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We report on the first deployment of a ytterbium (Yb) transportable optical lattice clock (TOLC), commercially shipping the clock 3000 km from Boulder, Colorado, to Washington DC. The system, composed of a rigidly mounted optical reference cavity, an atomic physics package, and an optical frequency comb, fully realizes an independent frequency standard for comparisons in the optical and microwave domains. The shipped Yb TOLC was fully operational within 2 days of arrival, enabling frequency comparison with a rubidium (Rb) fountain at the United States Naval Observatory (USNO). To the best of our knowledge, this represents the first deployment of a fully independent TOLC, including the frequency comb, coherently uniting the optical stability of the Yb TOLC to the microwave output of the Rb fountain. 

Grating magneto-optical traps are an enabling quantum technology for portable metrological devices with ultracold atoms. However, beam diffraction efficiency and angle are affected by wavelength, creating a single-optic design challenge for laser cooling in two stages at two distinct wavelengths – as commonly used for loading, e.g., Sr or Yb atoms into optical lattice or tweezer clocks. Here, we optically characterize a wide variety of binary gratings at different wavelengths to find a simple empirical fit to experimental grating diffraction efficiency data in terms of dimensionless etch depth and period for various duty cycles. The model avoids complex 3D light-grating surface calculations, yet still yields results accurate to a few percent across a broad range of parameters. Gratings optimized for two (or more) wavelengths can now be designed in an informed manner suitable for a wide class of atomic species enabling advanced quantum technologies.