© 2026 Aqora Quantum S.A.S.

Terms Privacy Legal Notice

Physical Review A

Theory of light-induced drift and the optical piston

Gerard Nienhuis

Published Mar 1, 1985• 42 citations

Abstract

Light-induced drift arises when optically excited atoms with a Doppler-selected velocity suffer a diffusive friction that is different from that of ground-state atoms. When the atoms form an optically dense system, this drift can cause a piston effect, which sweeps the atoms in the propagation direction of the field. We derive coupled differential equations for the density of atoms and the light intensity, with an explicit expression for the drift velocity in terms of easily accessible parameters. Solutions of these equations are obtained for the stationary state in a closed cell. The density at the dark end of the cell, considered as the response to the incident-light intensity as its driving force, exhibits a discontinuity resembling a second-order phase transition for an optically dense system. We also obtain solutions with a soliton character, describing a localized density packet moving at uniform speed.

DOI: 10.1103/physreva.31.1636

Related papers

Theory of high-field effects in light-induced drift

Faris Gel’mukhanov, Jos E. M. Haverkort, S. W. M. Borst +1 more

We address theoretically the effects of a large laser intensity on the phenomenon of light-induced drift. The velocity selectivity of the atom-field interaction decreases due to saturation broadening and this leads to a maximum of the drift velocity as a function of the laser intensity. Analytical expressions for the drift velocity are derived in the case of two-level atoms, assuming a strong collision model. Consequences of this high-field effect are discussed for various manifestations of light-induced drift such as propagation of a soliton in an infinitely long cell, described by the Burgers equation, and collisions of such solitons. The analogy with hydrodynamic shock waves, described by the same Burgers equation, is fruitfully explored. We also address high-field effects on the density distribution produced by light-induced drift in a finite cell. In all these manifestations of light-induced drift the cases of high field and low field show qualitatively different behaviors which are of a complementary nature.

Physical Review A•Jul 1, 1987•18 citations

Magneto-optic drift of ions

Rupamanjari Ghosh, Sushanta Dattagupta, J. Singh

Light-induced drift of optically active atoms in a buffer gas is a consequence of the unequal diffusive frictions suffered by the excited and the ground-state atoms. This drift can be used to create an ``optical piston,'' in which the active atoms are pushed forward by light through the semipermeable membrane of the buffer gas. Normally, optical piston effect is studied when the active atoms are neutral in a confined one-dimensional situation. We present a detailed theory of this phenomenon when the active atoms are charged and a magnetic field is applied for ``tuning'' the direction as well as the magnitude of the drift, thus removing the necessity of confinement. Our study is in different geometries of the light beam and the magnetic field, first in the weak collision model, and then for the strong collision and the Boltzmann-Lorentz models.

Physical Review A•Nov 14, 2001•0 citations

Magneto-Optic Piston Effect

Sushanta Dattagupta, Rupamanjari Ghosh, Jagmeet Singh

Light-induced drift of optically active atoms in a buffer gas is a consequence of the unequal diffusive frictions suffered by the excited and the ground-state atoms. This drift can be used to create an ``optical piston,'' which is best observed when the piston action is confined to a one-dimensional motion. We show that a novel way of realizing this phenomenon is to apply a magnetic field on charged active atoms.

Physical Review Letters•Jul 26, 1999•5 citations

General diffusion equation for light-induced drift

Gerard Nienhuis, Stanisław Kryszewski

We derive a general diffusion equation for the density of an atomic vapor immersed in a buffer gas and irradiated by nearly resonant light. The combination of velocity-selective excitation with state-dependent rates of velocity-changing collisions then gives rise to a drift term, and at the same time the diffusion tensor becomes anisotropic and intensity dependent. Both the effect of light-induced drift and diffusive pulling of atoms by the light are described by this diffusion equation in a consistent and correlated fashion.

