13 research outputs found
Non-linear photonic crystals as a source of entangled photons
Non-linear photonic crystals can be used to provide phase-matching for
frequency conversion in optically isotropic materials. The phase-matching
mechanism proposed here is a combination of form birefringence and phase
velocity dispersion in a periodic structure. Since the phase-matching relies on
the geometry of the photonic crystal, it becomes possible to use highly
non-linear materials. This is illustrated considering a one-dimensional
periodic AlGaAs / air structure for the generation of 1.5
m light. We show that phase-matching conditions used in schemes to create
entangled photon pairs can be achieved in photonic crystals.Comment: 4 pages, 3 figure
Photon statistics from coupled quantum dots
We present an optical study of closely-spaced self-assembled InAs/GaAs
quantum dots. The energy spectrum and correlations between photons subsequently
emitted from a single pair provide not only clear evidence of coupling between
the quantum dots but also insight into the coupling mechanism. Our results are
in agreement with recent theories predicting that tunneling is largely
suppressed between nonidentical quantum dots and that the interaction is
instead dominated by dipole-dipole coupling and phonon-assisted energy transfer
processes.Comment: 4 pages, 4 figures, to appear in Phys. Re
Measurement of the Phase and Intensity Profile of Surface Plasmon Laser Emission
We study the near-
and far-field radiation patterns of surface
plasmon (SP) lasers in metal hole arrays and observe radially polarized
vortex-vector laser beams in both near and far field. Besides the
intensity profile, also the complementary phase profile is obtained
with a beam block experiment, where we block part of the beam in the
near field, measure the resulting changes in the far field, and retrieve
the phase using an iterative algorithm. This phase profile provides
valuable information on the feedback mechanisms and coherence of the
laser and shows that our SP laser operates in a phase-slip mode instead
of a pure dark mode. To explain our observations, we extend the standard
model for distributed feedback lasers by introducing a position dependence
in the optical gain and refractive index