Atomtronics, the field that envisions assembling circuits and devices out of atomic matter-waves, analogous to electronic components, promises to enable the discovery and understanding of fundamental quantum phenomena as well as realizing exquisite quantum sensors. However, this vision has been an elusive dream for almost 20 years with the explored magnetic trapping platforms, challenged by the sensitivity to fundamental and technical noise of the atoms employed to date, by the difficulty in preserving the matter-wave coherence in the atomic analogs of electronic components, and by limited scalability. A transformational advance is needed to realize atomtronic devices that fulfill their promises.
We are working towards developing a photonic-integrated atomtronics platform based on matter-waves of ultracold strontium that are loaded, trapped, and manipulated above, and along, nanowaveguide photonic circuits as well as nanotapered optical fibers. Specifically, two-color evanescent fields emanating from the top of ridge nanowaveguides or nanofibers generate a potential minimum trapping strontium atoms 200 nm away from the dielectric. Loading the matter waves into these traps is accomplished efficiently with bichromatic blue light at magic wavelengths that are blue- and red-detuned from the microKelvin cooling transition. Pristine nanophotonic potentials, leading to long-lived coherences, are feasible through a novel state-of-the-art aluminum-nitride nanowaveguide and nanotapered fiber platforms suitable for the blue-wavelength spectrum, as required for strontium.
These platforms will enable quantum sensors with unsurpassed sensitivity and far-reaching insights into fundamental quantum optics and atomic physics. Strontium offers several benefits for atomtronics & these platforms.
These highly innovative platforms rely on an interdisciplinary team covering 4 distinct areas of research that will be developed and integrated:
- the understanding, modeling and computation of the Casimir and Casimir-Polder forces that become dominant at such close distances between the atoms and the dielectric surfaces of various compositions and geometries, in collaboration with Dan Steck
- the modelling, design, fabrication and characterization of AlN nanowaveguide photonic and nanotapered fiber devices, in collaboration with Hong Tang and Arno Rauschenbeutel
- the development of an ultracold strontium apparatus suitable for quickly testing and demonstrating these novel platforms, pursued in our labs.
Nanotapered fiber in the lab with 200 nm diameter made by Thomas Hoinkes at U. Berlin, Rauschenbeutel AG, glowing with coupled 461-nm light, now in the loadlock about to be moved to the main chamber 🙂