High-resolution Spectroscopy With Femtosecond Optical Combs

A stabilized femtosecond frequency comb has ∼106 stable optical modes spanning hundreds of terahertz, making it an ideal tool for high-resolution spectroscopy. We demonstrate some features of frequency-comb spectroscopy using experiments involving calcium and cesium. © OSA.Oskay, W.H., Diddams, S.A., Donley, E.A., Fortier, T.M., Heavner, T.P., Hollberg, L., Itano, W.M., Bergquist, J.C., Single-atom optical clock with high accuracy (2006) Phys. Rev. Lett, 97, pp. 020801/1-020801/4Fortier, T.M., Bartels, A., Diddams, S.A., Octave-spanning Ti:sapphire laser with a repetition rate >1 GHz for optical frequency measurements and comparisons (2006) Opt. Lett, 31, pp. 1011-1013Jones, D.J., Diddams, S.A., Ranka, J.K., Stentz, A., Windeler, R.S., Hall, J.L., Cundiff, S.T., Carrier-envelope phase control of femtosecond mode-locked lasers and direct optical frequency synthesis (2000) Science, 288, pp. 635-639Fortier, T.M., Le Coq, Y., Stalnaker, J.E., Ortega, D., Diddams, S.A., Oates, C.W., Hollberg, L., Kilohertz-resolution spectroscopy of cold atoms with an optical frequency comb (2006) Phys. Rev. Lett, 97, pp. 163905/1-163905/4Oates, C.W., Bondu, F., Fox, R.W., Hollberg, L., A diode-laser optical frequency standard based on laser-cooled Ca atoms: Sub-kilohertz spectroscopy by optical shelving detection (1999) Eur. Phys. J. D, 7, pp. 449-460Degenhardt, C., Stoehr, H., Lisdat, C., Wilpers, G., Schnatz, H., Lipphardt, B., Nazarova, T., Riehle, F., Calcium optical frequency standard with ultracold atoms: Approaching 10-15 relative uncertainty (2005) Phys. Rev. A, 72, pp. 062111/1-062111/1

Towards measuring nuclear-spin-dependent and isotopic-chain atomic parity violation in ytterbium

We discuss experiments aimed at measurements of atomic parity nonconservation (PNC) effects in the 1S0-3D1 transition (408 nm) in atomic Ytterbium (Z=70). According to theoretical predictions, the PNC-induced E1 amplitude of this transition is ~100 times larger than the analogous amplitude in Cs. Such an experiment will determine differences in PNC effects between different hyperfine components for odd-neutron-number Yb isotopes and, thereby, will allow measurements of the nuclear anapole moments in nuclei with unpaired neutrons. In addition, measurements of PNC in different isotopes would give information on neutron distributions within the nuclei. The apparatus designed and built for this experiment is described, and results of measurements towards understanding of systematic effects influencing the accuracy, and the current status of the ongoing PNC measurements are presented

Analysis method for detecting topological defect dark matter with a global magnetometer network

© 2020The Global Network of Optical Magnetometers for Exotic physics searches (GNOME) is a network of time-synchronized, geographically separated, optically pumped atomic magnetometers that is being used to search for correlated transient signals heralding exotic physics. GNOME is sensitive to exotic couplings of atomic spins to certain classes of dark matter candidates, such as axions. This work presents a data analysis procedure to search for axion dark matter in the form of topological defects: specifically, walls separating domains of discrete degenerate vacua in the axion field. An axion domain wall crossing the Earth creates a distinctive signal pattern in the network that can be distinguished from random noise. The reliability of the analysis procedure and the sensitivity of the GNOME to domain-wall crossings are studied using simulated data11sciescopu