11,955 research outputs found
Photonic band-gap engineering for volume plasmon polaritons in multiscale multilayer hyperbolic metamaterials
We theoretically study the propagation of large-wavevector waves (volume
plasmon polaritons) in multilayer hyperbolic metamaterials with two levels of
structuring. We show that when the parameters of a subwavelength
metal-dielectric multilayer ("substructure") are modulated ("superstructured")
on a larger, wavelength scale, the propagation of volume plasmon polaritons in
the resulting multiscale hyperbolic metamaterials is subject to photonic band
gap phenomena. A great degree of control over such plasmons can be exerted by
varying the superstructure geometry. When this geometry is periodic, stop bands
due to Bragg reflection form within the volume plasmonic band. When a cavity
layer is introduced in an otherwise periodic superstructure, resonance peaks of
the Fabry-Perot nature are present within the stop bands. More complicated
superstructure geometries are also considered. For example, fractal Cantor-like
multiscale metamaterials are found to exhibit characteristic self-similar
spectral signatures in the volume plasmonic band. Multiscale hyperbolic
metamaterials are shown to be a promising platform for large-wavevector bulk
plasmonic waves, whether they are considered for use as a new kind of
information carrier or for far-field subwavelength imaging.Comment: 12 pages, 10 figures, now includes Appendix
Chalcogenide Glass-on-Graphene Photonics
Two-dimensional (2-D) materials are of tremendous interest to integrated
photonics given their singular optical characteristics spanning light emission,
modulation, saturable absorption, and nonlinear optics. To harness their
optical properties, these atomically thin materials are usually attached onto
prefabricated devices via a transfer process. In this paper, we present a new
route for 2-D material integration with planar photonics. Central to this
approach is the use of chalcogenide glass, a multifunctional material which can
be directly deposited and patterned on a wide variety of 2-D materials and can
simultaneously function as the light guiding medium, a gate dielectric, and a
passivation layer for 2-D materials. Besides claiming improved fabrication
yield and throughput compared to the traditional transfer process, our
technique also enables unconventional multilayer device geometries optimally
designed for enhancing light-matter interactions in the 2-D layers.
Capitalizing on this facile integration method, we demonstrate a series of
high-performance glass-on-graphene devices including ultra-broadband on-chip
polarizers, energy-efficient thermo-optic switches, as well as graphene-based
mid-infrared (mid-IR) waveguide-integrated photodetectors and modulators
Solid-state lasers for coherent communication and remote sensing
Semiconductor-diode laser-pumped solid-state lasers have properties that are superior to other lasers for the applications of coherent communication and remote sensing. These properties include efficiency, reliability, stability, and capability to be scaled to higher powers. We have demonstrated that an optical phase-locked loop can be used to lock the frequency of two diode-pumped 1.06 micron Nd:YAG lasers to levels required for coherent communication. Monolithic nonplanar ring oscillators constructed from solid pieces of the laser material provide better than 10 kHz frequency stability over 0.1 sec intervals. We have used active feedback stabilization of the cavity length of these lasers to demonstrate 0.3 Hz frequency stabilization relative to a reference cavity. We have performed experiments and analysis to show that optical parametric oscillators (OPO's) reproduce the frequency stability of the pump laser in outputs that can be tuned to arbitrary wavelengths. Another measurement performed in this program has demonstrated the sub-shot-noise character of correlations of the fluctuations in the twin output of OPO's. Measurements of nonlinear optical coefficients by phase-matched second harmonic generation are helping to resolve inconsistency in these important parameters
A hemispherical, high-solid-angle optical micro-cavity for cavity-QED studies
We report a novel hemispherical micro-cavity that is comprised of a planar
integrated semiconductor distributed Bragg reflector (DBR) mirror, and an
external, concave micro-mirror having a radius of curvature .
The integrated DBR mirror containing quantum dots (QD), is designed to locate
the QDs at an antinode of the field in order to maximize the interaction
between the QD and the cavity. The concave micro-mirror, with high-reflectivity
over a large solid-angle, creates a diffraction-limited (sub-micron) mode-waist
at the planar mirror, leading to a large coupling constant between cavity mode
and QD. The half-monolithic design gives more spatial and spectral tuning
abilities, relatively to fully monolithic structures. This unique micro-cavity
design will potentially enable us to both reach the cavity quantum
electrodynamics (QED) strong coupling regime and realize the deterministic
generation of single photons on demand.Comment: 15 pages, 17 figures, final versio
High Finesse Fiber Fabry-Perot Cavities: Stabilization and Mode Matching Analysis
Fiber Fabry-Perot cavities, formed by micro-machined mirrors on the
end-facets of optical fibers, are used in an increasing number of technical and
scientific applications, where they typically require precise stabilization of
their optical resonances. Here, we study two different approaches to construct
fiber Fabry-Perot resonators and stabilize their length for experiments in
cavity quantum electrodynamics with neutral atoms. A piezo-mechanically
actuated cavity with feedback based on the Pound-Drever-Hall locking technique
is compared to a novel rigid cavity design that makes use of the high passive
stability of a monolithic cavity spacer and employs thermal self-locking and
external temperature tuning. Furthermore, we present a general analysis of the
mode matching problem in fiber Fabry-Perot cavities, which explains the
asymmetry in their reflective line shapes and has important implications for
the optimal alignment of the fiber resonators. Finally, we discuss the issue of
fiber-generated background photons. We expect that our results contribute
towards the integration of high-finesse fiber Fabry-Perot cavities into compact
and robust quantum-enabled devices in the future.Comment: The Supplemental Material is included in the source code of the
article that can be downloaded from this arXiv page (see "Other formats").
Peer-reviewed version with changes to text and figure
Reflectance measurement of two-dimensional photonic crystal nanocavities with embedded quantum dots
The spectra of two-dimensional photonic crystal slab nanocavities with
embedded InAs quantum dots are measured by photoluminescence and reflectance.
In comparing the spectra taken by these two different methods, consistency with
the nanocavities' resonant wavelengths is found. Furthermore, it is shown that
the reflectance method can measure both active and passive cavities. Q-factors
of nanocavities, whose resonant wavelengths range from 1280 to 1620 nm, are
measured by the reflectance method in cross polarization. Experimentally,
Q-factors decrease for longer wavelengths and the intensity, reflected by the
nanocavities on resonance, becomes minimal around 1370 nm. The trend of the
Q-factors is explained by the change of the slab thickness relative to the
resonant wavelength, showing a good agreement between theory and experiment.
The trend of reflected intensity by the nanocavities on resonance can be
understood as effects that originate from the PC slab and the underlying air
cladding thickness. In addition to three dimensional finite-difference
time-domain calculations, an analytical model is introduced that is able to
reproduce the wavelength dependence of the reflected intensity observed in the
experiment.Comment: 24 pages, 7 figures, corrected+full versio
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