Laser Q-switching by organic solvents

Abstract

The role of the solvent in the passive Q-switching of lasers by solutions of organic dyes has been examined in detail. It was found that several pure organic solvents could themselves partially Q-switch the laser, in the absence of the dye. This behaviour was observed for both ruby and neodymium : glass lasers. Pulse-widths as short as 20 nsec were occasionally recorded. Peak powers up to 2 MW have been observed using 1-chloronaphthalene to switch a ruby laser. It is proposed that Q-switching arises from an enhancement of reflectivity of the liquid, during the evolution of the laser pulse, through the formation of a periodic refractive index modulation in the liquid by the action of standing waves.

Pulse stretching of Q-switched lasers

“…Recently it has been demonstrated that pure organic solvents are able to cause pulse sharpening of a spiking laser by the formation of a stationary periodic modulation of the refractive index [15]. It was reported in that experiment that no pulse sharpening was observed when carbon disulphide was placed in the resonator of a ruby laser.…”