Evolution of emission mechanism in deformed microcavities

We report experimental study on the evolution of the emission mechanism by using a phase-space imaging technique based on the local angular momentum conservation in emission process in a chaotic optical microcavity as the cavity deformation corresponding to nonintegrability increases. In the regime of weak deformation, we could image the output beam being emitted tangentially from a location at a certain distance away from the cavity boundary, indicating an evanescent tunneling emission. As the deformation increases further, the location of emission approaches the cavity boundary and the directionality starts to deviate from the tangential direction due to a refractive emission via chaos-assisted tunneling. Here is reported the construction of the internal phase space associated with the modes involved in the tunneling emission of light in the classical mixed phase space where regular and chaotic dynamics coexist.