Simultaneous Raman spectra measurement using power build-up cavity (PBC)

Raman spectroscopy using a simple external Power Build-up Cavity (PBC) pumped with a diode laser was demonstrated. The PBC is very simple configuration consisted of anti- reflection coated low power (10mW, (lambda) equals670nm) laser diode, Graded index (GRIN) lens, and extremely high finesse external cavity, where the beam intensity can reaches up to 100W intracavity beam. Such a high finesse external cavity could optimized parameter attribute to high spectral brightness mostly suitable for a compact Raman light source without any sophisticated temperature and/or current injection control. PBC pumped Raman spectrum was measured by an optical fiber coupled optical multi-channel analyzer (OMA). The Raman signal from intracavity beam was imaged on the optical fiber by two focusing lenses (fequals38mm, 50mm) located in perpendicular to the optical axis. Stokes Raman spectra of N2 and O2 of gas mixture were simultaneously measured with real time operation, approximately.