CHARACTERISTICS OF 1,1',3,3,3',3'-HEXAMETHYLINDOTRICARBO-CYANINE IODIDE AS A TUNABLE DYE-LASER IN THE NEAR-INFRARED

We describe the lasing characteristics of a 1,1',3,3,3',3'-hexamethylindotricarbocyanine iodide infrared dye laser. The absorption spectrum of the dye dissolved in ethanol has a large peak centered at 744 nm. The fluorescence exhibits a Stokes shift of approximately 36 nm with a lifetime of 1.7 +/- 0.3 ns. For dye laser pumping at 587 nm the laser threshold was 0.3 mJ, and the slope efficiency was 22% at the central lasing wavelength of 807 nm. The effect of various loss mechanisms is also discussed.