High-power and Frequency-Agile Laser System for Gravitational Wave and Dark Matter Detection Using Atom Interferometry (MAGIS-100)

MAGIS-100 is 100-meter-tall atom interferometer currently being built at Fermilab which will leverage modern laser manipulation techniques to search for oscillations in fundamental constants and time-dependent, equivalence-principle-violating accelerations of test masses: key signatures of several ultra-light dark matter candidates. Generation and precise control of meter-separated quantum atomic superpositions within the interferometer requires an agile laser system able to rapidly shift the optical frequency up to a rate of 100 GHz/s while maintaining a phase lock to our static frequency comb. To meet the power requirement of the experiment, two lasers coherently locked must be robust to these rapid frequency shifts. Here, we share test data of our lasers both operating coherently with a 90 % coherence fidelity and reliably surviving the rapid frequency shifts while preserving phase lock. In addition to dark matter searches, the interferometer can adapt toward searches for new fundamental forces outside the Standard Model and tests on the coherence limits of spatially separated wave packets. It will also serve as a prototype gravitational wave detector in frequency band between the peak sensitivities of LIGO and LISA.