Optical bistability and stationary patterns in photonic-crystal vertical-cavity surface-emitting lasers

We report the experimental observation of optical bistability and coherent transverse pattern formation in optically injected, photonic-crystal vertical-cavity surface-emitting lasers, electrically biased below threshold. For injected frequency blueshifted with respect to the cavity resonance, the system exhibits optical bistability and the injected uniform plane-wave breaks up, giving rise to honeycomb- and rolls-like transverse patterns. By comparison with numerical simulations we associate the observed phenomena with the onset of a modulational instability, and discuss the application of this device as an optical memory based on the cavity soliton concept.