TY - JOUR

T1 - Atomic-motion-induced spectroscopic effects that are nonlinear in atomic density in a gas

AU - Yudin, V. I.

AU - Taichenachev, A. V.

AU - Basalaev, M. Y.U.

AU - Prudnikov, O. N.

AU - Bagayev, S. N.

N1 - Funding Information: Russian Science Foundation (21-12-00057). We thank I. M. Sokolov, V. L. Velichansky, and J. W. Pollock for useful discussions and comments. Publisher Copyright: © 2022 Optica Publishing Group.

PY - 2022/7

Y1 - 2022/7

N2 - The interatomic dipole–dipole interaction is commonly thought to be the main physical reason for spectroscopic effects, which are nonlinear in atomic density. However, we have found that the free motion of atoms can lead to other effects that are nonlinear in atomic density n, using a previously unknown self-consistent solution of the Maxwell–Bloch equations in the mean-field approximation for a gas of two-level atoms with an optical transition at unperturbed frequency ω0. These effects distort the Doppler lineshape (shift, asymmetry, broadening), but are not associated with an atom–atom interaction. In particular, in the case of nk0−3 < 1 (where k0 = ω0/c) and significant Doppler broadening (with respect to collisional broadening), atomic-motion-induced nonlinear effects significantly exceed the well-known influence of the dipole–dipole interatomic interaction (e.g., Lorentz–Lorenz shift) by more than one order of magnitude. Moreover, under some conditions, a frequency interval appears in which a non-trivial self-consistent solution of the Maxwell–Bloch equations is absent due to atomic motion effects. Thus, the existing physical picture of spectroscopic effects that are nonlinear in atomic density in a gas medium should be substantially revised.

AB - The interatomic dipole–dipole interaction is commonly thought to be the main physical reason for spectroscopic effects, which are nonlinear in atomic density. However, we have found that the free motion of atoms can lead to other effects that are nonlinear in atomic density n, using a previously unknown self-consistent solution of the Maxwell–Bloch equations in the mean-field approximation for a gas of two-level atoms with an optical transition at unperturbed frequency ω0. These effects distort the Doppler lineshape (shift, asymmetry, broadening), but are not associated with an atom–atom interaction. In particular, in the case of nk0−3 < 1 (where k0 = ω0/c) and significant Doppler broadening (with respect to collisional broadening), atomic-motion-induced nonlinear effects significantly exceed the well-known influence of the dipole–dipole interatomic interaction (e.g., Lorentz–Lorenz shift) by more than one order of magnitude. Moreover, under some conditions, a frequency interval appears in which a non-trivial self-consistent solution of the Maxwell–Bloch equations is absent due to atomic motion effects. Thus, the existing physical picture of spectroscopic effects that are nonlinear in atomic density in a gas medium should be substantially revised.

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UR - https://www.mendeley.com/catalogue/0b11c244-7b57-32c6-9dcb-50326c71329d/

U2 - 10.1364/JOSAB.456131

DO - 10.1364/JOSAB.456131

M3 - Article

AN - SCOPUS:85137555057

VL - 39

SP - 1979

EP - 1985

JO - Journal of the Optical Society of America B: Optical Physics

JF - Journal of the Optical Society of America B: Optical Physics

SN - 0740-3224

IS - 7

ER -