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

arXiv:1308.5590 · Physical Review Letters

Optics of a Gas of Coherently Spinning Molecules

Uri Steinitz, Yehiam Prior, Ilya Sh. Averbukh

Published Jan 10, 2014• 33 citations
arXivHTMLPDF

Abstract

We consider the optical properties of a gas of molecules that are brought to fast unidirectional spinning by a pulsed laser field. It is shown that a circularly polarized probe light passing through the medium inverts its polarization handedness and experiences a frequency shift controllable by the sense and the rate of molecular rotation. Our analysis is supported by two recent experiments on the laser-induced rotational Doppler effect in molecular gases and provides a good qualitative and quantitative description of the experimental observations.

DOI
10.1103/physrevlett.112.013004

Related papers

Controlling the sense of molecular rotation

Sharly Fleischer, Yuri Khodorkovsky, Yehiam Prior +1 more

We introduce a new scheme for controlling the sense of molecular rotation. By varying the polarization and the delay between two ultrashort laser pulses, we induce unidirectional molecular rotation, thereby forcing the molecules to rotate clockwise/counterclockwise under field-free conditions. We show that unidirectionally rotating molecules are confined to the plane defined by the two polarization vectors of the pulses, which leads to a permanent anisotropy in the molecular angular distribution. The latter may be useful for controlling collisional cross-sections and optical and kinetic processes in molecular gases. We discuss the application of this control scheme to individual components within a molecular mixture in a selective manner.

arXiv:0907.5300•New Journal of Physics•Oct 30, 2009•117 citations

Motion of spinning molecules in inhomogeneous fields

Johannes Floß, Erez Gershnabel, Ilya Sh. Averbukh

Several laser techniques have been suggested and demonstrated recently for preparing polarizable molecules in rapidly spinning states with a disk-like angular distribution. We consider motion of these spinning disks in inhomogeneous fields and show that the molecular trajectories may be precisely controlled by the tilt of the plane of the laser-induced rotation. The feasibility of the scheme is illustrated by optical deflection of linear molecules twirled by two delayed cross-polarized laser pulses. These results open new ways for many applications involving molecular focusing, guiding, and trapping and may be suitable for separating molecular mixtures by optical and static fields.

arXiv:1010.0887•Physical Review A•Feb 28, 2011•7 citations

Polarization rotation effects in atomic sodium vapor

P. F. Liao, Gary C. Bjorklund

Polarization rotation effects in atomic sodium vapor are studied both experimentally and theoretically. Two pulsed dye laser beams propagate collinearly through a cell containing sodium vapor. The direction of polarization of a linearly polarized dye laser beam of frequency ${\ensuremath{\omega}}_{1}$ is found to be rotated by a circularly polarized beam of frequency ${\ensuremath{\omega}}_{2}$. This rotation is due to the difference in refractive index at ${\ensuremath{\omega}}_{1}$ for right and left circularly polarized light which is produced by the circularly polarized beam. When ${\ensuremath{\omega}}_{1}+{\ensuremath{\omega}}_{2}$ is tuned near the $3S\ensuremath{-}5S$ two-photon transition of atomic sodium, this difference is primarily due to the dispersion associated with the two-photon transition. Other sources of polarization rotation which were identified include (i) real transfers of population to excited atomic levels due to collisionally induced transitions and (ii) optically induced atomic energy-level shifts. The theory includes both the effects of two-photon dispersion and optically induced energy shifts. The application of the two-photon polarization rotation effect as a fast, optically controlled shutter or modulator and as a sensitive detection technique for two-photon spectroscopy are briefly discussed.

Physical Review A•May 1, 1977•59 citations

Coherent control of magneto-optic rotation

Kanhaiya Pandey, Ajay Wasan, Vasant Natarajan A

We experimentally study the rotation of the plane of polarization of a laser beam passing through room-temperature Rb vapour. The rotation occurs because the medium behaves differently for the two orthogonally-polarized components, displaying what is known as circular birefringence or linear dichroism. The difference is induced either by a control laser applied to an auxiliary transition of a ladder-type system, or by an applied axial magnetic field. In the presence of both control laser and magnetic field, the line shape shows an interesting interplay between the two effects with regions of suppressed and enhanced rotation. The line shapes can be understood qualitatively based on a density-matrix analysis of the system.

