66 research outputs found
Dynamical tunneling in optical cavities
The lifetime of whispering gallery modes in a dielectric cavity with a
metallic inclusion is shown to fluctuate by orders of magnitude when size and
location of the inclusion are varied. We ascribe these fluctuations to
tunneling transitions between resonances quantized in different regions of
phase space. This interpretation is confirmed by a comparison of the classical
phase space structure with the Husimi distribution of the resonant modes. A
model Hamiltonian is introduced that describes the phenomenon and shows that it
can be expected in a more general class of systems.Comment: 8 pages LaTeX with 5 postscript figure
Observation of Scarred Modes in Asymmetrically Deformed Microcylinder Lasers
We report observation of lasing in the scarred modes in an asymmetrically
deformed microcavity made of liquid jet. The observed scarred modes correspond
to morphology-dependent resonance of radial mode order 3 with their Q values in
the range of 10^6. Emission directionality is also observed, corresponding to a
hexagonal unstable periodic orbit.Comment: 4 pages, 6 figure
Light emission patterns from stadium-shaped semiconductor microcavity lasers
We study light emission patterns from stadium-shaped semiconductor (GaAs)
microcavity lasers theoretically and experimentally. Performing systematic wave
calculations for passive cavity modes, we demonstrate that the averaging by
low-loss modes, such as those realized in multi-mode lasing, generates an
emission pattern in good agreement with the ray model's prediction. In
addition, we show that the dependence of experimental far-field emission
patterns on the aspect ratio of the stadium cavity is well reproduced by the
ray model.Comment: 5 pages, 4 figure
Semiclassical theory of the emission properties of wave-chaotic resonant cavities
We develop a perturbation theory for the lifetime and emission intensity for
isolated resonances in asymmetric resonant cavities. The inverse lifetime
and the emission intensity in the open system are
expressed in terms of matrix elements of operators evaluated with eigenmodes of
the closed resonator. These matrix elements are calculated in a semiclassical
approximation which allows us to represent and as sums
over the contributions of rays which escape the resonator by refraction.Comment: 4 pages, 2 color figure
Boundary element method for resonances in dielectric microcavities
A boundary element method based on a Green's function technique is introduced
to compute resonances with intermediate lifetimes in quasi-two-dimensional
dielectric cavities. It can be applied to single or several optical resonators
of arbitrary shape, including corners, for both TM and TE polarization. For
cavities with symmetries a symmetry reduction is described. The existence of
spurious solutions is discussed. The efficiency of the method is demonstrated
by calculating resonances in two coupled hexagonal cavities.Comment: 9 pages, 7 figures (quality reduced
Regular Spectra and Universal Directionality of Emitted Radiation from a Quadrupolar Deformed Microcavity
We have investigated quasi-eigenmodes of a quadrupolar deformed microcavity
by extensive numerical calculations. The spectral structure is found to be
quite regular, which can be explained on the basis of the fact that the
microcavity is an open system. The far-field emission directions of the modes
show unexpected similarity irrespective of their distinct shapes in phase
space. This universal directionality is ascribed to the influence from the
geometry of the unstable manifolds in the corresponding ray dynamics.Comment: 10 pages 11 figure
Directional interacting whispering gallery modes in coupled dielectric microdisks
We study the optical interaction in a coupled dielectric microdisks by
investigating the splitting of resonance positions of interacting whispering
gallery modes (WGMs) and their pattern change, depending on the distance
between the microdisks. It is shown that the interaction between the WGMs with
odd parity about y-axis becomes appreciable at a distance less than a
wavelength and causes directional emissions of the resulting interacting WGMs.
The directionality of the interacting WGMs can be understood in terms of an
effective boundary deformation in ray dynamical analysis. We also discuss about
the oscillation of the splitting when the distance is greater than a
wavelength.Comment: 7 pages, 10 figure
Chaotic Waveguide-Based Resonators for Microlasers
We propose the construction of highly directional emission microlasers using
two-dimensional high-index semiconductor waveguides as {\it open} resonators.
The prototype waveguide is formed by two collinear leads connected to a cavity
of certain shape. The proposed lasing mechanism requires that the shape of the
cavity yield mixed chaotic ray dynamics so as to have the appropiate (phase
space) resonance islands. These islands allow, via Heisenberg's uncertainty
principle, the appearance of quasi bound states (QBS) which, in turn,
propitiate the lasing mechanism. The energy values of the QBS are found through
the solution of the Helmholtz equation. We use classical ray dynamics to
predict the direction and intensity of the lasing produced by such open
resonators for typical values of the index of refraction.Comment: 5 pages, 5 figure
Experimental Test of a Two-dimensional Approximation for Dielectric Microcavities
Open dielectric resonators of different shapes are widely used for the
manufacture of microlasers. A precise determination of their resonance
frequencies and widths is crucial for their design. Most microlasers have a
flat cylindrical geometry, and a two-dimensional approximation, the so-called
method of the effective index of refraction, is commonly employed for numerical
calculations. Our aim has been an experimental test of the precision and
applicability of a model based on this approximation. We performed very
thorough and accurate measurements of the resonance frequencies and widths of
two passive circular dielectric microwave resonators and found significant
deviations from the model predictions. From this we conclude that the model
generally fails in the quantitative description of three-dimensional dielectric
resonators.Comment: 10 pages, 13 figure
Chaos-assisted emission from asymmetric resonant cavity microlasers
We study emission from quasi-one-dimensional modes of an asymmetric resonant
cavity that are associated with a stable periodic ray orbit confined inside the
cavity by total internal reflection. It is numerically demonstrated that such
modes exhibit directional emission, which is explained by chaos-assisted
emission induced by dynamical tunneling. Fabricating semiconductor microlasers
with the asymmetric resonant cavity, we experimentally demonstrate the
selective excitation of the quasi-one-dimensional modes by employing the device
structure to preferentially inject currents to these modes and observe
directional emission in good accordance with the theoretical prediction based
on chaos-assisted emission.Comment: 9 pages, 10 figures, some figures are in reduced qualit
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