Optical Vortices Crystals: Spontaneous Generation in Nonlinear Semiconductor Microcavities
J. Scheuer,
M. Orenstein
Broad-area, vertical-cavity surface-emitting lasers
were shown to switch their emission mode from the regular single or
multilobed light fields to exhibit complex arrays of "dark beams."
Examination of these dark spot arrays revealed that they consist of
multiple, closely packed optical vortices: optical fields that have
phase singularities and show increased complexity as the injection
current level is raised. Contrary to their complex appearance, most of these light distributions are not the result of a multimode
(multiple-frequency) operation but exhibit single-frequency
characteristics. The dark beam patterns can be described as emanating
from a spontaneous process of transverse mode locking of nearly
degenerate modes, assisted by the laser nonlinearity. Surprisingly,
these patterns show high resemblance to patterns generated in other
nonlinear scenarios that are completely different both in scale and in
mechanism.
Department of Electrical Engineering, Technion, Haifa 32000, Israel.
