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Phase-sensitive amplification in a three-level atomic system

Nadeem A. Ansari, Muhammad Suhail Zubairy, Julio R. Gea-Banacloche

Published May 21, 1990• 12 citations
OpenAlex

Abstract

We have studied the amplification of a single-mode electromagnetic field by an atomic system with a three-level cascade structure in two-photon resonance conditions when the top and bottom levels are mixed coherently by a strong external resonant field. We find different kinds of phase-sensitive amplification for different values of the driving field strength. For a very high driving field and near one-photon resonance, the system approaches an ideal parametric amplifier.

Related papers

Phase-sensitive amplification in a three-level atomic system

Nadeem A. Ansari, Julio R. Gea-Banacloche, Muhammad Suhail Zubairy

A linear theory of two-photon amplification by three-level atoms in the cascade configuration is developed, where a coherence is induced between the top and bottom levels, by an external classical driving field. It is shown that this system becomes an ideal parametric amplifier for sufficiently strong driving field, whereas for a weak driving field it is a phase-insensitive amplifier. In between these two extremes, one finds phase-sensitive amplification as well as squeezing for a certain range. The system does not, however, reduce to a model studied previously where the atomic coherence was treated as an initial condition. The system is also studied in a cavity configuration: It is predicted that the oscillator may behave as a two-photon correlated emission laser, i.e., its phase diffusion coefficient vanishes.

Physical Review A•May 1, 1990•125 citations

Theory of a two-mode phase-sensitive amplifier

Nadeem A. Ansari

A theory of two-mode phase-sensitive amplification by a three-level atomic system in the cascade configuration is presented, within the framework of the theory of multiwave mixing. Two photons of a strong external pump field induce coherence between the top and bottom levels. It is shown that both quadratures of the field modes acquire unequal gain and added noise. For large values of the dimensionless pump intensity, with a particular choice of its phase, and zero side-mode detuning, the system behaves as a nondegenerate parametric amplifier.

Physical Review A•Aug 1, 1992•38 citations

Quantum state measurement using phase-sensitive amplification in a driven three-level atomic system

Mashhood Ahmad, Shahid Qamar, Muhammad Suhail Zubairy

Phase-sensitive amplification in a three-level atomic system exhibits interesting features. For example, in the zero-detuning limit and for sufficiently strong driving field, this system becomes an ideal parametric amplifier, whereas, for a weak driving field it is a phase-insensitive amplifier [Ansari et al., Phys. Rev. A 41, 5179 (1990)]. In this paper, we show that this system could be used to measure the quantum state of the radiation field inside a cavity. To reconstruct the quantum state, we amplify it through a three-level atomic system and in the parametric limit, when noise in both the quadratures approaches to zero measure the amplified field quadrature. The complete quadrature distribution is obtained by measuring the quadratures for different values of the driving field phases. The inverse Radon transformation is then employed to reconstruct the original quantum state. Our scheme is insensitive to the problems associated with nonunit detector efficiency in homodyne detection measurement.

Physical Review A•Jul 1, 2001•9 citations

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Z Chen, Helen S. Freedhoff

The top level of a three-level atom is populated by resonant two-photon optical pumping from the bottom level by a field intense enough to produce dynamic Stark splitting. The frequencies and intensities are calculated for the one-photon cascade emission to the ground state via a nearly resonant intermediate level. Two strong (shifted) doublets near the atomic frequencies, and a weaker triplet centred at the laser frequency are predicted.

Journal of Physics B Atomic Molecular and Optical Physics•Feb 14, 1990•0 citations

Violation of Bell's inequality in a driven three-level cascade atomic system

Nadeem A. Ansari

A fully quantum-mechanical theory of multiwave mixing in a three-level cascade atomic system with two field modes is presented. The top and bottom levels are coupled with a strong external field. Certain conditions on the Rabi frequency and detuning of the driving field have been worked out for the violation of Bell's inequality and for when the system may behave as nondegenerate parametric oscillator.

