Stimulated Raman Scattering (SRS) in alpha-AlOOH (Diaspore)

In single crystals of orthorhombic alpha-AlOOH, known also as mineral diaspore, chi((3))-nonlinear lasing by stimulated Raman scattering (SRS) and Raman-induced four-wave mixing (RFWM) is investigated. Picosecond pumping at 1.064 mu m wavelength produces a broadband Stokes and anti-Stokes frequency comb with up to 25 SRS- and RFWM-generated emission lines. All observed Stokes and anti-Stokes lasing components in the visible and near-IR are identified and attributed to a single SRS-promoting vibration mode with omega(SRS) approximate to 445 cm(-1). The first Stokes steady-state Raman gain coefficient in the visible spectral range is estimated to a value not less than 0.36 cm GW(-1).