Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review A

Excess noise correlation using population-trapped atoms

Maneesh Jain

Published Aug 1, 1994• 11 citations
Publisher

Abstract

We study the behavior of two quantized fields interacting with atoms in a coherent population-trapped state. It has recently been shown that such a system generates fields with matched envelopes as well as matched photon statistics. These effects have an important consequence: the matching of any excess noise input at the two channels of the system. We explicitly show the generation of correlated excess noise by a population-trapped atomic system and how this effect may be used to suppress the excess noise and enhance the carrier-to-noise ratio of optical sources.

DOI
10.1103/physreva.50.1899

Related papers

Coherent population trapping states of a system interacting with quantized fields and the production of the photon statistics matched fields

G. S. Agarwal

I calculate the coherent population trapping states of a three-level system interacting with two quantized fields. I show that such trapping states have novel properties. For example, I show that the trapping states for a \ensuremath{\Lambda} system involve the production of radiation fields with matched photon statistics. I discuss a method for producing these trapping states. For a ladder system, the trapping states even lead to the nonclassical character of the radiation fields.

Physical Review Letters•Aug 30, 1993•101 citations

Excess optical quantum noise in atomic sensors

Irina V. Novikova, Eugeniy E. Mikhailov, Yanhong Xiao

Enhanced nonlinear optical response of a coherent atomic medium is the basis for many atomic sensors, and their performance is ultimately limited by the quantum fluctuations of the optical readout. Here we demonstrate that the off-resonant interactions, with the aid of the near-resonant process, can significantly modify the quantum noise of a coherent light field, even when its effect on the mean signal is negligible. The altered quantum optical noise distribution results in excess noise in the measurement quantity. We illustrate this concept by using an atomic magnetometer based on the nonlinear Faraday effect. These results show the existence of previously unnoticed factors in fundamental limitations in atomic magnetometry and could have impact in a wide range of atom-light--based precision measurements.

arXiv:1410.3810•Physical Review A•May 22, 2015•17 citations

Optical-density-enhanced squeezed-light generation without optical cavities

You-Lin Chuang, Ray‐Kuang Lee, Ite A. Yu

To achieve a high degree of quantum noise squeezing, an optical cavity is often employed to enhance the interaction time between light and matter. Here, we propose to utilize the effect of coherent population trapping (CPT) to directly generate squeezed light without any optical cavity. Combined with the slow propagation speed of light in a CPT medium, a coherent state passing through an atomic ensemble with a high optical density (OD) can evolve into a highly squeezed state even in a single passage. Our study reveals that noise squeezing of more than 10 dB can be achieved with an OD of 1000, which is currently available in experiments. A larger OD can further increase the degree of squeezing. As the light intensity and two-photon detuning are key factors in the CPT interaction, we also demonstrate that the minimum variance at a given OD can be reached for a wide range of these two factors, showing the proposed scheme is flexible and robust. Furthermore, there is no need to consider the phase-matching condition in the CPT scheme. Our introduction of high OD in atomic media not only brings a long light-matter interaction time comparable to optical cavities, but also opens an alternative avenue in the generation of squeezed light for quantum interface.

arXiv:1703.09890•Physical Review A•Nov 8, 2017•13 citations

Population trapping with quantized fields in two-channel models of atomic excitation

Christopher C. Gerry

In this paper, we study several models of two-channel atomic excitation involving quantized fields and search for field states that result in the trapping of the atomic population in a single bare state. This trapping is a result of quantum interference between the two channels. We study the following models: a two-level atom resonantly interacting with two quantized field modes, a two-level atom with competing one and three photon transitions, and a Raman coupled model containing both Stokes and anti-Stokes fields. We find a great variety of trapping states of the field, some of the states being highly non-classical. The effects of dissipation on the stability of the trapping states are discussed and a method for generating some of the states is presented.

Journal of Modern Optics•Nov 1, 1999•4 citations

Simultaneous squeezing of coherent fields using coherent population trapping

Qing Yang Xu, Xing Ming, Hongliang Deng +5 more

We study the effects of equal and unequal Rabi frequencies as well as cavity bandwidth on the optimal noise of the output fields from a two-mode optical cavity, which is fed by two coherent fields and encloses a collection of three-level Λ atoms. Each of the output modes is shown to be highly squeezed in the case of smaller symmetrical atomic detunings compared to the spontaneous-emission rates, where the system is in the vicinity of perfect coherent population trapping (CPT). We find that the squeezing on each output mode is larger than that reported by Dantan et al (2006 Phys. Rev. Lett. 97 023605) when adjusting the equal Rabi frequencies. The cavity bandwidth affects, not the degree of squeezing, but the linewidth of the spectral components. In an alternative way, the squeezing of each outgoing mode can be understood as a consequence of the enhanced cross-phase modulation, different from the nonlinear Faraday effect in Dantan's paper (2006 Phys. Rev. Lett. 97 023605). The application of squeezed light is to obtain high-precision measurement, optical communication, and interferometric detection of gravitational radiation.

