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

Quantum Electronics and Laser Science Conference

Deceleration of a thermal beam of Rb

B. Sheehy, S. Hatamian, Richard N. Watts, Harold J. Metcalf

Published Apr 24, 1989• 0 citations
OpenAlex

Abstract

We have used diode laser beams that counter- propagate against a thermal beam of Rb to decelerate the atoms to near-zero velocity and bunch their speeds into a very narrow range. As the atoms decelerate, their changing Doppler shift is compensated by increasing the laser frequency. This chirping is easily accomplished with diode lasers because of their strong frequency dependence on current.

Related papers

Diode-laser deceleration and collimation of a rubidium beam

B. Sheehy, S-Q. Shang, Richard N. Watts +2 more

We report the use of frequency-chirped diode lasers to decelerate a thermal atomic beam of Rb and, in a separate experiment, the use of frequency-stabilized diode lasers to collimate the beam with optical molasses. For this we used a 100-mW cw laser-diode array injection locked to light from a low-power, frequency-narrowed, single-stripe diode laser. Also, a novel scheme for imaging the neutral-atom beam profile has been developed for monitoring the collimation experiments in two dimensions. We have increased both beam brightness and intensity by a factor of more than 20.

Journal of the Optical Society of America B•Nov 1, 1989•51 citations

Laser Deceleration of an Atomic Beam

William D. Phillips, Harold J. Metcalf

Deceleration and velocity bunching of Na atoms in an atomic beam have been observed. The deceleration, caused by absorption of counterpropagating resonant laser light, amounts to 40% of the initial thermal velocity, corresponding to about 15 000 absorptions. Atoms were kept in resonance with the laser by using a spatially varying magnetic field to provide a changing Zeeman shift to compensate for the changing Doppler shift as the atoms decelerated.

Physical Review Letters•Mar 1, 1982•590 citations

Cooling cesium atoms using diode lasers

Carl Wieman, R. N. Watts

We have cooled and stopped a beam of cesium atoms using frequency chirped diode lasers. In this technique, a moving atom absorbs and reemits many photons from a counter propagating laser that is frequency swept to keep it in resonance with an atomic transition. The resulting momentum transfer slows the atom. The basic approach is identical to that developed by Hall and co-workers, however, the use of diode lasers allows us to obtain the necessary frequency modulation simply by sweeping the laser injection current. We use two diode lasers tuned to each of the 6s hyperfine ground state levels to drive the 6s—6p3/2 transitions. Each laser is simultaneously swept over the Doppler profile of the 100°C thermal cesium beam to bring a substantial number to a stop. Using additional fast frequency modulation, the same lasers are used to probe the resulting velocity distribution. This technique allows us to bring ~106 atoms/cm3 to a temperature of 1 K. This method is an extremely simple and inexpensive way to produce cold atoms.

International Laser Science Conference•Jan 1, 1986•0 citations

A laser diode system and its use in a laser cooling experiment

C. C. Bradley

A system to control and stabilize the output of visible laser diodes was developed and used to measure the velocity distribution of lithium atoms in a laser cooling experiment. Circuitry was designed and built for controlling the diode temperature and current, and optical feedback from a grating was used to further tune the laser and to narrow its lineshape. In the experiment, atoms from a thermal lithium beam were slowed to near zero velocity using a multi-frequency relay chirp technique.

•Jan 1, 1992•0 citations

Laser cooling and trapping of rubidium

Christopher D. Wallace, Timothy T. Grove, T. Dinneen +2 more

We have laser cooled an atomic beam of rubidium with diode lasers and have used these slow atoms to load a magneto-optical trap. The cooling is performed with the frequency-chirp method,1,2 in which the laser's frequency is ramped linearly (by the injection currant) to maintain resonance with the decelerating atoms. Two synchronously chirped lasers are required to prevent optical hyperfine pumping of the ground state. The chirp typically covers 500 MHz in 10 ms. At the end of each ramp, the resulting velocity distribution is measured with a pulsed probe laser. By varying the end point of the chirp, we are able to obtain slow atoms with average velocities ranging from 200 to −50 m/s. The widths of the velocity distributions are measured to be approximately 40 m/s. This relatively large width results from the inherent linewidth (~30 MHz) of the free-running diode lasers used for both cooling and probing.

