Classical phase space revealed by coherent light

We study the far-field characteristics of oval-resonator laser diodes made of an GaAs/Al(x)Ga(1-x)As quantum well. The resonator shapes are various oval geometries, thereby probing chaotic and mixed classical dynamics. The far-field pattern shows a pronounced fine structure that strongly depends on the cavity shape. Comparing the experimental data with ray-model simulations for a Fresnel billiard yields convincing agreement for all geometries and reveals the importance of the underlying classical phase space for the lasing characteristics.     

Acoustic emission of single laser-produced cavitation bubbles and their dynamics

Cavitation bubble dynamics is investigated by the method of optic cavitation, i.e. the formation of single cavities in liquids by light. From the sound waves radiated upon collapse the pressure-time curve is obtained. Maximum bubble size and shock wave amplitudes are evaluated and an energy balance is considered. Numerical calculations with a modified Gilmore model taking into account the mass loss of the cavity can explain the rapid damping of the bubble oscillation observed in the experiments.