286 research outputs found
Directional waveguide coupling from a wavelength-scale deformed microdisk laser
We demonstrate uni-directional evanescent coupling of lasing emission from a
wavelength-scale deformed microdisk to a waveguide. This is attributed to the
Goos-H\"anchen shift and Fresnel filtering effect that result in a spatial
separation of the clockwise (CW) and counter-clockwise (CCW) propagating ray
orbits. By placing the waveguide tangentially at different locations to the
cavity boundary, we may selectively couple the CW (CCW) wave out, leaving the
CCW (CW) wave inside the cavity, which also reduces the spatial hole burning
effect. The device geometry is optimized with a full-wave simulation tool, and
the lasing behavior and directional coupling are confirmed experimentally.Comment: 5 pages, 4 figure
Emission spectrum of a dressed exciton-biexciton complex in a semiconductor quantum dot
The photoluminescence spectrum of a single quantum dot was recorded as a
secondary resonant laser optically dressed either the vacuum-to-exciton or the
exciton-to-biexciton transitions. High-resolution polarization-resolved
measurements using a scanning Fabry-Perot interferometer reveal splittings of
the linearly-polarized fine-structure states that are non-degenerate in an
asymmetric quantum dot. These splittings manifest as either triplets or
doublets and depend sensitively on laser intensity and detuning. Our approach
realizes complete resonant control of a multi-excitonic system in emission,
which can be either pulsed or continuous-wave, and offers direct access to the
emitted photons.Comment: 4 pages, 4 figure
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