Grating-Tuned Dual-Wavelength Nile Red Dye Laser

Dual-wavelength operation of grating-tuned dye laser systems was demonstrated in this paper. We used the second harmonic generation of a Q-switched Nd: YAG laser to pump the Nile red solvent (dissolved in ethanol) in the Littrow configuration and the Littman-Metcalf configuration. By rotating the grating 3.6 degrees in the Littrow configuration and the tuning mirror 3.9 degrees in the Littman-Metcalf configuration, we obtained a 72 and 46 nm tuning-range dye laser output, respectively. Meanwhile by parallelly moving the grating in the Littrow configuration and the tuning mirror in the Littman-Metcalf configuration, we achieved the separation of dual wavelength from 0.7 to 5 nm in the former and 1.5 to 4 nm in the latter, which were in the terahertz range and could find applications in the terahertz source after using difference frequency technology. Finally, after considering the laser trajectories in the two configurations, we theoretically analyzed the reasons for overall tuning and separation tuning of dual wavelength. (c) 2019 Optical Society of America