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

Acta Physica Sinica

Enhanced Kerr nonlinear effect of Raman transition in a Λ-type three-level atomic system

Haibin Wu, Chang Hong, Ma Jie, Changde Xie, Wang Hai, 山西大学光电研究所，量子光学与光量子器件国家重点实验室，太原 030006

Published Jan 1, 2005• 3 citations
Publisher

Abstract

We report a theoretical study of linear and nonlinear susceptibilities of Raman transition in a Λ-type three-level atomic system. In the Raman transition, if t he population of atoms is all prepared in the ground state which interacts with the control light, the linear susceptibility equals zero, while the third-order nonlinear susceptibility does not equal zero. By decreasing the nonradiative dec ay rate γ12 between the two ground states of the atoms, the Kerr no nlinear refractive index for cross-phase modulation can be significantly enhance d.

DOI
10.7498/aps.54.3632

Related papers

Enhancement of Third-Order Self-Kerr Nonlinearity and Cross-Kerr Nonlinearity in Three-Level Atomic systems

Liu Zhi-Yuan, Yupeng Duan, Ying-Jie Du

Abstract We theoretically investigate the self-nonlinear and cross-nonlinear responses of the Λ-type, V-type, and ladder-type three-level atomic systems. The analytical solutions of the cross-nonlinearity are obtained by using an iterative method. These analytical expressions reveal that the atomic decay rates and two-photon resonance are closely related to the cross-nonlinear response. For the Λ-type system, the relaxation rate between the ground-state sublevels determines the amplitude and linewidth of the cross-nonlinearity. For the ladder-type system, the lifetime of the upper excited state governs the amplitude and linewidth of the cross-nonlinearity. In both systems, the amplitude of the cross-nonlinearity is significantly enhanced, and the linewidth is greatly compressed simultaneously. In contrast, for the V-type three-level system, the amplitude and linewidth of the cross-nonlinearity are related to the spontaneous emission rate of the excited states, where neither the amplitude enhancement nor the linewidth compression is observed. We conclude that the cross-nonlinear response can reach or even exceed the linear response in the Λ-type system when the relaxation rate between the ground states is sufficiently small, or in the ladder-type system when the spontaneous emission rate of the upper excited state is sufficiently small. Compared with the crossnonlinearity, the self-nonlinearity is related to the Rabi frequency and detuning of the coupling field. Its amplitude decreases with the increase of the coupling Rabi frequency, while it can be increased to a certain extent with the increase of the coupling detuning. Our results provide a theoretical basis for the optimization and application of strong nonlinear effects in three-level atomic systems.

Chinese Physics B•May 20, 2026•0 citations

Phase-sensitive Kerr nonlinearity for closed-loop quantum systems

Hamid Reza Hamedi, Gediminas Juzeliūnas

The third-order susceptibility is investigated in a five-level atomic system in which the laser beams couple the ground state to a four-level closed-loop system. It is found that under the condition of the multiphoton resonance, one can enhance the Kerr nonlinearity of such a medium by properly adjusting the amplitudes and phases of the applied fields. In this case, the linear and nonlinear absorption reduce considerably in a region with a positive group velocity. It is demonstrated that the third-order susceptibility is very sensitive to the relative phase of the applied fields. An analytical model is presented to elucidate such phase control of the Kerr nonlinearity. A comparison is also made between the Kerr-nonlinear indices for the five-, four-, and three-level systems. It is realized that the magnitude of the Kerr nonlinearity for the five-level system is larger than that of the three- and four-level counterparts. Finally, it is shown that effect of Doppler broadening can lead to an enhanced Kerr nonlinearity while maintaining linear and nonlinear absorption.

Physical Review A•May 14, 2015•94 citations

Enhanced Kerr nonlinearity for self-action via atomic coherence in a four-level atomic system

Hong, T, Jack, M W, Yamashita, M +1 more

Enhancement of optical Kerr nonlinearity for self-action by electro-magnetically induced transparency in a four-level atomic system including dephasing between the ground states is studied in detail by solving the density matrix equations for the atomic levels. We discern three major contributions, from energy shifts of the ground states induced by the probe light, to the third-order susceptibility in the four-level system. In this four-level system with the frequency-degenerate probes, quantum interference amongst the three contributions can, not only enhance the third-order susceptibility more effectively than in the three-level system with the same characteristic parameters, but also make the ratio between its real and imaginary part controllable. Due to dephasing between the two ground states and constructive quantum interference, the most effective enhancement generally occurs at an offset that is determined by the atomic transition frequency difference and the coupling Rabi frequency.

