CSU Physics Colloquium
Timekeeping for Tomorrow: Atomic Clocks using Ultracold Atoms in an Optical Lattice
Dr. Andrew Ludlow
National Institute of Standards and Technology
Mon, 11/9
Abstract: Atomic clocks find significant roles in a number of scientific and technological settings. One interesting approach to a next-generation clock utilizes alkaline earth atoms confined in an optical lattice. Strong confinement of the atoms eliminates motional effects which otherwise trouble the interrogation of the electronic transition at the heart of the clock. At the same time, the optical lattice equally perturbs the two electronic clock states so that the confinement introduces a net zero shift of the natural transition frequency. Here I describe the design and realization of optical frequency standards using 87Sr and 171Yb, among the most common choices worldwide for the development of these types of standards. With an ultra-stable laser light source, atomic spectral linewidths of the optical clock transition are observed below 2 Hz. High accuracy spectroscopy of the clock transition is carried out utilizing a frequency comb referenced to the NIST-F1 Cs fountain clock. Remote comparison of the Sr system at JILA and the Yb system at NIST enables frequency measurements at a fractional level below 1 part in 1016. The performance of these state-of-the-art systems is discussed, as well as how these systems will improve in the upcoming years.