High-spectral-resolution stimulated Rayleigh–Brillouin scattering at 1 μm

We have demonstrated stimulated Rayleigh–Brillouin scattering at a wavelength of 1.064 μm, using an injection-seeded Nd:YAG laser as a pump laser and a tunable diode laser as a probe laser. Spectra with a good signal-to-noise ratio are obtained despite the low probe-beam power and small gain coefficient in the infrared. Stimulated Rayleigh scattering is readily observable in organic and many other liquids because of absorption by the OH and CH overtone or combination bands. The absorption also causes an asymmetry in the stimulated Brillouin peak. A Rayleigh linewidth of 8  MHz is measured with this approach.