirp time was 1.0-1.5 times as long as the half-intensity width of the pulse.

Spiking ruby revisited: self-induced periodic spiking oscillations leading to chaotic state in a Cr:Al2O3 laser with cw 532-nm pumping

“…The optical bistability was demonstrated in a Fabry-Perot cavity containing the pink ruby for the input light nearly resonant to R1 line (694 nm) with the input power level below 20 mW, resulting from a huge nonlinear refractive index [27]. A large amount of frequency chirping was observed in a Q-switched ruby laser operating at 694 nm [28], which would correspond to a resonanceenhanced 𝑛 2 -value on the order of 10 -16 m 2 /W under lasing conditions, in reference to values of various materials measured by the nonlinear transmittance measurement method [29].…”

Self-Induced Spiking Oscillations and Associated Instabilities in a Laser-Diode-Pumped Three-Mode Nd:YVO 4 Laser

“…Indeed, a huge resonance-enhanced nonlinear refractive index of 𝑛 2 = 1.25 × 10 −12 m 2 /W was reported in an experiment based on the differential interferometric technique using an argon ion laser for the absorption band at 514.5 nm [20], which resulted in self-induced superluminal and subluminal group velocity propagation in the pink ruby [21,22]. A large amount of frequency chirping was also observed in a Qswitched ruby laser operating at 694 nm [23], which would correspond to a resonance-enhanced 𝑛 2 -value on the order of 10 -16 m 2 /W under lasing conditions, in reference to values of various materials measured by the nonlinear transmittance measurement method [24]. Here, we examine the Kerr-lens effect based on the anomalous dispersion resulting from the population-density changes caused by high-intensity spikes to provide new insights into self-induced spiking behaviors.…”