An evaluation procedure for scanning interferometer based wavemeters

2004

Abstract A common approach to wavelength measurement is the travelling interferometer (wavemeter). We present an evaluation procedure that allows to achieve high precision with a compact device. The zero crossings of the interference signal corresponding to the reference laser is used to sample the signal of the probe laser. Electronic noise and fluctuations of the laser frequency cancel due to the large number of sample points. The evaluation procedure has been applied to a wavemeter based on a continuously moving Mach–Zehnder interferometer. A travelling path of 10 cm was sufficient to yield 3σ-accuracy of Δ λ / λ =3.2×10 −9 , demonstrated by comparison with cesium saturation spectroscopy.

Isotope-shift measurements of stable and short-lived lithium isotopes for nuclear-charge-radii determination

2010

Changes in the mean-square nuclear charge radii along the lithium isotopic chain were determined using a combination of precise isotope shift measurements and theoretical atomic structure calculations. Nuclear charge radii of light elements are of high interest due to the appearance of the nuclear halo phenomenon in this region of the nuclear chart. During the past years we have developed a new laser spectroscopic approach to determine the charge radii of lithium isotopes which combines high sensitivity, speed, and accuracy to measure the extremely small field shift of an 8 ms lifetime isotope with production rates on the order of only 10,000 atoms/s. The method was applied to all bound iso…

Convex bodies and convexity on Grassmann cones

1962

Absolute frequency measurements on the 2S→3S transition of lithium-6,7

2009

The frequencies of the 2S–3S two-photon transition for the stable lithium isotopes were measured by cavity-enhanced Doppler-free laser excitation that was controlled by a femtosecond frequency comb. The resulting values of 815 618 181.57(18) and 815 606 727.59(18) MHz, respectively, for 7Li and 6Li are in agreement with previous measurements but are more accurate by an order of magnitude. There is still a discrepancy of about 11.6 and 10.6 MHz from the latest theoretical values. This is comparable to the uncertainty in the theoretical calculations, while uncertainty in our experimental values is more than a hundred-fold smaller. More accurate theoretical calculation of the transition freque…