Quantum Electronics and Laser Science Conference•May 12, 1991•0 citations

Trapping and cooling of atoms

C. J. Pethick, H. Smith

The advent of the laser opened the way to the development of powerful methods for producing and manipulating cold atomic gases. To set the stage we describe a typical experiment, which is shown schematically in Fig. 4.1. A beam of sodium atoms emerges from an oven at a temperature of about 600 K, corresponding to a speed of about 800 m s −1 , and is then passed through a so-called Zeeman slower, in which the velocity of the atoms is reduced to about 30 m s −1 , corresponding to a temperature of about 1 K. In the Zeeman slower, a laser beam propagates in the direction opposite that of the atomic beam, and the radiation force produced by absorption of photons retards the atoms. Due to the Doppler effect, the frequency of the atomic transition in the laboratory frame is not generally constant, since the atomic velocity varies. However, by applying an inhomogeneous magnetic field designed so that the Doppler and Zeeman effects cancel, the frequency of the transition in the rest frame of the atom may be held fixed. On emerging from the Zeeman slower the atoms are slow enough to be captured by a magneto-optical trap (MOT), where they are further cooled by interactions with laser light to temperatures of order 100 μK. Another way of compensating for the changing Doppler shift is to increase the laser frequency in time, which is referred to as ‘chirping’.

Cambridge University Press eBooks•Sep 11, 2008•0 citations
We have used diode laser beams that counter- propagate against a thermal beam of Rb to decelerate the atoms to near-zero velocity and bunch their speeds into a very narrow range. As the atoms decelerate, their changing Doppler shift is compensated by increasing the laser frequency. This chirping is easily accomplished with diode lasers because of their strong frequency dependence on current.
We report the use of frequency-chirped diode lasers to decelerate a thermal atomic beam of Rb and, in a separate experiment, the use of frequency-stabilized diode lasers to collimate the beam with optical molasses. For this we used a 100-mW cw laser-diode array injection locked to light from a low-power, frequency-narrowed, single-stripe diode laser. Also, a novel scheme for imaging the neutral-atom beam profile has been developed for monitoring the collimation experiments in two dimensions. We have increased both beam brightness and intensity by a factor of more than 20.
We have cooled and stopped a beam of cesium atoms using frequency chirped diode lasers. In this technique, a moving atom absorbs and reemits many photons from a counter propagating laser that is frequency swept to keep it in resonance with an atomic transition. The resulting momentum transfer slows the atom. The basic approach is identical to that developed by Hall and co-workers, however, the use of diode lasers allows us to obtain the necessary frequency modulation simply by sweeping the laser injection current. We use two diode lasers tuned to each of the 6s hyperfine ground state levels to drive the 6s—6p3/2 transitions. Each laser is simultaneously swept over the Doppler profile of the 100°C thermal cesium beam to bring a substantial number to a stop. Using additional fast frequency modulation, the same lasers are used to probe the resulting velocity distribution. This technique allows us to bring ~106 atoms/cm3 to a temperature of 1 K. This method is an extremely simple and inexpensive way to produce cold atoms.
We have laser cooled an atomic beam of rubidium with diode lasers and have used these slow atoms to load a magneto-optical trap. The cooling is performed with the frequency-chirp method,1,2 in which the laser's frequency is ramped linearly (by the injection currant) to maintain resonance with the decelerating atoms. Two synchronously chirped lasers are required to prevent optical hyperfine pumping of the ground state. The chirp typically covers 500 MHz in 10 ms. At the end of each ramp, the resulting velocity distribution is measured with a pulsed probe laser. By varying the end point of the chirp, we are able to obtain slow atoms with average velocities ranging from 200 to −50 m/s. The widths of the velocity distributions are measured to be approximately 40 m/s. This relatively large width results from the inherent linewidth (~30 MHz) of the free-running diode lasers used for both cooling and probing.
The advent of the laser opened the way to the development of powerful methods for producing and manipulating cold atomic gases. To set the stage we describe a typical experiment, which is shown schematically in Fig. 4.1. A beam of sodium atoms emerges from an oven at a temperature of about 600 K, corresponding to a speed of about 800 m s −1 , and is then passed through a so-called Zeeman slower, in which the velocity of the atoms is reduced to about 30 m s −1 , corresponding to a temperature of about 1 K. In the Zeeman slower, a laser beam propagates in the direction opposite that of the atomic beam, and the radiation force produced by absorption of photons retards the atoms. Due to the Doppler effect, the frequency of the atomic transition in the laboratory frame is not generally constant, since the atomic velocity varies. However, by applying an inhomogeneous magnetic field designed so that the Doppler and Zeeman effects cancel, the frequency of the transition in the rest frame of the atom may be held fixed. On emerging from the Zeeman slower the atoms are slow enough to be captured by a magneto-optical trap (MOT), where they are further cooled by interactions with laser light to temperatures of order 100 μK. Another way of compensating for the changing Doppler shift is to increase the laser frequency in time, which is referred to as ‘chirping’.