Generation of High Power 1.54 Micrometers Radiation by Stimulated RamanScattering in Methane (Opwekking van Hoogvermogen 1.54 Micrometers Straling m.b.v. Gestimuleerde Raman Verstrooiing in Methaan)

摘要

We report about experiments with a Nd:YAG laser operating at 1.064 microns whichare carried out to obtain an efficient source of eye-safe 1.54 microns radiation. This conversion is obtained by Stimulated Raman Scattering in methane by applying focussing and a dichroic mirror for feedback. The varied parameters are laser power, pulse repetition rate, gas pressure, gas constitution, beam width and the optical strength of the lenses. With a spherical lens we obtained 61% conversion efficiency with an input of 22 mJ. For a combination of two cylindrical lenses of 100 mm focal length and 200 mJ input a value of 74% is found. At pulse repetition frequencies higher than 5 Hz a degradation of the output takes place. Keywords: Lasers, German language. (js)