676 research outputs found
Large negative and positive delay of optical pulses in coherently prepared dense Rb vapor with buffer gas
We experimentally study the group time delay for a light pulse propagating
through hot Rb vapor in the presence of a strong coupling field in a
configuration. We demonstrate that the ultra-slow pulse propagation is
transformed into superluminal propagation as the one-photon detuning of the
light increases due to the change in the transmission resonance lineshape.
Negative group velocity as low as -c/10^6=-80 m/s is recorded. We also find
that the advance time in the regime of the superluminal propagation grows
linearly with increasing laser field power.Comment: 5 pages, 6 figure
Observation of polarization quantum noise of laser radiation in Rb vapor cell
We present experimental study of polarization quantum noise of laser
radiation passed through optically think vapor of Rb87. We observe a step-like
noise spectrum. We discuss various factor which may result in such noise
spectrum and prevent observation of squeezing of quantum fluctuations predicted
in Matsko et al. PRA 63, 043814 (2001).Comment: 4 pages, 5 figures. Translated from Russian by I. Novikov
EIT and diffusion of atomic coherence
We study experimentally the effect of diffusion of Rb atoms on
Electromagnetically Induced Transparency (EIT) in a buffer gas vapor cell. In
particular, we find that diffusion of atomic coherence in-and-out of the laser
beam plays a crucial role in determining the EIT resonance lineshape and the
stored light lifetime.Comment: 5 pages, 8 figure
Identification of Escherichia coli K12 YdcW protein as a γ-aminobutyraldehyde dehydrogenase
Abstractγ-Aminobutyraldehyde dehydrogenase (ABALDH) from wild-type E. coli K12 was purified to apparent homogeneity and identified as YdcW by MS-analysis. YdcW exists as a tetramer of 202±29kDa in the native state, a molecular mass of one subunit was determined as 51±3kDa. Km parameters of YdcW for γ-aminobutyraldehyde, NAD+ and NADP+ were 41±7, 54±10 and 484±72μM, respectively. YdcW is the unique ABALDH in E. coli K12. A coupling action of E. coli YgjG putrescine transaminase and YdcW dehydrogenase in vitro resulted in conversion of putrescine into γ-aminobutyric acid
Optimal control of light pulse storage and retrieval
We demonstrate experimentally a procedure to obtain the maximum efficiency
for the storage and retrieval of light pulses in atomic media. The procedure
uses time reversal to obtain optimal input signal pulse-shapes. Experimental
results in warm Rb vapor are in good agreement with theoretical predictions and
demonstrate a substantial improvement of efficiency. This optimization
procedure is applicable to a wide range of systems.Comment: 5 pages, 4 figure
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