Robust Atom Optics for Large Momentum Transfer Atom Interferometry with Strontium-88

Large momentum transfer (LMT) atom interferometry requires atom optics with near unity population transfer and stable phase control, which are limited by noise factors such as thermal cloud expansion, stray magnetic fields, and laser fluctuations. To allow greater momentum transfer under a broad range of experimental conditions, we use the quantum optimal control Python toolkit developed by Q-CTRL to engineer amplitude and phase-modulated pulses for the 461 nm (multi-photon Bragg) and 689 nm (single-photon) transitions of Sr-88. We have simulated π-pulses maintaining over 99.9% population transfer and phase stability across several static and time-dependent noise channels, which couple as power, frequency, and polarization errors. These are more robust at a given laser power without exceeding the duration of typical Gaussian and composite pulses. We also report on progress towards implementation of the 689 nm pulses for point-source interferometry (PSI) with a hot (~1 mK) cloud [1][2]. The 6W output from a pair of Ti:sapphire lasers is shaped into arbitrary pulses via AOMs driven by a quadrature modulated rf signal. Such pulses could later be used as wavefront diagnostics during operation of colder interferometers such as MAGIS-100 [3].

-[1] Dickerson et al. Phys. Rev. Lett. 111 083001 (2013)

-[2] Rudolph et al. Phys. Rev. Lett. 124 083604 (2020)

-[3] Abe et al. Quantum Sci. Technol. 6 044003 (2021)