NARROW-LINEWIDTH PASSBAND FILTER FOR ULTRAVIOLET ROTATIONAL RAMAN IMAGING

We present a narrow-passband spectral filter capable of frequency-reso lved imaging of rotational Raman light scattering with strong spectral rejection of out-of-band Raman, Rayleigh, and Mie scattering. The fil ter is based on mercury-vapor absorption, and subsequent resonant fluo rescence and has a passband of less than 1 cm(-1) It is paired with an injection-seeded, cavity-locked, frequency-tripled Ti:sapphire laser that produces > 30 mJ/pulse of single-mode, tunable light in the vicin ity of 253.7 nm. The laser and filter are combined to spectrally resol ve scattering from individual rotational Raman lines of nitrogen and o xygen. (C) 1997 Optical Society of America.