Laser Beam Delivery for 100-Meter Baseline Clock Atom Interferometry (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, where an 8 W laser will split the wave function of strontium atom clouds via the 698nm clock resonance. The ultimate sensitivity of the apparatus is limited in part by jitter in the pointing of this interferometer laser, aberrations in its wavefront, and Coriolis forces emerging from the rotation of the earth. We present the design and a prototype test of the beam delivery system for MAGIS-100, which provides spatial mode cleaning by free-space in-vacuum propagation, minimizes subsequently 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 and frequency jitter of the interferometer laser caused by seismic drives.