Simple generation of tunable near-infrared picosecond dye-laser pulses using spectro-temporal selection

The spectral and temporal processes in broadband pulsed-laser emissions of near-infrared dyes generated from low-Q and short laser cavities have been investigated with a rate equation model extended to a multiwavelength analysis. A very fast spectral evolution is proved, and this leads to the intrinsic presence of a single short pulse on the short-wavelength wing of the broadband IR dye laser spectrum. From the results, the direct generation of picosecond (≈90 ps)infrared dye-laser pulses adjustable in the 700–850 nm spectral range is successfully demonstrated with spectro-temporal selection, in a compact and simple device, using a nitrogen laser (337.1 nm, 8 ns) or a Q-switched ruby laser (694.3 nm, 25 ns) as a pumping source. Received: 6 October 1998 / Revised version: 14 April 1999 / Published online: 11 August 1999