Lasing properties of several near-IR dyes for a nitrogen laser-pumped dye laser with an optical amplifier

The energy per pulse as a function of wavelength was measured for several near-IR dyes (and dye mixtures) spanning the wavelength region from 650 to 950 nm using a 900 kW nitrogen laser (Molectron UV24) and a tunable dye laser-amplifier combination (Molectron DL14). The peak energy per pulse for each dye ranges from a low of 90 μJ at 855 nm (DTTC) to a high of 350 μJ at 702 nm [Oxazine 720P:Rhodamine 610P (1:1)]. Several new near-IR dye mixtures are discussed that make it possible to tune from 660 to 940 nm without having the energy per pulse drop below 50 μJ. Pulse widths (FWHM) for HITC and IR 125 were measured at various wavelengths and were observed to vary by as much as 40 percent over the tuning ranges of the dyes.