•Nov 1, 2002•15 citations

Polychromatic Kerr nonlinearity within electromagnetically induced transparency window

Guanghui Wang, Chuan-Jia Shan, De-Ying Gao +3 more

We study the nonlinear effect in a three-level atomic system in Λ configuration. As two or more fields are confined within the common electromagnetically induced transparency (EIT) window, they directly disturb EIT dark state at the same time, which leads to the self- and cross-Kerr nonlinear interactions. Our scheme is different from the existed schemes based on three-level or multilevel systems only existing single type of nonlinear interactions. In the common EIT windows, the self- and cross-Kerr nonlinearities are established with suppressed linear absorption and our scheme can be generalized polychromatic Kerr nonlinearity. Because the atoms are almost trapped in the ground states and the atom population becomes unchanged, the scheme is robust to the atomic spontaneous emission. Our scheme is a promising avenue for preparation of squeezing and entanglement .

Results in Physics•Oct 1, 2021•6 citations

Effective cross-Kerr nonlinearity in a Raman resonant of four-level atom

Li Yongfang

A theoretical investigation is put forward for obtaining effective cross-Kerr nonlinearity of the four-level atom interacting with three electromagnetic fields.Using density-matrix equations and perturbation iterative method,the variation dependence of the third-order susceptibility on the detunings of the applied electromagnetic fields is derived.The results show that a large cross-Kerr nonlinearity can be generated when the detunings of the two weak probe fields are Raman resonant,and the corresponding linear susceptibility and self-Kerr interactions vanish.The realization of the effective Kerr nonlinearity with vanishing absorption is possible in a Raman resonant four-level system.

Journal of Shaanxi Normal University•Jan 1, 2011•0 citations

All-optical switching via enhanced Kerr nonlinearity in three-level atoms

Hai Wang, David J. Goorskey, Min Xiao

Summary form only given. The reduced absorption and enhanced nonlinearity in a three-level electromagnetically induced transparency (EIT) system are very important in achieving an effective all-optical switching action. The Kerr-nonlinear index of refraction of a three-level EIT medium can be greatly enhanced near resonance due to atomic coherence induced in such a system in comparison with a two-level atomic system, as we have shown by using an optical ring cavity. Both the magnitude and sign of the Kerr-nonlinear index change dramatically for different frequency detunings of the controlling (or coupling) or cavity (or probe) field. Bistability and dynamic instability occur when such a three-level /spl Lambda/-type EIT system is placed inside an optical ring cavity and the controlling and cavity input intensities to exceed certain threshold values. In this paper, we present a recent experimental demonstration of controlling the cavity output intensity by modulating the frequency detuning of the controlling beam.

