7 research outputs found
Non-Hermitian wave packet approximation for coupled two-level systems in weak and intense fields
We introduce an accurate non-Hermitian Schr\"odinger-type approximation of
Bloch optical equations for two-level systems. This approximation provides a
complete description of the excitation, relaxation and decoherence dynamics in
both weak and strong laser fields. In this approach, it is sufficient to
propagate the wave function of the quantum system instead of the density
matrix, providing that relaxation and dephasing are taken into account via
automatically-adjusted time-dependent gain and decay rates. The developed
formalism is applied to the problem of scattering and absorption of
electromagnetic radiation by a thin layer comprised of interacting two-level
emitters
Theory of Dipole Induced Electromagnetic Transparency
A detailed theory describing linear optics of vapors comprised of interacting
multi-level quantum emitters is proposed. It is shown both by direct
integration of Maxwell-Bloch equations and using a simple analytical model that
at large densities narrow transparency windows appear in otherwise completely
opaque spectra. The existence of such windows is attributed to overlapping
resonances. This effect, first introduced for three-level systems in [R.
Puthumpally-Joseph, M. Sukharev, O. Atabek and E. Charron, Phys. Rev. Lett.
113, 163603 (2014)], is due to strongly enhanced dipole-dipole interactions at
high emitters' densities. The presented theory extends this effect to the case
of multilevel systems. The theory is applied to the D1 transitions of
interacting Rb-85 atoms. It is shown that at high atomic densities, Rb-85 atoms
can behave as three-level emitters exhibiting all the properties of dipole
induced electromagnetic transparency. Applications including slow light and
laser pulse shaping are also proposed
Dipole-Induced Electromagnetic Transparency
We determine the optical response of a thin and dense layer of interacting
quantum emitters. We show that in such a dense system, the Lorentz redshift and
the associated interaction broadening can be used to control the transmission
and reflection spectra. In the presence of overlapping resonances, a
Dipole-Induced Electromagnetic Transparency (DIET) regime, similar to
Electromagnetically Induced Transparency (EIT), may be achieved. DIET relies on
destructive interference between the electromagnetic waves emitted by quantum
emitters. Carefully tuning material parameters allows to achieve narrow
transmission windows in otherwise completely opaque media. We analyze in
details this coherent and collective effect using a generalized Lorentz model
and show how it can be controlled. Several potential applications of the
phenomenon, such as slow light, are proposed
Non-Markovianity in the optimal control of an open quantum system described by hierarchical equations of motion
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