NIST Optical Freq. Measurements Group https://www.nist.gov/pml/time-and-frequency-division/optical-frequency-measurements

Laser Frequency Comb Sources and Applications (Scott Diddams, [email protected])

Laser frequency combs involve a unique combination of high- precision control of lightwaves in both the frequency and time domains, with dynamic range extending from microhertz to petahertz and attoseconds to years. This rich field of research builds on the physics and technology of ultrafast light sources that have spectra extending from the UV to the infrared. Achieving such “extreme light” involves a wide range of solid- state laser systems and nonlinear optical techniques, including waveguide, microresonator and nanoscale nonlinear optics in materials with quadratic and cubic nonlinearities. Two particular emphases are understanding and pushing the tech- nical and quantum-limits of these systems, while at the same time realizing practical frequency comb sources that can be used for precision metrology applications such as: optical atomic clocks, fundamental spectroscopy, trace gas sensing, nanoscopy, astronomical spectroscopy, and ultralow noise frequency synthesis.

Nonlinear and Quantum Nanophotonics (Scott Papp, [email protected])

We explore intriguing behaviors of light at the nanoscale, especially using nonlinearity to convert photons from one wavelength to another. Light is a powerful resource for quantum and classical technologies, including optical-frequency measurements, optical communication and information processing, positioning and navigation, signal generation and analysis, and quantum sensing, measurement, and qubit preparation. Using advanced semiconductor nanofabrication techniques, we develop versatile nano- photonics platforms and apply them to directions from conserving energy in hyperscale data centers to realizing a strontium optical clock with integrated photonics. We have an RA opening in experimental AMO physics.

Optical atomic clocks (Andrew Ludlow, [email protected])

Our research focuses on the development of optical clocks using ultracold atomic systems. By tightly confining ytterbium in the virtually-ideal potential of a magic- wavelength optical lattice, the lattice clock pushes the frontiers of atomic timekeeping. We explore enhanced quantum control together with techniques in precision measurement, extreme laser frequency stabilization, Rydberg spectroscopy, and ultra- coherent atom-light interactions to extend state-of-the-art capabilities of the NIST ytterbium lattice clock. We use these extremely precise optical clock systems to explore fundamental physics, like searching for dark matter and beyond-Standard-Model physics. Finally, by developing quantum technologies for a mobile clock apparatus, we aim to unleash the measurement power of optical clocks for applications like mapping Earth's gravity with relativistic geodesy, or metrology for a next-generation definition of the SI unit of the second. More information can be found in: W. McGrew et al., “Atomic clock performance enabling geodesy below the centimeter level,” Nature 564 87 (2018). W. McGrew et al., “Towards the optical second: verifying optical clocks at the SI limit,” Optica 6 448 (2019). M. Schioppo et al., “Ultrastable optical clock with two cold-atom ensembles,” Nat. Photonics 11 48-52 (2017). Optical lattice clock We have an RA opening in experimental AMO physics.