Title :
Pump–Probe Measurements of the Raman Gain Coefficient in Crystals Using Multi-Longitudinal-Mode Beams
Author :
Sabella, Alexander ; Spence, David J. ; Mildren, Richard P.
Author_Institution :
Defence Sci. & Technol. Group, Edinburgh, SA, Australia
Abstract :
The effect of multi-longitudinal-mode interference on pump-probe Raman gain measurements is studied as the functions of laser linewidth and correlation between the pump and probe temporal structures. For Raman linewidths typical of crystals, correlations that develop between the pump and the probe increase the Raman amplification beyond the ideal single longitudinal mode case, leading to inflated Raman gain coefficient values. We show that the linewidth correction factors used previously are valid only for uncorrelated beams and small gain factors. Taking into account these considerations, a Raman gain coefficient for a diamond of 3.80 ± 0.35 cm/GW is reported at a pump wavelength of 1.864 μm (polarizations parallel to a 〈110〉 crystal axis).
Keywords :
Raman spectra; diamond; laser beams; light interference; light polarisation; optical correlation; optical pumping; optical variables measurement; spectral line breadth; C; Raman amplification; Raman gain coefficient values; crystal axis; diamond; laser linewidth functions; light polarizations; multilongitudinal-mode beams; multilongitudinal-mode interference; optical correlation; pump-probe Raman gain measurements; pump-probe measurements; wavelength 1.864 mum; Correlation; Crystals; Laser beams; Laser excitation; Measurement by laser beam; Probes; Stimulated emission; Diamond; Raman gain; Raman scattering;
Journal_Title :
Quantum Electronics, IEEE Journal of
DOI :
10.1109/JQE.2015.2503404
