30 research outputs found
Channelization architecture for wide-band slow light in atomic vapors
We propose a ``channelization'' architecture to achieve wide-band
electromagnetically induced transparency (EIT) and ultra-slow light propagation
in atomic Rb-87 vapors. EIT and slow light are achieved by shining a strong,
resonant ``pump'' laser on the atomic medium, which allows slow and
unattenuated propagation of a weaker ``signal'' beam, but only when a
two-photon resonance condition is satisfied. Our wideband architecture is
accomplished by dispersing a wideband signal spatially, transverse to the
propagation direction, prior to entering the atomic cell. When particular
Zeeman sub-levels are used in the EIT system, then one can introduce a magnetic
field with a linear gradient such that the two-photon resonance condition is
satisfied for each individual frequency component. Because slow light is a
group velocity effect, utilizing differential phase shifts across the spectrum
of a light pulse, one must then introduce a slight mismatch from perfect
resonance to induce a delay. We present a model which accounts for diffusion of
the atoms in the varying magnetic field as well as interaction with levels
outside the ideal three-level system on which EIT is based. We find the maximum
delay-bandwidth product decreases with bandwidth, and that delay-bandwidth
product ~1 should be achievable with bandwidth ~50 MHz (~5 ns delay). This is a
large improvement over the ~1 MHz bandwidths in conventional slow light systems
and could be of use in signal processing applications.Comment: Published in SPIE Proceedings, Photonics West 2005 (San Jose, CA,
Jan. 22-27, 2005
COVID-19 pandemic waves surveillance in another severe winter of 2021: a basic guide to understand epidemic contexts, interpret pandemic waves and trends, ahead of the curve: how can we understand and interpret alert signals from pandemic waves considering pitfalls and stay ahead of the virus?
publishersversionpublishe
ASPHER Statement: Facing the Fourth Winter of the COVID-19 Pandemic
From Frontiers via Jisc Publications RouterHistory: collection 2022, received 2022-09-14, accepted 2022-09-20, epub 2022-10-03Peer reviewed: TruePublication status: Publishe
ASPHER Statement: Planning for Winter 2022-23
From Frontiers via Jisc Publications RouterHistory: collection 2022, received 2022-09-14, accepted 2022-09-20, epub 2022-10-03Peer reviewed: TrueAcknowledgements: Thanks to Catarina Hermenegildo, Catolica University, Lisbon, Portugal.Publication status: Publishe
Nonlinear optical parametric processes in liquids and gases
Nonlinear Optical Parametric Processes in Liquids and Gase
Food and feeding habits of the yellowfin tuna Neothunnus macropterus in relation to its distribution in the central Pacific region
Typescript.Literature cited: leaves 62-69.vi, 69 leaves graphs, mapFood and feeding habits of the yellowfin tuna Neothunnus macropterus in relation to its distribution in the central Pacific region. Examination of length, frequency distribution, of all yellowfin measured from various fishing methods. Examines stomach contents, stomach size, prey and predator habitat variation