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FIZIKA A 19 (2010) 4 , 215-240
 
COHERENT CONTROL OF SPONTANEOUS EMISSION SPECTRUM IN A DOUBLY DRIVEN Y-TYPE ATOM
BIBHAS KUMAR DUTTAa and PRASANTA KUMAR MAHAPATRAb
aDepartment of Physics, J. K. College, Purulia 723 101, India
bDepartment of Physics and Technophysics, Vidyasagar University, Midnapore 721 102, India
Received 1 February 2009; Revised manuscript received 8 November 2010
Accepted 9 February 2011 Online 7 April 2011
We have studied the dynamic control of the spontaneous emission
spectrum in a Y-type atomic system driven by two coherent fields.
In different dynamic conditions, the evolution of coherent spectral
features in the bare-state model, has been analyzed by using the
dressed-state model. For the system under purely dissipative environment,
it has been shown that the
behaviour of spectral components can be coherently controlled
by changing the values of the Rabi frequencies and detunings of
external fields. At the condition of resonant evolution of spectra,
present work highlights that the emission line shape can be
strongly modified for unequal decay rates of the uppermost
doublet states. In this situation, the phenomenon of
constructive quantum interference gives rise to the emergence
of a single peak at a certain spectral position when two
distinct peaks disappear at the other spectral positions.
Owing to the mutual orientation of polarizations
of the fields interacting with the atom in a specific configuration,
we have incorporated the static phase-variation effect to exhibit
phase-dependent spectra. We consider
the present model with a typical field configuration such that the
frequency mismatch between two coherent fields introduces the
dynamic phase-variation effect. This phenomenon leads to obtain anomalous
peak-shifting effect accompanied by the selective quenching
of emission within the spectral profile.
PACS numbers: 42.50.Ct, 32.80.Qk, 32.50.+d
UDC 539.184, 539.186
Keywords: doubly driven Y-type atom, dynamic control of coherent spectral features,
incoherent elimination of spectral component, dependence of the line
intensity on the incoherent pumping rate, static and dynamic phase-variation
effects, phase-dependent emission spectra, anomalous peak shifting effect
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