Tue March 11, 2014 4:00 pm
Improving the tick-tock of an optical atomic clock: atomic timing at the state-of-the-art
Location:MIT 26-214
Dr. Andrew Ludlow,
NIST - University of Colorado - Boulder
Optical atomic clocks are next-generation timekeepers promising new capability in the measurement of time and frequency. With applications ranging from the exploration of fundamental laws of physics to advanced synchronization and geodetic measurements, the ability to measure time at one part in 1018offers exciting prospects. One type of optical clock, the optical lattice clock, has seen rapid progress since its birth one decade ago and today several key advances are being explored worldwide. These will be broadly discussed, with focus on the ytterbium optical lattice clock developed at NIST. Our recent efforts to overcome deleterious measurement effects in the lattice clock have led to clock stability near the standard quantum limit, realizing a timing precision of 1.6 parts in 1018. Large atomic ensembles trapped in the magic wavelength optical lattice have the potential to be even better, and I will discuss steps to higher performance still. Another challenging problem facing the optical lattice clock is reducing and controlling environmental perturbations which influence the accuracy of these standards. As a prominent example, the largest perturbative effect on a lattice clock stems from thermal blackbody radiation which bathes the lattice trapped atoms, inducing a Stark shift on the narrowband electronic transition being probed. I will describe recent efforts that now enable control of this effect at the desired level (10-18 clock uncertainty).