Physical Review A•Aug 1, 1987•18 citations

The optical piston in a capillary cell with open ends

H. G. C. Werij, Gerard Nienhuis, J. P. Woerdman

The authors present measurements of the time evolution of the spatial density distribution of Na atoms in an argon buffer gas, inside a capillary cell with open ends. The entrance of the capillary is irradiated with a laser beam that fills its cross section, so that light-induced drift occurs. For sufficiently high intensity, a steep front may build up, which in some cases runs backwards, against the propagation direction of the light, and against the drift velocity. This happens in particular when the initial optical thickness is just above unity. The authors also study the analytical and numerical solution of the macroscopic equations for the optical piston. The steady-state distribution is found to display a sharp variation when the initial optical thickness passes the value unity. They find satisfactory agreement with the measurements.

Journal of Physics B Atomic Molecular and Optical Physics•Sep 28, 1988•2 citations

Optical Hall effect

Jagmeet Singh, Rupamanjari Ghosh, Sushanta Dattagupta

Drift of optically active atoms in a buffer gas induced by an incident light field is a consequence of the unequal diffusive frictions suffered by the excited and the ground-state atoms. We investigate this light-induced drift in the presence of a magnetic field in a direction perpendicular to the incident light, which gives rise to an interesting effect, appropriately called the ``optical Hall effect.''

Physical Review A•Jan 13, 2000•6 citations

Light-induced drift arises when optically excited atoms with a Doppler-selected velocity suffer a diffusive friction that is different from that of ground-state atoms. When the atoms form an optically dense system, this drift can cause a piston effect, which sweeps the atoms in the propagation direction of the field. We derive coupled differential equations for the density of atoms and the light intensity, with an explicit expression for the drift velocity in terms of easily accessible parameters. Solutions of these equations are obtained for the stationary state in a closed cell. The density at the dark end of the cell, considered as the response to the incident-light intensity as its driving force, exhibits a discontinuity resembling a second-order phase transition for an optically dense system. We also obtain solutions with a soliton character, describing a localized density packet moving at uniform speed.

We address theoretically the effects of a large laser intensity on the phenomenon of light-induced drift. The velocity selectivity of the atom-field interaction decreases due to saturation broadening and this leads to a maximum of the drift velocity as a function of the laser intensity. Analytical expressions for the drift velocity are derived in the case of two-level atoms, assuming a strong collision model. Consequences of this high-field effect are discussed for various manifestations of light-induced drift such as propagation of a soliton in an infinitely long cell, described by the Burgers equation, and collisions of such solitons. The analogy with hydrodynamic shock waves, described by the same Burgers equation, is fruitfully explored. We also address high-field effects on the density distribution produced by light-induced drift in a finite cell. In all these manifestations of light-induced drift the cases of high field and low field show qualitatively different behaviors which are of a complementary nature.

Light-induced drift of optically active atoms in a buffer gas is a consequence of the unequal diffusive frictions suffered by the excited and the ground-state atoms. This drift can be used to create an ``optical piston,'' in which the active atoms are pushed forward by light through the semipermeable membrane of the buffer gas. Normally, optical piston effect is studied when the active atoms are neutral in a confined one-dimensional situation. We present a detailed theory of this phenomenon when the active atoms are charged and a magnetic field is applied for ``tuning'' the direction as well as the magnitude of the drift, thus removing the necessity of confinement. Our study is in different geometries of the light beam and the magnetic field, first in the weak collision model, and then for the strong collision and the Boltzmann-Lorentz models.

We derive a general diffusion equation for the density of an atomic vapor immersed in a buffer gas and irradiated by nearly resonant light. The combination of velocity-selective excitation with state-dependent rates of velocity-changing collisions then gives rise to a drift term, and at the same time the diffusion tensor becomes anisotropic and intensity dependent. Both the effect of light-induced drift and diffusive pulling of atoms by the light are described by this diffusion equation in a consistent and correlated fashion.

The authors present measurements of the time evolution of the spatial density distribution of Na atoms in an argon buffer gas, inside a capillary cell with open ends. The entrance of the capillary is irradiated with a laser beam that fills its cross section, so that light-induced drift occurs. For sufficiently high intensity, a steep front may build up, which in some cases runs backwards, against the propagation direction of the light, and against the drift velocity. This happens in particular when the initial optical thickness is just above unity. The authors also study the analytical and numerical solution of the macroscopic equations for the optical piston. The steady-state distribution is found to display a sharp variation when the initial optical thickness passes the value unity. They find satisfactory agreement with the measurements.