Quantum Electronics and Laser Science Conference•Jun 25, 2003•0 citations
We report a theoretical study of linear and nonlinear susceptibilities of Raman transition in a Λ-type three-level atomic system. In the Raman transition, if t he population of atoms is all prepared in the ground state which interacts with the control light, the linear susceptibility equals zero, while the third-order nonlinear susceptibility does not equal zero. By decreasing the nonradiative dec ay rate γ12 between the two ground states of the atoms, the Kerr no nlinear refractive index for cross-phase modulation can be significantly enhance d.
Abstract We theoretically investigate the self-nonlinear and cross-nonlinear responses of the Λ-type, V-type, and ladder-type three-level atomic systems. The analytical solutions of the cross-nonlinearity are obtained by using an iterative method. These analytical expressions reveal that the atomic decay rates and two-photon resonance are closely related to the cross-nonlinear response. For the Λ-type system, the relaxation rate between the ground-state sublevels determines the amplitude and linewidth of the cross-nonlinearity. For the ladder-type system, the lifetime of the upper excited state governs the amplitude and linewidth of the cross-nonlinearity. In both systems, the amplitude of the cross-nonlinearity is significantly enhanced, and the linewidth is greatly compressed simultaneously. In contrast, for the V-type three-level system, the amplitude and linewidth of the cross-nonlinearity are related to the spontaneous emission rate of the excited states, where neither the amplitude enhancement nor the linewidth compression is observed. We conclude that the cross-nonlinear response can reach or even exceed the linear response in the Λ-type system when the relaxation rate between the ground states is sufficiently small, or in the ladder-type system when the spontaneous emission rate of the upper excited state is sufficiently small. Compared with the crossnonlinearity, the self-nonlinearity is related to the Rabi frequency and detuning of the coupling field. Its amplitude decreases with the increase of the coupling Rabi frequency, while it can be increased to a certain extent with the increase of the coupling detuning. Our results provide a theoretical basis for the optimization and application of strong nonlinear effects in three-level atomic systems.
The third-order susceptibility is investigated in a five-level atomic system in which the laser beams couple the ground state to a four-level closed-loop system. It is found that under the condition of the multiphoton resonance, one can enhance the Kerr nonlinearity of such a medium by properly adjusting the amplitudes and phases of the applied fields. In this case, the linear and nonlinear absorption reduce considerably in a region with a positive group velocity. It is demonstrated that the third-order susceptibility is very sensitive to the relative phase of the applied fields. An analytical model is presented to elucidate such phase control of the Kerr nonlinearity. A comparison is also made between the Kerr-nonlinear indices for the five-, four-, and three-level systems. It is realized that the magnitude of the Kerr nonlinearity for the five-level system is larger than that of the three- and four-level counterparts. Finally, it is shown that effect of Doppler broadening can lead to an enhanced Kerr nonlinearity while maintaining linear and nonlinear absorption.
Enhancement of optical Kerr nonlinearity for self-action by electro-magnetically induced transparency in a four-level atomic system including dephasing between the ground states is studied in detail by solving the density matrix equations for the atomic levels. We discern three major contributions, from energy shifts of the ground states induced by the probe light, to the third-order susceptibility in the four-level system. In this four-level system with the frequency-degenerate probes, quantum interference amongst the three contributions can, not only enhance the third-order susceptibility more effectively than in the three-level system with the same characteristic parameters, but also make the ratio between its real and imaginary part controllable. Due to dephasing between the two ground states and constructive quantum interference, the most effective enhancement generally occurs at an offset that is determined by the atomic transition frequency difference and the coupling Rabi frequency.
We study the nonlinear effect in a three-level atomic system in Λ configuration. As two or more fields are confined within the common electromagnetically induced transparency (EIT) window, they directly disturb EIT dark state at the same time, which leads to the self- and cross-Kerr nonlinear interactions. Our scheme is different from the existed schemes based on three-level or multilevel systems only existing single type of nonlinear interactions. In the common EIT windows, the self- and cross-Kerr nonlinearities are established with suppressed linear absorption and our scheme can be generalized polychromatic Kerr nonlinearity. Because the atoms are almost trapped in the ground states and the atom population becomes unchanged, the scheme is robust to the atomic spontaneous emission. Our scheme is a promising avenue for preparation of squeezing and entanglement .
A theoretical investigation is put forward for obtaining effective cross-Kerr nonlinearity of the four-level atom interacting with three electromagnetic fields.Using density-matrix equations and perturbation iterative method,the variation dependence of the third-order susceptibility on the detunings of the applied electromagnetic fields is derived.The results show that a large cross-Kerr nonlinearity can be generated when the detunings of the two weak probe fields are Raman resonant,and the corresponding linear susceptibility and self-Kerr interactions vanish.The realization of the effective Kerr nonlinearity with vanishing absorption is possible in a Raman resonant four-level system.
Summary form only given. The reduced absorption and enhanced nonlinearity in a three-level electromagnetically induced transparency (EIT) system are very important in achieving an effective all-optical switching action. The Kerr-nonlinear index of refraction of a three-level EIT medium can be greatly enhanced near resonance due to atomic coherence induced in such a system in comparison with a two-level atomic system, as we have shown by using an optical ring cavity. Both the magnitude and sign of the Kerr-nonlinear index change dramatically for different frequency detunings of the controlling (or coupling) or cavity (or probe) field. Bistability and dynamic instability occur when such a three-level /spl Lambda/-type EIT system is placed inside an optical ring cavity and the controlling and cavity input intensities to exceed certain threshold values. In this paper, we present a recent experimental demonstration of controlling the cavity output intensity by modulating the frequency detuning of the controlling beam.