Self-Sustained Laser Pulsation in Active Optomechanical Devices

We developed a model for an active optomechanical cavity embedding a semiconductor optical gain medium in the presence of dispersive and dissipative optomechanical couplings. Radiation pressure drives the mechanical oscillation and the back-action occurs due to the mechanical modulation of the cavity loss rate. Our numerical analysis utilizing this model shows that, even in a wideband gain material, such mechanism couples the mechanical vibration with the laser relaxation oscillation, enabling an effect of self-pulsed laser emission. In order to investigate this effect, we propose a bullseye-shaped device with high confinement of both the optical and the mechanical modes at the edge of a disk combined with a dissipative structure in its vicinity. The dispersive interaction is promoted by the strong photoelastic effect while the dissipative mechanism is governed by the boundary motion mechanism, enhanced by near-field interaction with the absorptive structure. This hybrid optomechanical device is shown to lead sufficient coupling for the experimental demonstration of the self-pulsed emission.