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:physics/0305124

Excitation Of A Funnel-Shape Optical Near Field By The Laguarre-Gaussian Doughnut Beam

S. M. Iftiquar, Haruhiko Ito, Akifumi Takamizawa, Motoichi Ohtsu

Published May 29, 2003• 0 citations
arXivHTMLPDF

Abstract

Optical near field has been generated by Laguarre-Gaussian doughnut beam on inner surface of "atom funnel". The resulting optical near field has been measured with the help of fiber probe and a consequent effect on cold atoms- released from MOT, has been estimated. Atoms with temperature less than 10 micro_kelvin can be reflected by the optical near field.

DOI
10.48550/arxiv.physics/0305124

Related papers

Mode conversion in optical beam in order to create funnel shaped optical near field to collect cold Rb atoms from MOT

S. M. Iftiquar

Doughnut shaped light beam has been generated from Gaussian mode ($TEM_{00}$) cw-Ti sapphire laser. After splitting the pump beam into two equal intensity components and introducing unequal convergence and phase delay while they are recombined it results in doughnut mode. Such a beam is tunable and have long propagation length. The evanescent field generated by 360 mW (at 780 nm wavelength) of such a beam creates optical field of 600 nm decay length with a 5.75 neV repulsive dipole potential. Thus cold Rb atoms (at 10{$μ$}K or less temperature) released from MOT can be reflected by the surface so that the atoms are collected ultimately at the bottom of the prism. By focussing such doughnut beam with 8 cm focal length converging lens, the dark radius reduces to 22{$μ$}. We also observe such beam to contain azimuthal phase as well as radial phase distribution.

arXiv:physics/0306021•Jun 3, 2003•0 citations

Tunable doughnut light beam for a near-field optical funnel of atoms

S. M. Iftiquar, Hajime Ito, Motoichi Ohtsu

A doughnut-shaped Laguerre-Gaussian (LG) beam has been generated through interference of two spherical waves. The beam has a 5 mm bright ring and a 250-microns dark center suitable for our atom funnel experiment. The power conversion efficiency from a Gaussian mode to the LG mode is about 50%.

Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR)•Nov 13, 2002•2 citations

A tunable doughnut laser beam for cold-atom experiments

S. M. Iftiquar

A doughnut-shaped light beam has been generated from a Gaussian mode (TEM 00 ). Upon splitting the pump beam into two equal-intensity components and introducing unequal convergences with a phase delay while they are recombined, a doughnut mode results. The output beam is tunable and has a long propagation length. The evanescent field generated by a 360 mW (at 780 nm wavelength) beam creates an optical field of 600 nm decay length with a 5.75 neV repulsive dipole potential. Thus cold Rb atoms (at a temperature of 10 μK or less) released from a magneto-optical trap can be reflected by the funnel surface, with the result that the atoms are ultimately collected at the bottom.

Journal of Optics B Quantum and Semiclassical Optics•Dec 9, 2002•8 citations

Atomic funnel with evanescent light

Hajime Ito, K. Sakaki, Wonho Jhe +1 more

We propose an atomic funnel composed of an evanescent-light mirror produced in a conical hollow prism. The funneling of cold Rb atoms released from a magneto-optical trap is simulated in the scheme of the evanescent-light-induced Sisyphus cooling for compensating the heating by gravity. A geometric method of the conversion of a Gaussian light beam into a doughnut-shaped light beam suitable for the atomic funnel is also experimentally demonstrated by means of a double-cone prism. Under the assumption of a proper optical intensity distribution over the inner surface of a specific conical hollow prism, the Monte Carlo simulation including the van der Waals interaction shows that a half of the released Rb atoms can be collected and the mean temperature of the collected atoms is low enough for the application to be guided with a bent hollow optical fiber.

Physical Review A•Jul 1, 1997•77 citations

Atom guiding and cooling by a dark hollow laser beam

Kwanil Lee, Xinye Xu, Seunghyup Yoo +2 more

Atom guiding in an atomic funnel is very useful for many interesting atom optical experiments requiring the precise control of atomic motion. We have obtained a doughnut-shaped laser beam by coupling a Ti:sapphire laser into a hollow core optical fiber and collimating the output laser beam of the fiber with a microscope objective lens. Using such a doughnut-shaped laser beam [2 mm inner diameter and a 5 mm outer diameter at the trapping position (about 1m away from the objective lens)l, we have guided the trapped cold Rb atoms in the atomic funnel.

Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR)•Jan 20, 2003•1 citation

Multireflection of Cold Atoms in a Near-Field Optical Funnel

Akifumi Takamizawa, Haruhiko Ito, Motoichi Ohtsu

Multireflection of cold Rb atoms occurs inside a reversed triangular hollow prism with a blue-detuned optical near field. We examine it with a probe light beam, using the frequency detuning and the diameter of an excitation light beam as parameters. In the first bounce, the number density of the reflected atoms reaches a maximum of 10 6 atom/cm 3 at a blue detuning of 0.7 GHz when the beam diameter is 4 mm. The Rb atoms repeat reflection with a period of about 15 ms and an efficiency of 83% per bounce. A cold Rb atomic beam with a high flux of 4 × 10 11 atom/(cm 2 ·s) can be generated through a near-field optical funnel composed of the prism.

Japanese Journal of Applied Physics•Oct 15, 2002•10 citations
Optical near field has been generated by Laguarre-Gaussian doughnut beam on inner surface of "atom funnel". The resulting optical near field has been measured with the help of fiber probe and a consequent effect on cold atoms- released from MOT, has been estimated. Atoms with temperature less than 10 micro_kelvin can be reflected by the optical near field.
Doughnut shaped light beam has been generated from Gaussian mode (TEM00TEM_{00}TEM00​) cw-Ti sapphire laser. After splitting the pump beam into two equal intensity components and introducing unequal convergence and phase delay while they are recombined it results in doughnut mode. Such a beam is tunable and have long propagation length. The evanescent field generated by 360 mW (at 780 nm wavelength) of such a beam creates optical field of 600 nm decay length with a 5.75 neV repulsive dipole potential. Thus cold Rb atoms (at 10{μμμ}K or less temperature) released from MOT can be reflected by the surface so that the atoms are collected ultimately at the bottom of the prism. By focussing such doughnut beam with 8 cm focal length converging lens, the dark radius reduces to 22{μμμ}. We also observe such beam to contain azimuthal phase as well as radial phase distribution.
A doughnut-shaped light beam has been generated from a Gaussian mode (TEM 00 ). Upon splitting the pump beam into two equal-intensity components and introducing unequal convergences with a phase delay while they are recombined, a doughnut mode results. The output beam is tunable and has a long propagation length. The evanescent field generated by a 360 mW (at 780 nm wavelength) beam creates an optical field of 600 nm decay length with a 5.75 neV repulsive dipole potential. Thus cold Rb atoms (at a temperature of 10 μK or less) released from a magneto-optical trap can be reflected by the funnel surface, with the result that the atoms are ultimately collected at the bottom.
We propose an atomic funnel composed of an evanescent-light mirror produced in a conical hollow prism. The funneling of cold Rb atoms released from a magneto-optical trap is simulated in the scheme of the evanescent-light-induced Sisyphus cooling for compensating the heating by gravity. A geometric method of the conversion of a Gaussian light beam into a doughnut-shaped light beam suitable for the atomic funnel is also experimentally demonstrated by means of a double-cone prism. Under the assumption of a proper optical intensity distribution over the inner surface of a specific conical hollow prism, the Monte Carlo simulation including the van der Waals interaction shows that a half of the released Rb atoms can be collected and the mean temperature of the collected atoms is low enough for the application to be guided with a bent hollow optical fiber.
Atom guiding in an atomic funnel is very useful for many interesting atom optical experiments requiring the precise control of atomic motion. We have obtained a doughnut-shaped laser beam by coupling a Ti:sapphire laser into a hollow core optical fiber and collimating the output laser beam of the fiber with a microscope objective lens. Using such a doughnut-shaped laser beam [2 mm inner diameter and a 5 mm outer diameter at the trapping position (about 1m away from the objective lens)l, we have guided the trapped cold Rb atoms in the atomic funnel.
Multireflection of cold Rb atoms occurs inside a reversed triangular hollow prism with a blue-detuned optical near field. We examine it with a probe light beam, using the frequency detuning and the diameter of an excitation light beam as parameters. In the first bounce, the number density of the reflected atoms reaches a maximum of 10 6 atom/cm 3 at a blue detuning of 0.7 GHz when the beam diameter is 4 mm. The Rb atoms repeat reflection with a period of about 15 ms and an efficiency of 83% per bounce. A cold Rb atomic beam with a high flux of 4 × 10 11 atom/(cm 2 ·s) can be generated through a near-field optical funnel composed of the prism.