5,226 research outputs found
Quantum Monte Carlo study of ring-shaped polariton parametric luminescence in a semiconductor microcavity
We present a quantum Monte Carlo study of the quantum correlations in the
parametric luminescence from semiconductor microcavities in the strong
exciton-photon coupling regime. As already demonstrated in recent experiments,
a ring-shaped emission is obtained by applying two identical pump beams with
opposite in-plane wavevectors, providing symmetrical signal and idler beams
with opposite in-plane wavevectors on the ring. We study the squeezing of the
signal-idler difference noise across the parametric instability threshold,
accounting for the radiative and non-radiative losses, multiple scattering and
static disorder. We compare the results of the complete multimode Monte Carlo
simulations with a simplified linearized quantum Langevin analytical model
Quantum Noise in Multipixel Image Processing
We consider the general problem of the quantum noise in a multipixel
measurement of an optical image. We first give a precise criterium in order to
characterize intrinsic single mode and multimode light. Then, using a
transverse mode decomposition, for each type of possible linear combination of
the pixels' outputs we give the exact expression of the detection mode, i.e.
the mode carrying the noise. We give also the only way to reduce the noise in
one or several simultaneous measurements.Comment: 8 pages and 1 figur
Non-linear and quantum optics of a type II OPO containing a birefringent element Part 1: Classical operation
We describe theoretically the main characteristics of the steady state regime
of a type II Optical Parametric Oscillator (OPO) containing a birefringent
plate. In such a device the signal and idler waves are at the same time
linearly coupled by the plate and nonlinearly coupled by the
crystal. This mixed coupling allows, in some well-defined range of the control
parameters, a frequency degenerate operation as well as phase locking between
the signal and idler modes. We describe here a complete model taking into
account all possible effects in the system, \emph{i.e.} arbitrary rotation of
the waveplate, non perfect phase matching, ring and linear cavities. This model
is able to explain the detailed features of the experiments performed with this
system.Comment: To be published in EPJ
General Cram\'er-Rao bound for parameter estimation using Gaussian multimode quantum resources
Multimode Gaussian quantum light, including multimode squeezed and/or
multipartite quadrature entangled light, is a very general and powerful quantum
resource with promising applications to quantum information processing and
metrology involving continuous variables. In this paper, we determine the
ultimate sensitivity in the estimation of any parameter when the information
about this parameter is encoded in such Gaussian light, irrespective of the
exact information extraction protocol used in the estimation. We then show
that, for a given set of available quantum resources, the most economical way
to maximize the sensitivity is to put the most squeezed state available in a
well-defined light mode. This implies that it is not possible to take advantage
of the existence of squeezed fluctuations in other modes, nor of quantum
correlations and entanglement between different modes. We show that an
appropriate homodyne detection scheme allows us to reach this Cramr-Rao bound.
We apply finally these considerations to the problem of optimal phase
estimation using interferometric techniques
Quantum squeezing generation versus photon localization in a disordered microcavity
We investigate theoretically the nonlinear dynamics induced by an intense
pump field in a disordered planar microcavity. Through a self-consistent
theory, we show how the generation of quantum optical noise squeezing is
affected by the breaking of the in-plane translational invariance and the
occurrence of photon localization. We find that the generation of single-mode
Kerr squeezing for the ideal planar case can be prevented by disorder as a
result of multimode nonlinear coupling, even when the other modes are in the
vacuum state. However, the excess noise is a non-monotonous function of the
disorder amplitude. In the strong localization limit, we show that the system
becomes protected with respect to this fundamental coupling mechanism and that
the ideal quadrature squeezing generation can be obtained
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