81 research outputs found
Magnetic field--induced modification of selection rules for Rb D line monitored by selective reflection from a vapor nanocell
Magnetic field-induced giant modification of the probabilities of five
transitions of of Rb and
three transitions of of Rb
forbidden by selection rules for zero magnetic field has been observed
experimentally and described theoretically for the first time. For the case of
excitation with circularly-polarized () laser radiation, the
probability of transition becomes
the largest among the seventeen transitions of Rb group, and the probability of transition becomes the largest among the nine transitions of
Rb group, in a wide range of magnetic
field 200 -- 1000 G. Complete frequency separation of individual Zeeman
components was obtained by implementation of derivative selective reflection
technique with a 300 nm-thick nanocell filled with Rb, allowing formation of
narrow optical resonances. Possible applications are addressed. The theoretical
model is perfectly consistent with the experimental results.Comment: 6 pages, 5 figure
Observation of magnetically-induced transition intensity redistribution in the onset of the hyperfine Paschen-Back regime
The Zeeman effect is an important topic in atomic spectroscopy. The induced
change in transition frequencies and amplitudes finds applications in the
Earth-field-range magnetometry. At intermediate magnetic field amplitude , where is the magnetic dipole constant
of the ground state, and is the Bohr magneton ( kG for
Cs), the rigorous rule is affected by the coupling between
magnetic sub-levels induced by the field. Transitions satisfying , referred to as magnetically-induced transitions, can be observed. Here,
we show that a significant redistribution of the Cs magnetically-induced transition intensities occurs with
increasing magnetic field. We observe that the strongest transition in the
group ( polarization) for cease to
be the strongest for . On the other hand, the strongest transition in
the group ( polarization) remains so for all
our measurements with magnetic fields up to 9 kG. These results are in
agreement with a theoretical model. The model predicts that similar
observations can be made for all alkali metals, including Na, K and Rb atoms.
Our findings are important for magnetometers utilizing the Zeeman effect above
Earth field, following the rapid development of micro-machined vapor-cell-based
sensors
Sub-Doppler spectroscopy of the near-UV Cs atom 6S-7P transition in a microfabricated vapor cell
We report on the characterization of sub-Doppler resonances detected by
probing the 6S-7P transition of Cs atom at 459 nm in a
microfabricated vapor cell. The dependence of the sub-Doppler resonance
(linewidth, amplitude) on some key experimental parameters, including the laser
intensity and the cell temperature, is investigated. These narrow atomic
resonances are of interest for high-resolution spectroscopy, instrumentation,
and may constitute the basis of a near-UV microcell optical standard
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Restraint, disinhibition and food-related processing bias
This study examined associations between restraint, disinhibition and food-related processing bias (FPB, assessed by the emotional Stroop task) in males and females in the UK, Greece and Iran. Results showed high restraint was associated with higher FPB. However, high restrained current dieters showed lower FPB that high restrained non-dieters. There was no significant difference in FPB for those showing high versus low disinhibition. Results are discussed in relation to theories of incentive salience and current concerns
Remote Detection Optical Magnetometry
Sensitive magnetometers have been applied in a wide range of research fields,
including geophysical exploration, bio-magnetic field detection, ultralow-field
nuclear magnetic resonance, etc. Commonly, magnetometers are directly placed at
the position where the magnetic field is to be measured. However, in some
situations, for example in near space or harsh environments, near nuclear
reactors or particle accelerators, it is hard to place a magnetometer directly
there. If the magnetic field can be detected remotely, i.e., via stand-off
detection, this problem can be solved. As optical magnetometers are based on
optical readout, they are naturally promising for stand-off detection. We
review various approaches to optical stand-off magnetometry proposed and
developed over the years, culminating in recent results on measuring magnetic
fields in the mesosphere using laser guide stars, magnetometry with
mirrorless-lasing readout, and proposals for satellite-assisted interrogation
of atmospheric sodium.Comment: 68 pages, 19 figure
Mirrorless lasing: a theoretical perspective
Mirrorless lasing has been a topic of particular interest for about a decade
due to promising new horizons for quantum science and applications. In this
work, we review first-principles theory that describes this phenomenon, and
discuss degenerate mirrorless lasing in a vapor of Rb atoms, the mechanisms of
amplification of light generated in the medium with population inversion
between magnetic sublevels within the line, and challenges associated
with experimental realization
Universal determination of comagnetometer response to spin couplings
We propose and demonstrate a general method to calibrate the
frequency-dependent response of self-compensating noble-gas-alkali-metal
comagnetometers to arbitrary spin perturbations. This includes magnetic and
nonmagnetic perturbations like rotations and exotic spin interactions. The
method is based on a fit of the magnetic field response to an analytical model.
The frequency-dependent response of the comagnetometer to arbitrary spin
perturbations can be inferred using the fit parameters. We demonstrate the
effectiveness of this method by comparing the inferred rotation response to an
experimental measurement of the rotation response. Our results show that
experiments relying on zero-frequency calibration of the comagnetometer
response can over- or under-estimate the comagnetometer sensitivity by orders
of magnitude over a wide frequency range. Moreover, this discrepancy
accumulates over time as operational parameters tend to drift during
comagnetometer operation. The demonstrated calibration protocol enables
accurate prediction and control of comagnetometer sensitivity to, for example,
ultralight bosonic dark-matter fields coupling to electron or nuclear spins as
well as accurate monitoring and control of the relevant system parameters
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