18 research outputs found
Photo-oxidative tuning of individual and coupled GaAs photonic crystal cavities
We demonstrate a new photo-induced oxidation technique for tuning GaAs
photonic crystal cavities using a pulsed laser with an
average power of . The laser oxidizes a small diameter spot, reducing the local index of refraction
and blueshifting the cavity. The tuning progress can be actively monitored in
real time. We also demonstrate tuning an individual cavity within a pair of
proximity-coupled cavities, showing that this method can be used to correct
undesired frequency shifts caused by fabrication imperfections in cavity
arrays.Comment: 4 pages, 3 figure
Optical fiber tips functionalized with semiconductor photonic crystal cavities
We demonstrate a simple and rapid epoxy-based method for transferring
photonic crystal cavities to the facets of optical fibers. Passive Si cavities
were measured via fiber taper coupling as well as direct transmission from the
fiber facet. Active quantum dot containing GaAs cavities showed
photoluminescence that was collected both in free space and back through the
original fiber. Cavities maintain a high quality factor (2000-4000) in both
material systems. This new design architecture provides a practical
mechanically stable platform for the integration of photonic crystal cavities
with macroscale optics and opens the door for novel research on fiber-coupled
cavity devices.Comment: 10 pages, 5 figure
Nanobeam photonic crystal cavity quantum dot laser
The lasing behavior of one dimensional GaAs nanobeam cavities with embedded
InAs quantum dots is studied at room temperature. Lasing is observed throughout
the quantum dot PL spectrum, and the wavelength dependence of the threshold is
calculated. We study the cavity lasers under both 780 nm and 980 nm pump,
finding thresholds as low as 0.3 uW and 19 uW for the two pump wavelengths,
respectively. Finally, the nanobeam cavity laser wavelengths are tuned by up to
7 nm by employing a fiber taper in near proximity to the cavities. The fiber
taper is used both to efficiently pump the cavity and collect the cavity
emission.Comment: 8 pages; 6 figure
A photonic crystal cavity-optical fiber tip nanoparticle sensor for biomedical applications
We present a sensor capable of detecting solution-based nanoparticles using
an optical fiber tip functionalized with a photonic crystal cavity. When sensor
tips are retracted from a nanoparticle solution after being submerged, we find
that a combination of convective fluid forces and optically-induced trapping
cause an aggregation of nanoparticles to form directly on cavity surfaces. A
simple readout of quantum dot photoluminescence coupled to the optical fiber
shows that nanoparticle presence and concentration can be detected through
modified cavity properties. Our sensor can detect both gold and iron oxide
nanoparticles and can be utilized for molecular sensing applications in
biomedicine.Comment: 13 pages, 5 figure
Coupled fiber taper extraction of 1.53 um photoluminescence from erbium doped silicon nitride photonic crystal cavities
Optical fiber tapers are used to collect photoluminescence emission at ~1.5
um from photonic crystal cavities fabricated in erbium doped silicon nitride on
silicon. Photoluminescence collection via fiber taper is enhanced 2.5 times
relative to free space, with a total taper collection efficiency of 53%. By
varying the fiber taper offset from the cavity, a broad tuning range of
coupling strength is obtained. This material system combined with fiber taper
collection is promising for building on-chip optical amplifiers.Comment: 10 pages, 7 figure
Fiber taper collection of photoluminescence at 1.54 μm from erbium doped silicon nitride photonic crystal cavities
Photoluminescence at 1.54 μm from Er-doped silicon nitride embedded in silicon photonic crystal cavities was extracted with 2.5× greater collection efficiency compared to free space emission, with loaded Q values of up to 98% of the intrinsic Q