Versatile 1D atomic array around an optical nanofiber created by an accordion lattice

We present our implementation of an optical accordion lattice surrounding an optical nanofiber to establish a 1D atomic array with adaptable inter-atomic distances. Utilizing a 4-f imaging system, we project a 1D phase grating onto the image plane, illuminating the nanofiber from its side. With an aspect ratio of 100, we achieve a 2-mm lattice extension to accommodate an array of approximately 1000 atoms along the nanofiber while maintaining laser power efficiency. The lattice constant is customizable by selecting one of the 250 phase gratings with varying grating constants, all compactly printed on a 2-inch diameter glass substrate. Each grating occupies an area of 100 um * 10 mm. This setup enables comprehensive coverage of lattice constants ranging from 1.0 * 780 nm to 2.5 * 780 nm with a resolution of 5 nm. Fine adjustments to the lattice constant are achieved by tilting the grating within a 5-degree range.

To build an atomic array, optically cooled rubidium atoms are first loaded onto two-color dipole-trap beams guided along the nanofiber, providing transverse and azimuthal confinement. Additionally, the free-space, blue-detuned accordion lattice introduces a longitudinal periodic confinement along the nanofiber. The successful establishment of the 1D array will be validated through Bragg reflection data. We plan to use this platform to study photon-mediated collective phenomena, including super-and-sub radiance transitions, cooperatively generated quantum beats, and long-range non-Markovian dynamics.