431 research outputs found
Hanle effect in coherent backscattering
We study the shape of the coherent backscattering (CBS) cone obtained when
resonant light illuminates a thick cloud of laser-cooled rubidium atoms in
presence of a homogenous magnetic field. We observe new magnetic
field-dependent anisotropies in the CBS signal. We show that the observed
behavior is due to the modification of the atomic radiation pattern by the
magnetic field (Hanle effect in the excited state).Comment: 4 pages, 3 figure
In Vitro Bacterial Contamination of Amniotic Fluid: Effects on Fluorescence Polarization Lung Maturity Testing
Objective: We sought to determine the effect of bacteria on fluorescence polarization (FPOL) testing of amniotic fluid
Monitoring spatially heterogeneous dynamics in a drying colloidal thin film
We report on a new type of experiment that enables us to monitor spatially
and temporally heterogeneous dynamic properties in complex fluids. Our approach
is based on the analysis of near-field speckles produced by light diffusely
reflected from the superficial volume of a strongly scattering medium. By
periodic modulation of an incident speckle beam we obtain pixel-wise ensemble
averages of the structure function coefficient, a measure of the dynamic
activity. To illustrate the application of our approach we follow the different
stages in the drying process of a colloidal thin film. We show that we can
access ensemble averaged dynamic properties on length scales as small as ten
micrometers over the full field of view.Comment: To appear in Soft Material
Centrifugal Modeling of a Pile Under Vertical Random Excitation
Data from the experimental modeling of a pile in a geotechnical centrifuge are compared with analytical results. The model pile was subjected to vertical random excitation with subsequent determination of the compliance function in the frequency domain. This compliance function was found to be consistent with theory. An absorbing boundary was used to minimize reflected wave energy from the centrifuge container boundaries
- …