395 research outputs found
Polariton Local States in Periodic Bragg Multiple Quantum Well Structures
We analytically study optical properties of several types of defects in Bragg
multiple quantum well structures. We show that a single defect leads to two
local polariton modes in the photonic band gap. These modes lead to
peculiarities in reflection and transmission spectra. Detailed recommendations
for experimental observation of the studied effects are given.Comment: 3 pages, 1 figure, RevTex, Submitted to Opt. Let
Determination of the Photographic Position of an Object with the Aid of Two and Three Reference Stars
Determination of photographic position of object with aid of two and three reference star
Impurity-induced polaritons in a one-dimensional chain
A detailed analytical study of an impurity induced polariton band arising
inside a spectral gap between lower and upper polariton branches is presented.
Using the microcanonical method, we calculate the density of states and
localization length of the impurity polaritons. Analytical results are compared
with numerical simulations and excellent agreement is found.Comment: 10 pages, 3 figures, RevTe
Effect of local pumping on random laser modes
We have developed a numerical method based on the transfer matrix to
calculate the quasimodes and lasing modes in one-dimensional random systems.
Depending on the relative magnitude of the localization length versus the
system size, there are two regimes in which the quasimodes are distinct in
spatial profile and frequency distribution. In the presence of uniform gain,
the lasing modes have one-to-one correspondence to the quasimodes in both
regimes. Local excitation may enhance the weight of a mode within the gain
region due to local amplification, especially in a weakly scattering system.Comment: 8 pages, 5 figure
Resonance tunneling of polaritons in 1-D chain with a single defect
We consider propagation of coupled waves (polaritons) formed by a scalar
electromagnetic wave and excitations of a finite one dimensional chain of
dipoles. It is shown that a microscopic defect (an impurity dipole) embedded in
the chain causes resonance tunneling of the electromagnetic wave with the
frequency within the forbidden band between two polariton branches. We
demonstrate that resonance tunneling occurs due to local polariton states
caused by the defect.Comment: 11 pages, 9 figures (PS-format), RevTe
Local polariton modes and resonant tunneling of electromagnetic waves through periodic Bragg multiple quantum well structures
We study analytically defect polariton states in Bragg multiple-quantum-well
structures and defect induced changes in transmission and reflection spectra.
Defect layers can differ from the host layers in three ways: exciton-light
coupling strength, exciton resonance frequency, and inter-well spacing. We show
that a single defect leads to two local polariton modes in the photonic
bandgap. These modes cause peculiarities in reflection and transmission
spectra. Each type of defect can be reproduced experimentally, and we show that
each of these plays a distinct role in the optical properties of the system.
For some defects, we predict a narrow transmission window in the forbidden gap
at the frequency set by parameters of the defect. We obtain analytical
expressions for corresponding local frequencies as well as for reflection and
transmission coefficients. We show that the presence of the defects leads to
resonant tunneling of the electromagnetic waves via local polariton modes
accompanied by resonant enhancement of the field inside the sample, even when a
realistic absorption is taken into account. On the basis of the results
obtained, we make recommendations regarding the experimental observation of the
effects studied in readily available samples.Comment: 17 pages, 10 figures, RevTex, Submitted to PR
Scaling Properties of 1D Anderson Model with Correlated Diagonal Disorder
Statistical and scaling properties of the Lyapunov exponent for a
tight-binding model with the diagonal disorder described by a dichotomic
process are considered near the band edge. The effect of correlations on
scaling properties is discussed. It is shown that correlations lead to an
additional parameter governing the validity of single parameter scaling.Comment: 5 pages, 3 figures, RevTe
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