Raman-lasing dynamics in split-mode microresonators

We study the dynamics of stimulated Raman scattering in high-Q split-mode microresonators. It is found that Raman lasing preferentially occurs in only one of the two competing split modes, and can therefore be beat-note free. Sweeping the pump wavelength causes the intracavity field pattern of the pump light to rotate, which makes the Raman laser hop between the two split modes. During these hops, both modes lase simultaneously, producing a beat note in the output Raman power. By studying this beat note, we demonstrate that the mode splitting is strongly affected by the Raman intensities in the two modes via the optical Kerr effect.