NOISE IN SINGLE-SHOT BROAD-BAND COHERENT ANTI-STOKES-RAMAN SPECTROSCOPY THAT EMPLOYS A MODELESS DYE-LASER

The noise in single-shot coherent anti-Stokes Raman (CARS) spectroscop y that employs a broadband modeless dye laser (MDL) is examined and th e results are compared with those of a conventional dye laser. The noi se of the dye-laser, the nonresonant CARS, and the resonant N-2 CARS s ignals are determined. The use of a MDL is shown to result in substant ially reduced CARS noise when the CARS signal is generated with a sing le-mode pump laser, but only a marginal reduction of noise is observed with a multimode pump source The noise measurements are compared with theoretical predictions that are based on models that assume modes of random amplitudes and phases in the multimode laser sources. The comb ination of a MDL and a single-mode pump laser is shown to increase the precision of single-shot N-2 CARS temperature measurements.