The key science/technology focus of ATIP is to discover reliable, scalable and efficient ways to control, readout and interact atomic spins on an integrated platform toward demonstrating real-world quantum processors and guided cold atom navigation sensors. Neutral atoms have great potential for those applications due to homogeneous physical properties with long coherence time and lifetime. ATIP offers scalability and flexibility to realize the modular unit of a scalable integrated quantum system with evanescent-field atom traps. Microwave strip-lines can access atomic spins, nanophotonics can collect photons from atoms and trap atoms at the close proximity of the photonics, and atomic spins can be entangled through measurement-induced entanglement and/or Rydberg dipole-dipole interaction. This program is currently funded by the DARPA APhI program and was funded by a DOE LDRD grand challenge.
With ATIP, neutral atoms can be located at 200-nanometer proximity of nanophotonics due to them being free of charge. The small mode area of a waveguide’s evanescent-field enables (1) effective photon collection through the photonic channel, (2) strong atom-light interactions, and (3) low-SWaP (Size, Weight and Power) operation. This is not easy to achieve in other platforms. ATIP is based on membrane nanophotonics and membrane magneto-optical-trap (MOT) structures. The development of ATIP addresses three key innovations: (1) efficient atom loading nearby nanostructures with collision physics, (2) high optical power delivery (>10mW, enough to trap atoms) in vacuum, and (3) efficient and broadband multi-wavelength waveguide coupling. The developed ATIP offers compactness, robustness, manufacturability, and energy efficiency. ATIP uses atomic layer deposition (ALD), transparent alumina membrane film (5mm x 5mm, see the figure). The membrane rib waveguide is suspended on a 500-micrometer center gap in between two silicon needle structures with undercut. This structure can dissipate the heat of optical traps in a vacuum through silicon needles and provide efficient MOT loading into the evanescent-field waveguide atom traps. We are testing the membrane nanophotonics fabricated in Sandia. In addition, the currently available nanofiber testbed enables us to explore further scientific studies in the physical condition analogous to ATIP; we succeeded in trapping atoms and verifying the atomic coherence with evanescent-field trapped atoms.
ATIP’s potential impact is on quantum computing, quantum networks, and cold atom navigation sensors. ATIP can demonstrate an array of single-atom traps with nanophotonic cavities and microwave strip-lines, which can be the reusable core intellectual property (IP) for quantum computing with Rydberg dipole-dipole interaction. In particular, multiple fiber-coupled quantum nodes with ATIP can be simply linked through optical switches for quantum networks. Free-space atom interferometer (AI) sensors have been demonstrated with high performance that match strategic-grade metrics in the laboratory, but have potential issues of performance reduction from rotation and lateral atomic movement in dynamic environments. The guided AI accelerometers with ATIP overcome the issues for dynamic environments, which are sensitive to acceleration of the sensing axis and insensitive to rotation and other acceleration axes. The guided AI gyroscopes sensitive to rotation can be demonstrated with the closed-loop, ring-shaped waveguide using Sagnac phase shift. The guided AI inertial navigation sensors can achieve strategic-grade performance by aiding conventional inertial measurement units (IMU).