A fibered laser system for the MIGA large scale atom interferometer

Abstract

We describe the realization and characterization of a compact, autonomous fiber laser system that produces the optical frequencies required for laser cooling, trapping, manipulation, and detection of 87 Rb atoms -a typical atomic species for emerging quantum technologies. This device, a customized laser system from the Muquans company, is designed for use in the challenging operating environment of the Laboratoire Souterrain à Bas Bruit (LSBB) in France, where a new large scale atom interferometer is being constructed underground -the MIGA antenna. The mobile bench comprises four frequency-agile C-band Telecom diode lasers that are frequency doubled to 780 nm after passing through high-power fiber amplifiers. The first laser is frequency stabilized on a saturated absorption signal via lock-in amplification, which serves as an optical frequency reference for the other three lasers via optical phase-locked loops. Power and polarization stability are maintained through a series of custom, flexible micro-optic splitter/combiners that contain polarization optics, acousto-optic modulators, and shutters. Here, we show how the laser system is designed, showcasing qualities such as reliability, stability, remote control, and flexibility, while maintaining the qualities of laboratory equipment. We characterize the laser system by measuring the power, polarization, and frequency stability. We conclude with a demonstration using a cold atom source from the MIGA project and show that this laser system fulfills all requirements for the realization of the antenna. This laser system system, based on reliable telecommunications technology, has applications toward mobile, field deployable quantum technologies.Pioneering experiments in matter-wave interferometry 5-7 demonstrating inertial sensitivity led to significant interest for precision measurements using atomic beamlines. Development of laser-cooling schemes 8-11 during the last thirty years have produced a series of methods to produce small 3D kinetic temperatures in dilute atomic gases. This led to atom interferometry with cold atoms, which has a track record of accuracy and precision spanning the development of laser cooling. This technique has been used to measure gravity 12-17 , gravity gradients 18,19 , rotations 20-24 , measurements of the gravitational constant G 25, 26 , determination of the fine structure constant coupled with tests of quantum electrodynamics 27, 28 , studies of the interface between gravity and quantum mechanics 29, 30 , General Relativity (GR) tests such as the searches for violations of the Weak Equivalence Principle 31-37 , tests of local Lorentz invariance of post-Newtonian gravity 38 , experiments in microgravity 39-41 , tests of dark energy 42,43 , and recoil associated with blackbody radiation 44 . Based on this record of precision measurements, cold atom interferometry gained traction as a candidate system for observing Gravitational Waves (GWs) at low frequency [45][46][47][48][49][50][51] . The schemes developed in these experiments form ...

High-accuracy inertial measurements with cold-atom sensors

“…The five optical frequencies needed to perform a coldatom inertial sensor are represented in figure 3, for 87 Rb interferometers based on Raman transitions. A variety of different laser systems have been developed and published, with different number of lasers, ranging from five to only one, with designs constrained by the size, the final application, the measurement environment conditions and the evolution of technologies [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42] . Figure 4 displays a compact free space optical system and a complete architecture of a fibered optical bench which reached a Technology Readiness Level (TRL) of 4 (Ref.…”

The NEWTON-g Gravity Imager: Toward New Paradigms for Terrain Gravimetry

“…Etna. First, frequency-doubled telecom lasers are employed to cool and manipulate the atoms (Ménoret et al, 2011;Lévèque et al, 2014;Theron et al, 2015;Caldani et al, 2019;Sabulsky et al, 2020). This means that the laser system is completely fibered, and intrinsically very compact and immune to external perturbations, while ensuring a high level of performance.…”

Carrier-Suppressed Multiple Single-Sideband Laser Source for Atom Cooling and Interferometry

“…Telecom frequency-based architectures afford the strength of extensive development with reliable and robust off-the-shelf components and can be frequency doubled using a periodically-poled lithium-niobate (PPLN) crystal [19]. Within the scope of all-fibered laser systems designed for laser cooling and atom interferometry, several configurations have been demonstrated.…”