24 research outputs found
Precise measurement of hyperfine intervals using avoided crossing of dressed states
We demonstrate a technique for precisely measuring hyperfine intervals in
alkali atoms. The atoms form a three-level system in the presence of
a strong control laser and a weak probe laser. The dressed states created by
the control laser show significant linewidth reduction. We have developed a
technique for Doppler-free spectroscopy that enables the separation between the
dressed states to be measured with high accuracy even in room-temperature
atoms. The states go through an avoided crossing as the detuning of the control
laser is changed from positive to negative. By studying the separation as a
function of detuning, the center of the level-crossing diagram is determined
with high precision, which yields the hyperfine interval. Using
room-temperature Rb vapor, we obtain a precision of 44 kHz. This is a
significant improvement over the current precision of ~ 1 MHz.Comment: 4 pages, 4 figures. To be published shortly in Europhysics Letter
Doppler-free spectroscopy in driven three-level systems
We demonstrate two techniques for studying the features of three-level
systems driven by two lasers (called control and probe), when the transitions
are Doppler broadened as in room-temperature vapor. For -type systems,
the probe laser is split to produce a counter-propagating pump beam that
saturates the transition for the zero-velocity atoms. Probe transmission then
shows Doppler-free peaks, which can even have sub-natural linewidth. For V-type
systems, the transmission of the control beam is detected as the probe laser is
scanned. The signal shows Doppler-free peaks when the probe laser is resonant
with transitions for the zero-velocity group. Both techniques greatly simplify
the study of three-level systems since theoretical predictions can be directly
compared without complications from Doppler broadening and the presence of
multiple hyperfine levels in the spectrum.Comment: 6 pages, 5 figure
Precise measurement of hyperfine structure in the state of Rb
We demonstrate a technique to measure hyperfine structure using a
frequency-stabilized diode laser and an acousto-optic modulator locked to the
frequency difference between two hyperfine peaks. We use this technique to
measure hyperfine intervals in the state of Rb and obtain a
precision of 20 kHz. We extract values for the magnetic-dipole coupling
constant MHz and the electric-quadrupole coupling constant
MHz. These values are a significant improvement over previous
results.Comment: 4 pages, 4 figure
Laser cooling and trapping of Yb from a thermal source
We have successfully loaded a magneto-optic trap for Yb atoms from a thermal
source without the use of a Zeeman slower. The source is placed close to the
trapping region so that it provides a large flux of atoms that can be cooled
and captured. The atoms are cooled on the
transition at 398.8 nm. We have loaded all seven stable isotopes of Yb into the
trap. For the most abundant isotope (Yb), we load more than
atoms into the trap within 1 s. For the rarest isotope (Yb) with a
natural abundance of only 0.13%, we still load about atoms into
the trap. We find that the trap population is maximized near a detuning of
and field gradient of 75 G/cm.Comment: 4 figures, 6 page
Direct measurement of the fine-structure interval in alkali atoms using diode lasers
We demonstrate a technique for directly measuring the fine-structure interval
in alkali atoms using two frequency-stabilized diode lasers. Each laser has a
linewidth of order 1 MHz and precise tunability: one laser is tuned to a
hyperfine transition in the D_1 line, and the other laser to a hyperfine
transition in the D_2 line. The outputs of the lasers are fed into a scanning
Michelson interferometer that measures the ratio of their wavelengths
accurately. To illustrate the technique, we measure the fine-structure interval
in Rb, and obtain a value of 237.6000(3)(5) cm^-1 for the hyperfine-free
5P_{3/2} - 5P_{1/2} interval.Comment: 3 pages, 2 figures, to be published in Applied Physics Letters, 20
May 2002 editio
High-accuracy wavemeter based on a stabilized diode laser
We have built a high-accuracy wavelength meter for tunable lasers using a
scanning Michelson interferometer and a reference laser of known wavelength.
The reference laser is a frequency stabilized diode laser locked to an atomic
transition in Rb. The wavemeter has a statistical error per measurement of 5
parts in which can be reduced considerably by averaging. Using a second
stabilized diode laser, we have verified that systematic errors are below 4
parts in .Comment: 3 pages, 2 figure