1,849 research outputs found
S. H. Ludlow to Mr. and Mrs. Aldrich, 18 December 1872
https://egrove.olemiss.edu/aldrichcorr_e/1034/thumbnail.jp
Quantum engineering of atomic phase-shifts in optical clocks
Quantum engineering of time-separated Raman laser pulses in three-level
systems is presented to produce an ultra-narrow optical transition in bosonic
alkali-earth clocks free from light shifts and with a significantly reduced
sensitivity to laser parameter fluctuations. Based on a quantum artificial
complex-wave-function analytical model, and supported by a full density matrix
simulation including a possible residual effect of spontaneous emission from
the intermediate state, atomic phase-shifts associated to Ramsey and
Hyper-Ramsey two-photon spectroscopy in optical clocks are derived. Various
common-mode Raman frequency detunings are found where the frequency shifts from
off-resonant states are canceled, while strongly reducing their uncertainties
at the 10 level of accuracy.Comment: accepted for publication in PR
Fluorescence measurements of expanding strongly-coupled neutral plasmas
We report new detailed density profile measurements in expanding
strongly-coupled neutral plasmas. Using laser-induced fluorescence techniques,
we determine plasma densities in the range of 10^5 to 10^9/cm^3 with a time
resolution limit as small as 7 ns. Strong-coupling in the plasma ions is
inferred directly from the fluorescence signals. Evidence for strong-coupling
at late times is presented, confirming a recent theoretical result.Comment: submitted to PR
Narrow Line Photoassociation in an Optical Lattice
With ultracold Sr in a 1D magic wavelength optical lattice, we
performed narrow line photoassociation spectroscopy near the SP intercombination transition. Nine least-bound vibrational molecular
levels associated with the long-range and potential energy surfaces
were measured and identified. A simple theoretical model accurately describes
the level positions and treats the effects of the lattice confinement on the
line shapes. The measured resonance strengths show that optical tuning of the
ground state scattering length should be possible without significant atom
loss.Comment: 4 pages, 4 figure
Two-photon absorption in potassium niobate
We report measurements of thermal self-locking of a Fabry-Perot cavity
containing a potassium niobate (KNbO3) crystal. We develop a method to
determine linear and nonlinear optical absorption coefficients in intracavity
crystals by detailed analysis of the transmission lineshapes. These lineshapes
are typical of optical bistability in thermally loaded cavities. For our
crystal, we determine the one-photon absorption coefficient at 846 nm to be
(0.0034 \pm 0.0022) per m and the two-photon absorption coefficient at 846 nm
to be (3.2 \pm 0.5) \times 10^{-11} m/W and the one-photon absorption
coefficient at 423 nm to be (13 \pm 2) per m. We also address the issue of
blue-light-induced-infrared-absorption (BLIIRA), and determine a coefficient
for this excited state absorption process. Our method is particularly well
suited to bulk absorption measurements where absorption is small compared to
scattering. We also report new measurements of the temperature dependence of
the index of refraction at 846 nm, and compare to values in the literature.Comment: 8 pages. To appear in J. Opt. Soc. Am.
Making optical atomic clocks more stable with level laser stabilization
The superb precision of an atomic clock is derived from its stability. Atomic
clocks based on optical (rather than microwave) frequencies are attractive
because of their potential for high stability, which scales with operational
frequency. Nevertheless, optical clocks have not yet realized this vast
potential, due in large part to limitations of the laser used to excite the
atomic resonance. To address this problem, we demonstrate a cavity-stabilized
laser system with a reduced thermal noise floor, exhibiting a fractional
frequency instability of . We use this laser as a stable
optical source in a Yb optical lattice clock to resolve an ultranarrow 1 Hz
transition linewidth. With the stable laser source and the signal to noise
ratio (S/N) afforded by the Yb optical clock, we dramatically reduce key
stability limitations of the clock, and make measurements consistent with a
clock instability of
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