1,721,032 research outputs found
Radiation pressure on a moving body: Beyond the Doppler effect
No full textCopyright © 2012 Optical Society of AmericaThis paper was published in Journal of the Optical Society of America B and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/josab/abstract.cfm?uri=josab-29-11-3136. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.The dependence of macroscopic radiation pressure on the velocity of the object being pushed is commonly attributed to the Doppler effect. This need not be the case, and here we highlight velocity-dependent radiation pressure terms that have their origins in the mixing of s and p polarizations brought about by the Lorentz transformation between the lab and the material rest frame, rather than in the corresponding transformation of frequency and wavevector. The theory we develop may be relevant to the nano-optomechanics of moving bodies
Self-similar scaling in the coherent dynamics of ultracold atoms
No full textWell-resolved and long-lived atomic Bloch oscillations provide straightforward access to intriguing yet fascinating self-similar patterns. These could be observed in the quasienergy spectra of ultracold atomic wave packets subject to gravity in a driven optical lattice potential. As for the Hofstadter butterflylike energy spectra of crystal electrons in a uniform magnetic field, these atomic quasienergy spectra are shown to originate from commensurability between the Bloch oscillations period and the lattice driving period
Laser assisted Cherenkov emission in resonant media
No full textWe theoretically examine the behaviour of Cherenkov radiation in a lossy, dispersive and resonant medium when emission is assisted by an external electromagnetic field. Under the appropriate coherence conditions for Cherenkov emission, we anticipate a large increase of the emission yield at resonance. Our predictions are implemented by numerical estimates for cuprous oxide (Cu2O)
All-optical light confinement in dynamic cavities
No full textWe show how to realize in a cold atomic sample a dynamic magneto-optically controlled cavity in
which a slow-light pulse can be confined and released on demand. The probe optical pulse is retrieved
from the atomic spin coherence initially stored within the cavity and is subsequently confined there
subject to a slow-light regime with little loss and diffusion for time intervals as long as a few hundred
microseconds before being extracted from either side of the cavity. Our proof-of-principle scheme
illustrates the underlying physics of this new mechanism for coherent light confinement and manipulation
in cold atoms. This may ease the realization of nonlinear interactions between weak light pulses where
strong atom-photon interactions are required for quantum information processing
Decay of stationary light pulses in ultracold atoms
No full textstanding-wave electromagnetically induced transparency. We rely on full numerical solutions of the Maxwell-
Liouville equations without invoking secular and adiabatic approximations and arbitrary initial state assumptions.
These approximations and assumptions can conceal, e.g., significant loss and diffusion responsible for the decay
of stationary light pulses in cold atomic samples. The complex decay dynamics of a stationary light pulse is
here analyzed in terms of higher-order spin and optical coherences that arise from nonlinear interactions of the
stationary light pulse with the two counterpropagating components of a standing-wave driving field. Specific
results for stationary light pulses in cold 87Rb atoms have been discussed for temperature regimes where the
residual Doppler broadening is negligible
"Electromagnetic induced transparency of Wannier-Mott excitons"
No full textWe predict a remarkable quenching of the absorption due to electromagnetic-induced transparency in an undoped bulk semiconductor. For free-exciton lines the effect is expected to be as large as that observed in atomic systems. The conditions for its occurrence are determined and numerical estimates are presented for the specific case of the "yellow" exciton of Cu2O
"Highly anomalous group velocity of light in ultracold rubidium gases"
No full textDilute rubidium gases at submicrokelvin temperatures offer the possibility of exceptionally small and negative group velocities. We devise an experimental scheme in which nearly dispersionless and highly superluminal pulse propagation at optical frequencies can be observed. Comparisons with other schemes and potential applications are briefly discussed
A singular light dragging effect
No full textWe discuss the phenomenon of upstream bending of a light ray and we anticipate that such an anomalous effect can be observed in a coherently driven sample of cuprous oxide (Cu2O). We here examine the material parameters and the driving configurations that lead to upstream bendings of considerable magnitude
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