Optical Aberration and Laser Pointing Jitter Mitigation for MAGIS-100*

MAGIS-100 is a 100 meter baseline atom interferometer which will search for wavelike dark matter, serve as a prototype gravitational wave detector in the 0.3-3 Hz frequency range, and realize large scale quantum superpositions. The interferometer will be assembled in the vertical MINOS access shaft at Fermilab, and will be mediated by a single-photon transition on the clock resonance of strontium. The space-time area enclosed by the interferometer arms can be increased with large momentum transfer pulse sequences, but jitter in the pointing of the interferometer beam and inhomogeneity in the laser phase and intensity profiles can limit the total number of pulses that can be performed. We present a design of the beam delivery system for MAGIS-100 which provides spatial mode cleaning by free-space in-vacuum propagation, minimizes subsequent induced aberrations with ultra-high-quality in-vacuum optics, provides Coriolis force compensation with piezo-controlled tip-tilt mirrors, and uses stable support structures to suppress the pointing jitter and frequency noise response of the interferometer beam from seismic drives.