Topic
Atomic coherence
About: Atomic coherence is a research topic. Over the lifetime, 877 publications have been published within this topic receiving 29395 citations.
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TL;DR: In this paper, the response of a coherently prepared four-level λ-type system, interacting with two electromagnetic fields in a Doppler-free pump-probe configuration is analytically formulated.
Abstract: The response of a coherently prepared four-level λ-type system, interacting with two electromagnetic fields in a Doppler-free pump–probe configuration is analytically formulated. Under density matrix formalism the probe coherence (field-dependent phase) and atomic coherence (field-independent phase) are introduced through the off-diagonal matrix elements. The coherent effects on probe response is investigated for probe coherence, as well as for the driving contribution (coherence) of the pump field. We show how probe coherence can modify the Rabi splitting and two-photon absorption, through shifting and broadening of spectral lines for on- and off-resonance pumping, respectively. In addition, we report on the enhancement of absorptionless dispersion (i.e. refractive index for on and around probe resonance) and two-photon absorption, via coherent control of the driving contribution of the pump field.
TL;DR: In this paper, a laser model which may operate in the absence of population inversion is proposed and it is found that the realization of lasing without inversion in this model is due to the change of noninversion condition along with the creation of atomic coherence, instead of a coherence-term-induced gain enhancement.
Abstract: A laser model which may operate in the absence of population inversion is proposed. It is found that the realization of lasing without inversion in this model is due to the change of noninversion condition along with the creation of atomic coherence, instead of a coherence-term-induced gain enhancement.
03 Jun 2019
TL;DR: In this article, the entanglement of a quantum system consisting of a Jaynes-Cummings atom, thermal lossless cavity and an isolated atom was investigated, and the analytical expressions of the atom-atom negativity for separable, separable coherent and entangled initial atomic states were obtained.
Abstract: We investigated the entanglement of a quantum system consisting of a Jaynes-Cummings atom, thermal lossless cavity and an isolated atom. The analytical expressions of the atom-atom negativity for separable, separable coherent and entangled initial atomic states were obtained. The influence of initial atomic coherence, detuning between the atomic transition frequency and the field frequency and direct dipole-dipole interaction on an atom- atom entanglement is examined. We showed that for a separable and separable coherent initial atomic states a detuning might cause high atom-atom entanglement in the presence of the dipole-dipole interaction even for thermal field with high intensity. We also obtained that for entangled initial atomic states a detuning causes a stabilization of an entanglement oscillations.
TL;DR: In this paper, the authors proposed a scheme for generating fully three-mode continuous variable entanglement between three non-degenerate (nondegenerate) modes in a single-atom laser.
Abstract: We proposed a scheme for generating fully three-mode
continuous-variable (CV) entanglement between three nondegenerate
cavity modes in a single-atom laser. In our scheme, the single-atom
laser consists of a four-level atom inside a triply resonant cavity,
and the atomic coherence is induced by two classical laser fields
driving the corresponding atomic transitions. To demonstrate the
generation of entanglement, we numerically simulated the dynamics of
this system, and the numerical simulation shows that the single-atom
laser considered here can be seen as a three-mode CV entanglement
amplifier even in the presence of cavity losses. Moreover, we also
show that the generation of entanglement doesn’t depend intensively
on the initial condition of cavity field, and the fully three-mode
CV entanglement can be realized no matter the three entangled
(nondegenerate) modes are initially in the same state or different
states based on our scheme.
TL;DR: In this paper, the authors show that the high frequency fluctuations of both the intensities and the intensity difference can be squeezed below the shot noise limit due to the nonadiabatic effects.
Abstract: In an electromagnetically induced transparency system, the atoms have long-lived coherence compared to the cavity lifetime and interact nonadiabatically with the laser fields. We show that the high frequency fluctuations of both the intensities and the intensity difference can be squeezed below the shot noise limit due to the nonadiabatic effects. This noise squeezing can be used to enhance the precision in the short time measurements based on the intensities or the intensity difference.