Assessment of a fast electro-optical shutter for 1D spontaneous Raman scattering in flames

In this study, a fast electro-optical shutter composed of a large aperture Pockels cell placed within two crossed polarizers is assessed as optical gating of full-frame back-illuminated CCD camera for single-shot 1D Raman multispecies measurements in flames. The spatial homogeneity of the active response of the Pockels cell crystal is firstly checked with a laser beam. The radial efficiency of the shutter to transmit the weak Raman light is evaluated and the limitations of the setup for 1D measurements are analyzed using an optical magnification. Tests performed in methane-air flames show that the Pockels cell shutter with hundreds of nanosecond gate duration can reduce up to 500:1 the background luminescence leading to up to 10 times of enhancement in the signal-to-noise ratios for Raman-active species.