Physical Review A

Process of stopping atoms with the Zeeman tuning technique with a single laser

Marcel Eduardo Firmino, C. A. Faria Leite, Sérgio Carlos Zílio, Vanderlei Salvador Bagnato

Published Apr 1, 1990• 15 citations

Abstract

We report an observation of atoms stopped by laser light in an experiment using the Zeeman tuning technique. In contrast to previous experiments using the same technique, we are able to stop the atoms outside the slower solenoid using a single laser. The deceleration process is monitored through the measurement of the fluorescence along the deceleration path in such a way that the slower laser is also used for diagnosis. This technique also permits the realization of a few interesting observations on the process such as the position where the atoms stop scattering photons.

DOI: 10.1103/physreva.41.4070

Related papers

The Effect of a Fluctuating Laser Field on the Process of Decelerating Atoms in the Zeeman Tuning Technique

Reginaldo de Jesus Napolitano, Vanderlei Salvador Bagnato

We present a study on the process of atomic deceleration in the Zeeman tuning technique when a fluctuating laser is used. The characterization of the deceleration is made through the analysis of velocity trajectories (k v(z)) from integration of the averaged equation of motion obtained from the Bloch optical equations. Atomic motion described from an accelerated frame of reference aids the analysis of the process. It is shown that the capability of an atom to follow a magnetic field profile is more sensitive to amplitude than to phase fluctuations. The analysis presented here permits evaluation of laser quality beam on optical deceleration of atoms.

Journal of Modern OpticsFeb 1, 19932 citations

Diagnostic technique for Zeeman-compensated atomic beam slowing: Technique and results

Peter Molenaar, P. van der Straten, H G M Heideman +1 more

We have developed a diagnostic tool for the study of Zeeman-compensated slowing of an alkali-metal atomic beam. Our time-of-flight technique measures the longitudinal velocity distribution of the slowed atoms with a resolution below the Doppler limit. Furthermore, it can map the position and velocity distribution of atoms in either ground hyperfine level inside the solenoid without any devices inside the solenoid. The technique reveals the optical pumping effects and shows in detail how the slowing within the solenoid proceeds. We find for Na that most atoms in the chosen hyperfine state are decelerated in the slowing process. The width of the velocity distribution is determined mainly by inhomogeneities in the slowing laser beam. Using the central most uniform part of an expanded laser beam, the width is reduced to 2.5 m/s, corresponding to 3.2 mK. Finally, we discuss and show a method to produce a beam with two-velocity components for the study of head-tail low-energy collisions.

Physical Review AJan 1, 199742 citations

Adiabatric following and optical pumping effects in the process of slowing atoms with the Zeeman tuning technique

Vanderlei Salvador Bagnato, Valdir Colussi, Euclydes Marega Jr. +2 more

Through studying the declaration process of an atomic beam of sodium using the Zeeman tuning technique1 we verify that for certain laser detunings the atoms do not follow the magnetic field adiabatically. The explanation for this is that at some point the deceleration required is above the maximum allowed value2 of (ħKΓ)/(2M), where K is the laser wave vector, Γ is the natural transition linewidth, and M is the atomic mass.

May 21, 19900 citations

Deceleration of atoms with a fluctuating laser field

Reginaldo de Jesus Napolitano, Vanderlei Salvador Bagnato

In a recent publication1 we have analyzed the stability of the deceleration process of atoms in the Zeeman tuning technique2 by looking at the velocity profile of the atoms along the magnetic field. When the velocity [v(z)] follows the field profile [B(z)] we refer to this as adiabatic following of atoms because the absorption is adiabatically adjusted to each position so that v(z) follows B(z). This situation does not hold everywhere; in fact, at points where the absorption cannot be adiabatically adjusted the velocity ceases to follow the field interrupting the deceleration. The existence of fluctuations on the laser field produces dramatic changes on the expected behavior of the atoms during the deceleration. We have made numerical simulation and analytical investigation where v(z) is obtained for cases where the laser field has frequency and amplitude fluctuations produced by Markovian and Gaussian stochastic processes. In both cases, the deceleration is dependent on the spectral densities of the fluctuations. The process seems to be more sensitive to amplitude than to frequency fluctuation. These results are important in determining the desired characteristics of the laser source on atoms deceleration experiments.

Annual Meeting Optical Society of AmericaJan 1, 19910 citations

Laser Cooling of a Helium Atomic Beam

Norio Morita, M. Kumakura

The laser cooling of a helium atomic beam in the 2s3S1 metastable state has been demonstrated. Using a single-mode LNA (La1-x Nd x MgAl11O19) laser resonant with the 2s3S1-2p3P2 transition, the metastable atoms are cooled by the Doppler cooling method combined with the Zeeman-tuning technique. To monitor the velocity distribution, the Doppler profile of the 2p3P2-3d3D3 transition is observed. As a result, the most probable velocity of the metastable helium atoms, which is initially 750 m/s, is decelerated to 90 m/s.

Japanese Journal of Applied PhysicsSep 1, 19918 citations

A Zeeman slower for molecules

Kaebert, Paul

Cold molecules are an invaluable tool for modern physics. Cold atoms have already revolutionized precision metrology, allowed for spectacular findings in quantum physics and opened the door for the creation and observation of novel states of matter. Cold molecules bring with them additional degrees of freedom which give rise to unique properties that enable new kinds of experiments. For these experiments it is of vital importance to start with a sufficiently large number of cold molecules. There are multiple paths for the slowing and cooling of atoms and most of the slowing techniques utilizing lasers for direct cooling have been transferred to the molecular case with its specific requirements. The Zeeman slowing technique is advantageous for loading a trap with cold particles but had not yet been transferred from atoms to the molecular case. In this thesis I will show the first realization of the Zeeman slowing technique for diatomic molecules. This thesis will discuss several preparatory steps: Our group has had some ideas to collimate the molecular beam with a conical nozzle outlet at the buffer gas cell which I investigated on potassium atoms generated by the ablation of 39K35Cl inside the buffer gas cell. I also realized a fluorescence spectroscopy of the |XΣ1/2, N = 1, v = 0⟩ → |AΠ1/2, N = 0, v = 0⟩ transition in magnetic fields up to 300 G and confirmed simulations regarding our two laser cycling scheme in the Paschen-Back regime by measuring the scattering rate of light on one molecule. Finally, I created pre-cooled 40Ca19F with a forward velocity of around 150 m s−1 from a 40Ca19F2 target with laser ablation inside a cryogenic buffer gas cell. With the Zeeman slowing technique I slowed the molecules down to 25 m s−1, a velocity where trapping can be possible. I have also shown the characteristic compression into specific velocity classes for not yet trappable velocities. Together these two findings demonstrate that molecular Zeeman slowing is possible and a real promising tool for future experiments.

Jan 1, 20250 citations