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

Journal of the Physical Society of Japan

Laser Cooling, Friction and Diffusion in Three-Level Cascade System in Squeezed Vacuum

Lei Tan, Cuiling Zhang, Jinfang Zhang, Xiao-Fei Zang, Juping Li

Published Sep 11, 2006• 0 citations
Publisher

Abstract

A theoretical study is carried out for the laser cooling of a moving three-level atom in a ladder configuration, driven by a bichromatic laser fields with a broad-band squeezed vacuum. The friction, diffusion coefficients and the equilibrium temperature are calculated numerically and shown graphically as a function of two-photon detunings for various cases of the squeezed vacuum. It is shown that the relative phases between the two coherent fields and the squeezed vacuum field play an important role in the cooling process. For a suitable choice of parameters, the atomic cooling temperature may be reduced to below that in the case of a vacuum, even down to two orders below the Doppler temperature limit. The efficiency of this cooling scheme is also analyzed.

DOI
10.1143/jpsj.75.094301

Related papers

Radiation pressure and laser cooling of a three-level atom in a ladder configuration

Lei Tan, Wang Zhicheng, Huai-Qiang Gu

Radiation pressure and laser cooling of a moving three-level ladder-type atom in bichromatic travelling fields are considered. The dependence of the force on parameters such as detunings, Rabi frequencies and spontaneous decay rates is calculated numerically and shown graphically and analytical expressions for the force are obtained for some special parameter values. It is shown that the radiation pressure shows Doppler-shifted resonance peaks resulting respectively from one-photon and two-photon transitions. Using the present scheme, Doppler cooling of sodium exploiting the 3 2 S 1/2 –3 2 P 3/2 –3 2 D 5/2 cascade transitions is investigated. It is found that temperatures lower than the Doppler limit can be achieved.

Chinese Physics•Jun 30, 2004•2 citations

Laser cooling, friction, and diffusion in a three-level cascade system

Wilbert Rooijakkers, W. Hogervorst, W. Vassen

A model is presented to calculate optical forces, friction, and diffusion for three-level atoms in a ladder configuration. This model is then applied to the ${2}^{3}{S}_{1}{\ensuremath{-}2}^{3}{P}_{2}{\ensuremath{-}3}^{3}{D}_{3}$ cascade in metastable helium. It is demonstrated that metastable helium atoms can be decelerated within a much shorter distance using cascade excitation by overlapping traveling waves. The equilibrium temperature representing the final width of the velocity distribution is calculated as a function of laser detuning and intensity. This equilibrium temperature is also calculated for the situation of overlapping standing waves (one-dimension), and is found to be well above the Doppler limit for two-level ${2}^{3}{S}_{1}{\ensuremath{-}2}^{3}{P}_{2}$ excitation. Numerical results are compared with existing experimental data.

Physical Review A•Oct 1, 1997•19 citations

Dissipative Force and Laser Cooling of a Ladder-Type Three-Level Atom

Z. C. Wang, Lei Tan

A theoretical study is made of the dissipative force and Doppler cooling of a ladder-type three-level atom coupled to a travelling coherent light beam. The dependence of the force on parameters such as detunings, Rabi frequencies, spontaneous decay and coherence transfer rates is calculated numerically and shown graphically. Analytical expressions for the force are obtained for special parameter values. It is shown that for suitable choices of parameter values, it is possible to cool three-level atoms to temperatures down below the Doppler limit.

Journal of the Physical Society of Japan•Sep 15, 2003•3 citations

Laser cooling of a moving atom in a bichromatical travelling field

Lei Tan, Zhang Rui Qin

A theoretical study is made of the Doppler cooling of a moving three-level atom coupled to bichromatical traveling fields.The dependences of the equilibrium temperature of the atom on two-photon detunings are calculated numerically under conditions of different laser intensity,frequencies and propaga- tional direction.It is shown that temperatures lower than the one in the one-photon processes can be achieved in the enhancement of the two-photon processes.

Journal of Lanzhou University•Jan 1, 2006•0 citations

Photon Absorptions of a Driven Three-Level Atom in a Squeezed Vacuum

Zhaoyang Chen, Yan Xu, Zhi‐Cheng Wang

A three-level ladder atom driven by two coherent laser fields with rather different frequencies in various kinds of reservoirs is considered. Making use of the master equation and Bloch equation, we calculate numerically and show graphically the steady-state populations versus two-photon detuning. We also discuss and compare the two-photon and one-photon processes occurring for various cases. For a squeezed vacuum, only when the carrier frequency of the squeezed vacuum equals the average of frequencies of the two driving fields and the phase matching condition is fulfilled, will there be a strong two-photon resonant absorption from the squeezed vacuum, a characteristic different from absorption of photons from a classical field; Otherwise, the two-photon ab-sorption rate from the squeezed vacuum will be greatly diminished.

