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Ultracold atoms exquisitely controlled by lasers are the quantum foundation, particularly for sensing, timekeeping, and computing, of state-of-the-art quantum science and technology. However, the laboratory-scale infrastructure for such optical-atomic quantum apparatuses rarely translates into commercial applications. A promising solution is miniaturizing the optical layouts onto a chip-scale device integrated with cold atoms inside a compact ultra-high vacuum (UHV) chamber. For prototyping purposes, however, rapidly loading or exchanging test photonic devices into a UHV chamber is limited by the evacuation time from atmospheric pressures to the optimal pressures for ultracold atoms of $1\times10^{-11}$ Torr, a process typically taking weeks or months without cryogenics. Here, we present a loadlock apparatus and loading procedure capable of venting, exchanging, and evacuating back to $<1\times10^{-11}$ Torr in under 24 hours. Our system allows for rapid testing and benchmarking of various photonic devices with ultracold atoms.

Neutral atoms trapped in the evanescent optical potentials of nanotapered optical fibers are a promising platform for developing quantum technologies and exploring fundamental science, such as quantum networks and quantum electrodynamics. Building on the successful advancements with trapped alkali atoms, here we demonstrate a state-insensitive optical dipole trap for strontium-88, an alkaline-earth atom, using the evanescent fields of a nanotapered optical fiber. Leveraging the low laser-cooling temperatures of $\sim\!\!1~\mu$K readily achievable with strontium, we demonstrate trapping in record low trap depths corresponding to $\sim\!\!3~\mu$K. Further, employing a double magic wavelength trapping scheme, we realize state-insensitive trapping on the kilohertz-wide $5s^{2}\;^{1}\!S_{0}-5s5p\;^{3}\!P_{1,|m|=1}$ cooling transition, which we verify by performing near-surface high-resolution spectroscopy of the atomic transition. This allows us to experimentally find and verify the state insensitivity of the trap nearby a theoretically predicted magic wavelength of 435.827(25) nm. Given the non-magnetic ground state and low collisional scattering length of strontium-88, this work also lays the foundation for developing versatile and robust matter-wave atomtronic circuits over nanophotonic waveguides., Comment: 14 pages, 15 figures