Journal of Physics B Atomic Molecular and Optical Physics•Nov 10, 2008•32 citations

Nonlinear optical pulse propagation in molecular media

Y. B. Band, Raanan Bavli

We model the response of a molecular medium to an intense pulse of light. We begin by reducing the Maxwell-Bloch equations for a multilevel molecular model system to a set of simplified propagation equations. We thereby obtain expressions for the frequency, temperature, and field intensity dependence of the ground and excited electronic state absorption cross sections, and the emission cross section, as well as the temperature dependence of the decay rate of the excited state. The phenomena of saturation, excited-state absorption, optically induced dichroism and birefringence, vibronic energy transfer, induced molecular alignment, decay of the matter-field interaction energy, and rotational diffusion are considered within the general formalism for describing the propagation of an intense pulse of light in the molecular medium. We find that the cross section for absorption (emission) of a photon is not identical to the cross section for molecular excitation (deexcitation) via the matter-field interaction. This is explained in terms of an energy balance between the matter, radiation, the matter-radiation interaction, and the bath responsible for the broadening of the molecular transitions. The inequality of these cross sections determines whether the system supplies or draws energy from the thermal bath. The rise in the vibrational temperature of molecules subjected to an intense short pulse is shown to significantly affect propagation of the pulse. The alignment of the molecular system resulting from saturation of the ground-state transition by a polarized laser pulse and the effects of the orientational dependence of the matter-field interaction including effects of rotational diffusion are determined. As an example of the formalism we consider pulse propagation in a Rhodamine 6G solution. We fit the parameters of the model to determine the frequency dependence of the ground- and excited-state absorption cross sections and the emission cross section and compare with experimentally determined cross sections. We describe the propagation of a pulse whose temporal width is comparable to the rotational diffusion time of the molecules in the dye solution and calculate polarization pulse probe signals.

Physical Review A•Oct 1, 1987•28 citations

Probing vacuum-induced coherence via magneto-optical rotation in molecular systems

Pardeep Kumar, Bimalendu Deb, Shubhrangshu Dasgupta

We investigate theoretically the effects of vacuum-induced coherence (VIC) on magneto-optical rotation (MOR). We carry out a model study to show that VIC in the presence of a control laser and a magnetic field can lead to large enhancement in the rotation of the plane of polarization of a linearly polarized weak laser with vanishing circular dichroism. This effect can be realized in cold molecular gases and may be used as a sensitive probe for VIC. Such a large MOR angle can also be used to detect weak magnetic field with large measurement sensitivity.

