226 research outputs found
Towards optimization of pulsed sodium laser guide stars
Pulsed sodium laser guide stars (LGS) are useful because they allow for
Rayleigh blanking and fratricide avoidance in multiple-LGS systems.
Bloch-equation simulations of sodium-light interactions show that these may be
able to achieve photon returns nearly equal to, and in some cases greater than,
what is seen from continuous-wave (CW) excitation. In this work, we study the
time-dependent characteristics of sodium fluorescence, and investigate the
optimal format for the new fiber laser LGS that will be part of the upgraded
adaptive optics (AO) system on the Shane telescope at Mt. Hamilton. Results of
this analysis are examined in the context of their general applicability to
other LGS systems and the potential benefits of uplink correction are
considered. Comparisons of simulation predictions with measurements from
existing LGS are also presented and discussed.Comment: 9 pages, 7 figures, accepted by JOSA
Variable Free Spectral Range Spherical Mirror Fabry-Perot Interferometer
A spherical Fabry-Perot interferometer with adjustable mirror spacing is used
to produce interference fringes with frequency separation (c/2L)/N, N=2-15. The
conditions for observation of these fringes are derived from the consideration
of the eigenmodes of the cavity with high transverse indices.Comment: 11 pages, 7 figures, accepted to Siberian Journal of Physic
Magneto-Optical Cooling of Atoms
We propose an alternative method to laser cooling. Our approach utilizes the
extreme brightness of a supersonic atomic beam, and the adiabatic atomic
coilgun to slow atoms in the beam or to bring them to rest. We show how
internal-state optical pumping and stimulated optical transitions, combined
with magnetic forces can be used to cool the translational motion of atoms.
This approach does not rely on momentum transfer from photons to atoms, as in
laser cooling. We predict that our method can surpass laser cooling in terms of
flux of ultra-cold atoms and phase-space density, with lower required laser
power and reduced complexity
Relaxation of atomic polarization in paraffin-coated cesium vapor cells
The relaxation of atomic polarization in buffer-gas-free, paraffin-coated
cesium vapor cells is studied using a variation on Franzen's technique of
``relaxation in the dark'' [Franzen, Phys. Rev. {\bf 115}, 850 (1959)]. In the
present experiment, narrow-band, circularly polarized pump light, resonant with
the Cs D2 transition, orients atoms along a longitudinal magnetic field, and
time-dependent optical rotation of linearly polarized probe light is measured
to determine the relaxation rates of the atomic orientation of a particular
hyperfine level. The change in relaxation rates during light-induced atomic
desorption (LIAD) is studied. No significant change in the spin relaxation rate
during LIAD is found beyond that expected from the faster rate of spin-exchange
collisions due to the increase in Cs density.Comment: 14 pages, 14 figure
Tailorable dispersion in a four-wave mixing laser
We present experimental results demonstrating controllable dispersion in a ring laser by monitoring the lasing-frequency response to cavity-length variations. Pumping on an N-type level configuration in Rb-87, we tailor the intra- cavity dispersion slope by varying experimental parameters, such as pump-laser frequency, atomic density, and pump power. As a result, we can tune the pulling factor, i.e., the ratio of the laser frequency shift to the empty cavity frequency shift, of our laser by more than an order of magnitude. (C) 2017 Optical Society of Americ
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