  We study the far field characteristics of oval-resonator laser diodes made of
an AlGaAs/GaAs 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.

Optics;Mesoscale and Nanoscale Physics;Chaotic Dynamics