21 research outputs found
Quantum Memory for Photons in Case of Many Close Lying Exciton Resonances in Solids
The possibility of storage of quantum information with photons is studied in
the case of resonant transitions via many close lying exciton levels in a solid
with impurity Lambda-atoms. The upper levels of the impurity atom form resonant
Fano states, similar to the autoionization atomic states, due to the
configuration interaction with the continuum of the exciton band. In this case
slowing of light pulses is shown to be realistic, in the presence of the
control field, down to the group velocity much lower than that in vacuum. The
possibility of storage and reconstruction of a quantum pulse is studied in the
case of the instantaneous switching on/off of the control field. It is shown
that the signal quantum pulse cannot be stored undistorted for differing values
of Fano parameters and for non-zero two-photon detuning and decay rate between
the lower levels (decoherence). However, for small difference of the Fano
parameters and for small values of the two-photon detuning and the decoherence
there is no distortion in the case where the length of the pulse is much longer
than the linear absorption (amplification) length, so the shape and quantum
state of the light pulse can be restored.Comment: 15 pages, 3 figure