Journal of the Physical Society of Japan•Aug 15, 1998•0 citations

Steady-State Population of a Moving Ladder-Type Three-Level Atom in Broad-Band Squeezed Vacuum

Yuan Hai-liang

This paper mainly deals with the steady-state population of a moving ladder-type three-level atom,driven by a superposition of a monochromatic laser wave with a broad-band squeezed vacuum,From the Hamiltonian of the atomic system,making use of Born-Markoff approximation,we derive the master equation for the system and the atomic Bloch equations and obtain the steady-state solutions of the optical Bloch equations using numerical calculation.Then we discuss the dependence of the attained population σ_(ii) on parameters such as detuning Δ,Rabi frequencies e_1e_2,phase ,squeezing photon number N and spontaneous decay ratesγ_1 γ_2 etc in different cases by using graphical method.

Journal of Qinghai Normal University•Jan 1, 2006•0 citations
A theoretical study is carried out for the laser cooling of a moving three-level atom in a ladder configuration, driven by a bichromatic laser fields with a broad-band squeezed vacuum. The friction, diffusion coefficients and the equilibrium temperature are calculated numerically and shown graphically as a function of two-photon detunings for various cases of the squeezed vacuum. It is shown that the relative phases between the two coherent fields and the squeezed vacuum field play an important role in the cooling process. For a suitable choice of parameters, the atomic cooling temperature may be reduced to below that in the case of a vacuum, even down to two orders below the Doppler temperature limit. The efficiency of this cooling scheme is also analyzed.
Radiation pressure and laser cooling of a moving three-level ladder-type atom in bichromatic travelling fields are considered. The dependence of the force on parameters such as detunings, Rabi frequencies and spontaneous decay rates is calculated numerically and shown graphically and analytical expressions for the force are obtained for some special parameter values. It is shown that the radiation pressure shows Doppler-shifted resonance peaks resulting respectively from one-photon and two-photon transitions. Using the present scheme, Doppler cooling of sodium exploiting the 3 2 S 1/2 –3 2 P 3/2 –3 2 D 5/2 cascade transitions is investigated. It is found that temperatures lower than the Doppler limit can be achieved.
A model is presented to calculate optical forces, friction, and diffusion for three-level atoms in a ladder configuration. This model is then applied to the ${2}^{3}{S}_{1}{\ensuremath{-}2}^{3}{P}_{2}{\ensuremath{-}3}^{3}{D}_{3}$ cascade in metastable helium. It is demonstrated that metastable helium atoms can be decelerated within a much shorter distance using cascade excitation by overlapping traveling waves. The equilibrium temperature representing the final width of the velocity distribution is calculated as a function of laser detuning and intensity. This equilibrium temperature is also calculated for the situation of overlapping standing waves (one-dimension), and is found to be well above the Doppler limit for two-level ${2}^{3}{S}_{1}{\ensuremath{-}2}^{3}{P}_{2}$ excitation. Numerical results are compared with existing experimental data.
A theoretical study is made of the dissipative force and Doppler cooling of a ladder-type three-level atom coupled to a travelling coherent light beam. The dependence of the force on parameters such as detunings, Rabi frequencies, spontaneous decay and coherence transfer rates is calculated numerically and shown graphically. Analytical expressions for the force are obtained for special parameter values. It is shown that for suitable choices of parameter values, it is possible to cool three-level atoms to temperatures down below the Doppler limit.
A three-level ladder atom driven by two coherent laser fields with rather different frequencies in various kinds of reservoirs is considered. Making use of the master equation and Bloch equation, we calculate numerically and show graphically the steady-state populations versus two-photon detuning. We also discuss and compare the two-photon and one-photon processes occurring for various cases. For a squeezed vacuum, only when the carrier frequency of the squeezed vacuum equals the average of frequencies of the two driving fields and the phase matching condition is fulfilled, will there be a strong two-photon resonant absorption from the squeezed vacuum, a characteristic different from absorption of photons from a classical field; Otherwise, the two-photon ab-sorption rate from the squeezed vacuum will be greatly diminished.
This paper mainly deals with the steady-state population of a moving ladder-type three-level atom,driven by a superposition of a monochromatic laser wave with a broad-band squeezed vacuum,From the Hamiltonian of the atomic system,making use of Born-Markoff approximation,we derive the master equation for the system and the atomic Bloch equations and obtain the steady-state solutions of the optical Bloch equations using numerical calculation.Then we discuss the dependence of the attained population σ_(ii) on parameters such as detuning Δ,Rabi frequencies e_1e_2,phase ,squeezing photon number N and spontaneous decay ratesγ_1 γ_2 etc in different cases by using graphical method.