Physical Review A•Mar 1, 1997•6 citations

Phase control of light amplification without inversion in two Lambda-type atomic systems

Hai-Hua Wang, Jin‐Hui Wu, Jin-Yue Gao

We examine the gain property of a probe field interacting with two different three-level Lambda-type atomic systems with an open loop or a close loop. In the atomic system with an open loop, there exists quantum interference resulting from spontaneous emissions to two near-degenerate lower levels from a common upper level, and the weak probe field can be greatly amplified due to the spontaneously generated coherence. Moreover, the probe gain becomes sensitive to the relative phase between the probe and coupling fields, so we can realize phase control of the probe gain in principle. In the atomic system with a close loop, we use a microwave field to couple the two well-spaced lower levels so that quantum coherence similar to SGC can be generated. In this atomic system, we also can achieve the phase-sensitive probe gain due to the quantum interference between two different absorption channels for the probe field. Note, only in the case of three-photon resonance, this close-loop atomic system can reach a steady state. While in the case of three-photon off-resonance, the probe gain without inversion always oscillates periodically versus time, thus no steady-state probe gain can be achieved.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Jan 11, 2005•0 citations
We have studied the amplification of a single-mode electromagnetic field by an atomic system with a three-level cascade structure in two-photon resonance conditions when the top and bottom levels are mixed coherently by a strong external resonant field. We find different kinds of phase-sensitive amplification for different values of the driving field strength. For a very high driving field and near one-photon resonance, the system approaches an ideal parametric amplifier.
A linear theory of two-photon amplification by three-level atoms in the cascade configuration is developed, where a coherence is induced between the top and bottom levels, by an external classical driving field. It is shown that this system becomes an ideal parametric amplifier for sufficiently strong driving field, whereas for a weak driving field it is a phase-insensitive amplifier. In between these two extremes, one finds phase-sensitive amplification as well as squeezing for a certain range. The system does not, however, reduce to a model studied previously where the atomic coherence was treated as an initial condition. The system is also studied in a cavity configuration: It is predicted that the oscillator may behave as a two-photon correlated emission laser, i.e., its phase diffusion coefficient vanishes.
A theory of two-mode phase-sensitive amplification by a three-level atomic system in the cascade configuration is presented, within the framework of the theory of multiwave mixing. Two photons of a strong external pump field induce coherence between the top and bottom levels. It is shown that both quadratures of the field modes acquire unequal gain and added noise. For large values of the dimensionless pump intensity, with a particular choice of its phase, and zero side-mode detuning, the system behaves as a nondegenerate parametric amplifier.
Phase-sensitive amplification in a three-level atomic system exhibits interesting features. For example, in the zero-detuning limit and for sufficiently strong driving field, this system becomes an ideal parametric amplifier, whereas, for a weak driving field it is a phase-insensitive amplifier [Ansari et al., Phys. Rev. A 41, 5179 (1990)]. In this paper, we show that this system could be used to measure the quantum state of the radiation field inside a cavity. To reconstruct the quantum state, we amplify it through a three-level atomic system and in the parametric limit, when noise in both the quadratures approaches to zero measure the amplified field quadrature. The complete quadrature distribution is obtained by measuring the quadratures for different values of the driving field phases. The inverse Radon transformation is then employed to reconstruct the original quantum state. Our scheme is insensitive to the problems associated with nonunit detector efficiency in homodyne detection measurement.
We examine the gain property of a probe field interacting with two different three-level Lambda-type atomic systems with an open loop or a close loop. In the atomic system with an open loop, there exists quantum interference resulting from spontaneous emissions to two near-degenerate lower levels from a common upper level, and the weak probe field can be greatly amplified due to the spontaneously generated coherence. Moreover, the probe gain becomes sensitive to the relative phase between the probe and coupling fields, so we can realize phase control of the probe gain in principle. In the atomic system with a close loop, we use a microwave field to couple the two well-spaced lower levels so that quantum coherence similar to SGC can be generated. In this atomic system, we also can achieve the phase-sensitive probe gain due to the quantum interference between two different absorption channels for the probe field. Note, only in the case of three-photon resonance, this close-loop atomic system can reach a steady state. While in the case of three-photon off-resonance, the probe gain without inversion always oscillates periodically versus time, thus no steady-state probe gain can be achieved.