An Analytic Description of Light Emission in Sonoluminescence

Light emission in sonoluminescence is shown to be a lasing process with a wide gain bandwidth. Population inversion of the gas molecules inside the bubble is achieved by hydrodynamical pumping. Analytic expressions are derived for the sonoluminescence pulse shape, pulse width, and their codependence on the spectrum and intensity in physically relevant regimes. A detailed comparison with experiments(R. Hiller et al., Phys. Rev. Lett. 80, 1090 (1998); M.J. Moran et al., Phys. Rev. Lett. 80}, 4987 (1998); R. Pecha et al., Phys. Rev. Lett. 81, 717 (1998)) suggests excellent agreement.