A compact continuous matter wave accelerometer
Abstract
A compact continuous matter wave accelerometerAccelerometers based on matter wave interferometers are typically complex devices requiring alarge volume to accommodate the free fall of atoms and complicated systems to control multiplelasers for cooling, interferometry, and detection. The most sensitive devices use pulsed atomicfountains which have significant dead time and low bandwidth. In this proposal we willimplement a proposed method based on optical detection of Bloch oscillations using ytterbiumatoms trapped in an intracavity optical lattice. Demonstration of this technique will pave the waytowards a simple, compact, continuous, and high sensitivity accelerometer. Compared to otheratomic accelerometers which measure a phase, this sensor has the added benefit that it directlyconverts an acceleration into a continuously measurable frequency. This has clear advantagesfor inertial navigation. Light pulse interferometers also suffer from aliasing of vibrationscommensurate with the pulse separation time. The ability to make a continuous measurementwill eliminate this source of technical noise. Finally, the proposed sensor protocol is simple ~laser cooled atoms are loaded into an optical lattice and the output light of the optical cavity iscontinuously recorded.This proposal will extend the PI~s postdoctoral work demonstrating the first optical cavity basedatom interferometer. Traditional atomic fountain interferometers have improved sensitivity byincreasing the duration of free fall, with lengths now up to 10 meters. Further increases presentsevere engineering challenges. Using atoms trapped in an intracavity optical lattice addressesthis in a scalable manner. Even though the effective separation of the interferometer arms is halfan optical wavelength, trapping the atoms allows much longer coherence times. For example thephase difference in an interferometer with ytterbium atoms, trapped and separated by a singlesite in a 532 nm optical lattice, held for T = 5 second, is 40,000 radians. Shot noise limiteddetection of this phase due to gravitational potential energy between lattice sites for 1,000,000atoms gives better than a part per million sensitivity in a single measurement. Coherence timesin optical lattices for over ten seconds have been demonstrated while an equivalent free fallwould require a 500 meter apparatus!While the demonstration in this proposal will utilize an apparatus typical in size for laser coolingexperiments, there is a very clear path towards miniaturization since the actual interferometryregion will be less than a cubic millimeter. An atom chip trap with integrated optical cavityoptics could push the size to cubic centimeter scales. Ultimately one could imagine using highfinesse optical fiber cavities for a truly compact multi-axis sensor.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 05, 2017
- Source ID
- N000141712407
Entities
People
- Paul Hamilton
Organizations
- Office of Naval Research
- United States Navy
- University of California, Los Angeles