arXiv:1511.02739•Physical Review A•Jun 13, 2016•4 citations
We consider the optical properties of a gas of molecules that are brought to fast unidirectional spinning by a pulsed laser field. It is shown that a circularly polarized probe light passing through the medium inverts its polarization handedness and experiences a frequency shift controllable by the sense and the rate of molecular rotation. Our analysis is supported by two recent experiments on the laser-induced rotational Doppler effect in molecular gases and provides a good qualitative and quantitative description of the experimental observations.
We introduce a new scheme for controlling the sense of molecular rotation. By varying the polarization and the delay between two ultrashort laser pulses, we induce unidirectional molecular rotation, thereby forcing the molecules to rotate clockwise/counterclockwise under field-free conditions. We show that unidirectionally rotating molecules are confined to the plane defined by the two polarization vectors of the pulses, which leads to a permanent anisotropy in the molecular angular distribution. The latter may be useful for controlling collisional cross-sections and optical and kinetic processes in molecular gases. We discuss the application of this control scheme to individual components within a molecular mixture in a selective manner.
Several laser techniques have been suggested and demonstrated recently for preparing polarizable molecules in rapidly spinning states with a disk-like angular distribution. We consider motion of these spinning disks in inhomogeneous fields and show that the molecular trajectories may be precisely controlled by the tilt of the plane of the laser-induced rotation. The feasibility of the scheme is illustrated by optical deflection of linear molecules twirled by two delayed cross-polarized laser pulses. These results open new ways for many applications involving molecular focusing, guiding, and trapping and may be suitable for separating molecular mixtures by optical and static fields.
Polarization rotation effects in atomic sodium vapor are studied both experimentally and theoretically. Two pulsed dye laser beams propagate collinearly through a cell containing sodium vapor. The direction of polarization of a linearly polarized dye laser beam of frequency ${\ensuremath{\omega}}_{1}$ is found to be rotated by a circularly polarized beam of frequency ${\ensuremath{\omega}}_{2}$. This rotation is due to the difference in refractive index at ${\ensuremath{\omega}}_{1}$ for right and left circularly polarized light which is produced by the circularly polarized beam. When ${\ensuremath{\omega}}_{1}+{\ensuremath{\omega}}_{2}$ is tuned near the $3S\ensuremath{-}5S$ two-photon transition of atomic sodium, this difference is primarily due to the dispersion associated with the two-photon transition. Other sources of polarization rotation which were identified include (i) real transfers of population to excited atomic levels due to collisionally induced transitions and (ii) optically induced atomic energy-level shifts. The theory includes both the effects of two-photon dispersion and optically induced energy shifts. The application of the two-photon polarization rotation effect as a fast, optically controlled shutter or modulator and as a sensitive detection technique for two-photon spectroscopy are briefly discussed.
We experimentally study the rotation of the plane of polarization of a laser beam passing through room-temperature Rb vapour. The rotation occurs because the medium behaves differently for the two orthogonally-polarized components, displaying what is known as circular birefringence or linear dichroism. The difference is induced either by a control laser applied to an auxiliary transition of a ladder-type system, or by an applied axial magnetic field. In the presence of both control laser and magnetic field, the line shape shows an interesting interplay between the two effects with regions of suppressed and enhanced rotation. The line shapes can be understood qualitatively based on a density-matrix analysis of the system.
We model the response of a molecular medium to an intense pulse of light. We begin by reducing the Maxwell-Bloch equations for a multilevel molecular model system to a set of simplified propagation equations. We thereby obtain expressions for the frequency, temperature, and field intensity dependence of the ground and excited electronic state absorption cross sections, and the emission cross section, as well as the temperature dependence of the decay rate of the excited state. The phenomena of saturation, excited-state absorption, optically induced dichroism and birefringence, vibronic energy transfer, induced molecular alignment, decay of the matter-field interaction energy, and rotational diffusion are considered within the general formalism for describing the propagation of an intense pulse of light in the molecular medium. We find that the cross section for absorption (emission) of a photon is not identical to the cross section for molecular excitation (deexcitation) via the matter-field interaction. This is explained in terms of an energy balance between the matter, radiation, the matter-radiation interaction, and the bath responsible for the broadening of the molecular transitions. The inequality of these cross sections determines whether the system supplies or draws energy from the thermal bath. The rise in the vibrational temperature of molecules subjected to an intense short pulse is shown to significantly affect propagation of the pulse. The alignment of the molecular system resulting from saturation of the ground-state transition by a polarized laser pulse and the effects of the orientational dependence of the matter-field interaction including effects of rotational diffusion are determined. As an example of the formalism we consider pulse propagation in a Rhodamine 6G solution. We fit the parameters of the model to determine the frequency dependence of the ground- and excited-state absorption cross sections and the emission cross section and compare with experimentally determined cross sections. We describe the propagation of a pulse whose temporal width is comparable to the rotational diffusion time of the molecules in the dye solution and calculate polarization pulse probe signals.
We investigate theoretically the effects of vacuum-induced coherence (VIC) on magneto-optical rotation (MOR). We carry out a model study to show that VIC in the presence of a control laser and a magnetic field can lead to large enhancement in the rotation of the plane of polarization of a linearly polarized weak laser with vanishing circular dichroism. This effect can be realized in cold molecular gases and may be used as a sensitive probe for VIC. Such a large MOR angle can also be used to detect weak magnetic field with large measurement sensitivity.