DEVELOPMENTS OF THE AMPLIFIED STIMULATED-EMISSION TECHNIQUE FOR SPATIALLY-RESOLVED SPECIES DETECTION IN FLAMES

It is demonstrated that the amplified stimulated emission technique ca n be applied for spatially resolved detection of flame species requiri ng a two-photon excitation process. The approach utilizes two laser be ams of different wavelengths produced by a dual wavelenght package in the dye laser. By wavelength separation through the use of two differe nt doubling crystals fulfilling the phase-matching condition for only one beam at a time, followed by crossing the beams in the flame, a sub stantial increase in spatial resolution is achieved. The technique is demonstrated on ammonia in a jet and on carbon atoms in a welding torc h flame.