37 research outputs found
Magneto-Optical Trap for Thulium Atoms
Thulium atoms are trapped in a magneto-optical trap using a strong transition
at 410 nm with a small branching ratio. We trap up to atoms at
a temperature of 0.8(2) mK after deceleration in a 40 cm long Zeeman slower.
Optical leaks from the cooling cycle influence the lifetime of atoms in the MOT
which varies between 0.3 -1.5 s in our experiments. The lower limit for the
leaking rate from the upper cooling level is measured to be 22(6) s. The
repumping laser transferring the atomic population out of the F=3 hyperfine
ground-state sublevel gives a 30% increase for the lifetime and the number of
atoms in the trap.Comment: 4 pages, 6 figure
Coherent Diffusion of Polaritons in Atomic Media
Coherent diffusion pertains to the motion of atomic dipoles experiencing
frequent collisions in vapor while maintaining their coherence. Recent
theoretical and experimental studies on the effect of coherent diffusion on key
Raman processes, namely Raman spectroscopy, slow polariton propagation, and
stored light, are reviewed in this Colloquium.Comment: Submitted to Review of Modern Physic
Magnetometry Based on Nonlinear Magneto-Optical Rotation with Amplitude-Modulated Light
We report on an all-optical magnetometric technique based on nonlinear
magneto-optical rotation with amplitude-modulated light. The method enables
sensitive magnetic-field measurements in a broad dynamic range. We demonstrate
the sensitivity of G/ at 10 mG and the
magnetic field tracking in a range of 40 mG. The fundamental limits of the
method sensitivity and factors determining current performance of the
magnetometer are discussed.Comment: Submitted to Journal of Applied Physics 8 pages, 8 figure
Bcc He as a Coherent Quantum Solid
In this work we investigate implications of the quantum nature of bcc %
He. We show that it is a unique solid phase with both a lattice structure and
an Off-Diagonal Long Range Order of coherently oscillating local electric
dipole moments. These dipoles arise from the local motion of the atoms in the
crystal potential well, and oscillate in synchrony to reduce the dipolar
interaction energy. The dipolar ground-state is therefore found to be a
coherent state with a well defined global phase and a three-component complex
order parameter. The condensation energy of the dipoles in the bcc phase
stabilizes it over the hcp phase at finite temperatures. We further show that
there can be fermionic excitations of this ground-state and predict that they
form an optical-like branch in the (110) direction. A comparison with
'super-solid' models is also discussed.Comment: 12 pages, 8 figure
Buffer-gas induced absorption resonances in Rb vapor
We observe transformation of the electromagnetically induced transparency
(EIT) resonance into the absorption resonance in a interaction
configuration in a cell filled with Rb and a buffer gas. This
transformation occurs as a one-photon detuning of the coupling fields is varied
from the atomic transition. No such absorption resonance is found in the
absence of a buffer gas. The width of the absorption resonance is several times
smaller than the width of the EIT resonance, and the changes of absorption near
these resonances are about the same. Similar absorption resonances are detected
in the Hanle configuration in a buffered cell.Comment: 11 pages, 15 figures; 13 pages, 17 figures, added numerical
simulatio
Enhancement of Magneto-Optic Effects via Large Atomic Coherence
We utilize the generation of large atomic coherence to enhance the resonant
nonlinear magneto-optic effect by several orders of magnitude, thereby
eliminating power broadening and improving the fundamental signal-to-noise
ratio. A proof-of-principle experiment is carried out in a dense vapor of Rb
atoms. Detailed numerical calculations are in good agreement with the
experimental results. Applications such as optical magnetometry or the search
for violations of parity and time reversal symmetry are feasible
Large Faraday rotation of resonant light in a cold atomic cloud
We experimentally studied the Faraday rotation of resonant light in an
optically-thick cloud of laser-cooled rubidium atoms. Measurements yield a
large Verdet constant in the range of 200 000 degrees/T/mm and a maximal
polarization rotation of 150 degrees. A complete analysis of the polarization
state of the transmitted light was necessary to account for the role of the
probe laser's spectrum
Resonant nonlinear magneto-optical effects in atoms
In this article, we review the history, current status, physical mechanisms,
experimental methods, and applications of nonlinear magneto-optical effects in
atomic vapors. We begin by describing the pioneering work of Macaluso and
Corbino over a century ago on linear magneto-optical effects (in which the
properties of the medium do not depend on the light power) in the vicinity of
atomic resonances, and contrast these effects with various nonlinear
magneto-optical phenomena that have been studied both theoretically and
experimentally since the late 1960s. In recent years, the field of nonlinear
magneto-optics has experienced a revival of interest that has led to a number
of developments, including the observation of ultra-narrow (1-Hz)
magneto-optical resonances, applications in sensitive magnetometry, nonlinear
magneto-optical tomography, and the possibility of a search for parity- and
time-reversal-invariance violation in atoms.Comment: 51 pages, 23 figures, to appear in Rev. Mod. Phys. in Oct. 2002,
Figure added, typos corrected, text edited for clarit