Laser Physics•Nov 14, 2014•6 citations

Controlling the quantum noise of intense light

Nicholas Rivera

In reality, a wide variety of laser sources have fluctuations in excess (and often far in excess) of the coherent state, even when technical noise sources are suppressed. I present recent advances that challenge this paradigm, and show how multimode nonlinearities can be steered towards reducing the noise of intense beams of light down to quantum limits associated with coherent states and squeezed states of light. I will show how multimode correlations and wavefront shaping can suppress excess noise by orders of magnitude: reaching, and even surpassing, the shot-noise limit. We demonstrate these effects for femtosecond pulses propagating in both single-mode fibers and in multi-mode fibers. Our ability to control noise is aided by a general theory framework that we have developed, called quantum sensitivity analysis, which lets us predict how quantum noise is transformed by nonlinear and multimode systems.

Nonlinear Frequency Generation and Conversion: Materials and Devices•Mar 4, 2026•0 citations
We study the behavior of two quantized fields interacting with atoms in a coherent population-trapped state. It has recently been shown that such a system generates fields with matched envelopes as well as matched photon statistics. These effects have an important consequence: the matching of any excess noise input at the two channels of the system. We explicitly show the generation of correlated excess noise by a population-trapped atomic system and how this effect may be used to suppress the excess noise and enhance the carrier-to-noise ratio of optical sources.
Enhanced nonlinear optical response of a coherent atomic medium is the basis for many atomic sensors, and their performance is ultimately limited by the quantum fluctuations of the optical readout. Here we demonstrate that the off-resonant interactions, with the aid of the near-resonant process, can significantly modify the quantum noise of a coherent light field, even when its effect on the mean signal is negligible. The altered quantum optical noise distribution results in excess noise in the measurement quantity. We illustrate this concept by using an atomic magnetometer based on the nonlinear Faraday effect. These results show the existence of previously unnoticed factors in fundamental limitations in atomic magnetometry and could have impact in a wide range of atom-light--based precision measurements.
To achieve a high degree of quantum noise squeezing, an optical cavity is often employed to enhance the interaction time between light and matter. Here, we propose to utilize the effect of coherent population trapping (CPT) to directly generate squeezed light without any optical cavity. Combined with the slow propagation speed of light in a CPT medium, a coherent state passing through an atomic ensemble with a high optical density (OD) can evolve into a highly squeezed state even in a single passage. Our study reveals that noise squeezing of more than 10 dB can be achieved with an OD of 1000, which is currently available in experiments. A larger OD can further increase the degree of squeezing. As the light intensity and two-photon detuning are key factors in the CPT interaction, we also demonstrate that the minimum variance at a given OD can be reached for a wide range of these two factors, showing the proposed scheme is flexible and robust. Furthermore, there is no need to consider the phase-matching condition in the CPT scheme. Our introduction of high OD in atomic media not only brings a long light-matter interaction time comparable to optical cavities, but also opens an alternative avenue in the generation of squeezed light for quantum interface.
In this paper, we study several models of two-channel atomic excitation involving quantized fields and search for field states that result in the trapping of the atomic population in a single bare state. This trapping is a result of quantum interference between the two channels. We study the following models: a two-level atom resonantly interacting with two quantized field modes, a two-level atom with competing one and three photon transitions, and a Raman coupled model containing both Stokes and anti-Stokes fields. We find a great variety of trapping states of the field, some of the states being highly non-classical. The effects of dissipation on the stability of the trapping states are discussed and a method for generating some of the states is presented.
We study the effects of equal and unequal Rabi frequencies as well as cavity bandwidth on the optimal noise of the output fields from a two-mode optical cavity, which is fed by two coherent fields and encloses a collection of three-level Λ atoms. Each of the output modes is shown to be highly squeezed in the case of smaller symmetrical atomic detunings compared to the spontaneous-emission rates, where the system is in the vicinity of perfect coherent population trapping (CPT). We find that the squeezing on each output mode is larger than that reported by Dantan et al (2006 Phys. Rev. Lett. 97 023605) when adjusting the equal Rabi frequencies. The cavity bandwidth affects, not the degree of squeezing, but the linewidth of the spectral components. In an alternative way, the squeezing of each outgoing mode can be understood as a consequence of the enhanced cross-phase modulation, different from the nonlinear Faraday effect in Dantan's paper (2006 Phys. Rev. Lett. 97 023605). The application of squeezed light is to obtain high-precision measurement, optical communication, and interferometric detection of gravitational radiation.
In reality, a wide variety of laser sources have fluctuations in excess (and often far in excess) of the coherent state, even when technical noise sources are suppressed. I present recent advances that challenge this paradigm, and show how multimode nonlinearities can be steered towards reducing the noise of intense beams of light down to quantum limits associated with coherent states and squeezed states of light. I will show how multimode correlations and wavefront shaping can suppress excess noise by orders of magnitude: reaching, and even surpassing, the shot-noise limit. We demonstrate these effects for femtosecond pulses propagating in both single-mode fibers and in multi-mode fibers. Our ability to control noise is aided by a general theory framework that we have developed, called quantum sensitivity analysis, which lets us predict how quantum noise is transformed by nonlinear and multimode systems.