40  W, 780  nm laser system with compensated dual beam splitters for atom interferometry

Abstract

We demonstrate a narrow-linewidth 780 nm laser system with up to 40 W power and a frequency modulation bandwidth of 230 MHz. Efficient overlap on nonlinear optical elements combines two pairs of phase-locked frequency components into a single beam. Serrodyne modulation with a high-quality sawtooth waveform is used to perform frequency shifts with > 96.5 % efficiency over tens of megahertz. This system enables next-generation atom interferometry by delivering simultaneous, Stark-shift-compensated dual beam splitters while minimizing spontaneous emission.

Observation of a gravitational Aharonov-Bohm effect

“…In the experiment ( 13 , 14 ), a cloud of 87 Rb is evaporatively cooled to ∼1 μK in a magnetic trap, magnetically lensed to a velocity width of 2 mm/s, and launched into a 10-m vacuum chamber at 13 m/s by an optical lattice. The lattice depth is decreased for a short interval during the launch to release half of the atoms at a lower velocity [see materials and methods for details ( 15 )].…”

Multi-loop atomic Sagnac interferometry

“…The choice of symmetric beam splitting in our geometry suppresses phase noise of the beam splitting lasers, as well as the impact of spatially homogeneous AC-Stark and magnetic field shifts on the two arms of the interferometer 43,44 . We refer to dedicated studies for impacts of light shifts due to large momentum beam splitters 34,41,[55][56][57][58][59] , and isolation or correlation methods to remove vibration noise 47,[60][61][62][63][64][65] for quantum sensors which we expect to be exploited in a future experimental realisation of our concept.…”

“…Showcasing more realistic scenarios, we consider a simple model for losses of atoms and reduction of contrast in dependence on the number of loops as summarised in Table 1 (lower rows). The latter can result from inhomogeneities of the light fields 34,41,[55][56][57][58][59] . Following our calculations and choice of parameters, we still anticipate a compact sensor with a sensitivity of 1.2 × 10 −7 (rad/s)/ √ Hz within a volume of 20 mm 3 for the interferometer, and a highly sensitive, but larger device with 1.7 × 10 −11 (rad/s)/ √ Hz within a meter-sized vacuum vessel based on our method, comparable to the performance of large ring laser gyroscopes 2 .…”

Multi-loop atomic Sagnac interferometry

“…The choice of symmetric beam splitting in our geometry suppresses phase noise of the beam splitting lasers, as well as the impact of spatially homogeneous AC-Stark and magnetic field shifts on the two arms of the interferometer 43 , 44 . We refer to dedicated studies for impacts of light shifts due to large momentum beam splitters 34 , 41 , 55 – 59 , and isolation or correlation methods to remove vibration noise 47 , 60 – 65 for quantum sensors which we expect to be exploited in a future experimental realisation of our concept.…”

“…Showcasing more realistic scenarios, we consider a simple model for losses of atoms and reduction of contrast in dependence on the number of loops as summarised in Table 1 (lower rows). The latter can result from inhomogeneities of the light fields 34 , 41 , 55 – 59 . Following our calculations and choice of parameters, we still anticipate a compact sensor with a sensitivity of within a volume of 20 mm for the interferometer, and a highly sensitive, but larger device with within a meter-sized vacuum vessel based on our method, comparable to the performance of large ring laser gyroscopes 2 .…”