Transfer of Raman-Scattered Light from Gases by Fiber Optics

Abstract

In the focus of the argon-ion ring laser of our cw CARS spectrometer, a power of over 100 W is available at 514.5 nm. It has been used here for the excitation of linear Raman spectra of gases. The collected 90° scattering is transferred to the entrance slit of a double monochromator by ordered fiber-optic bundles with slit-like cross sections. The transfer efficiency varies with the slitwidth used; values between 13% and 23% have been achieved. The recorded spectra of nitrogen and air compare favorably with those obtained with conventional extra-cavity single-pass excitation.