Wavelength Tunable Random Laser

Abstract

Continuously tunable random laser basing on rhodamine 6G was achieved. Wavelength tuning was implemented by wedge-shaped sample shift relatively to the pump beam. The physical base of the tuning method is gain band shift caused by reabsorption. We ascertained that two medium thickness ranges of significantly different tune efficiency exist. The lasing characteristics of the laser were investigated depending on active medium and pump beam parameters. The feedback formation mechanisms in the random lasers of different thickness were analyzed.

Tuning random lasers by engineered absorption

“…6,7 However, in the field of random lasing [8][9][10][11] both absorption and multiple scattering of light are essential ingredients. 8,[14][15][16] In a convincing series of recent experiments, Gottardo et al 17 have shown that Mie resonances can shift the peak wavelength of a random laser by a few line widths. The gain curve of the emission molecules is the main mode selection mechanism in a random laser.…”