Chip-Scale Atomic Devices

Abstract

We present an overview of recent work to develop chipscale atomic devices such as frequency references and magnetometers. These devices take advantage of advances over the last ten years in the fields of micro electro mechanical systems (MEMS), precision atomic spectroscopy and semiconductor lasers. The convergence of processes and techniques from these three disparate areas allows for highly compact, low-power sensors with exceptional sensitivity and stability. We will discuss in detail several important ongoing activities in our laboratory including recent advances in alkali cell fabrication and new physics package designs for chip-scale atomic clocks and magnetometers. Finally, we discuss opportunities related to the coupling of resonant, magnetic microstructures to atoms for highly compact, low power sensor applications.

Precision Magnetometers for Aerospace Applications: A Review

“…Atomic magnetometers [ 18 , 130 , 133 , 134 , 135 , 136 , 137 , 138 , 139 ] consist of a vapor of alkali atoms (usually K, Rb, or Cs) enclosed in a glass cell, generally heated to about 400 K. When a laser beam passes through the vapor cell, the spins of the atoms’ unpaired electrons align in the same direction. If a magnetic field is present, the electrons precess, which leads to a polarization or amplitude change in the transmitted light.…”

“…Recent developments in chip-scale atomic magnetometers—such as magnetometers fabricated with silicon micromachining techniques as part of the “NIST on a Chip” program—have demonstrated a significant reduction in SWaP [ 18 ], making them competitive candidates for future CubeSat and UAV projects. The size of these vapor cells is about that of a grain of rice.…”

“…Nevertheless, SERFs are promising candidates for nuclear magnetic resonance sensing [ 141 ]—as might be used to detect extraterrestrial organic compounds in situ—and biomagnetic sensing. They could also be used to perform magnetocardiography or magnetoencephalography on astronauts for non-invasive health monitoring [ 142 , 143 ]; for example, the heart produces a field of approximately 10 pT outside the body, whilst the brain produces fields of around 1 pT at the scalp [ 18 ].…”

“…A particular focus of the review is on emerging magnetometer technologies that use optical readout [ 18 , 19 , 20 ], their performance characteristics, and their potential aerospace applications. This is motivated in part by the exponential growth in the use of unmanned aerial vehicles, together with proposals to use magnetometer-equipped drones for extraplanetary exploration [ 21 , 22 , 23 ].…”

“…This is motivated in part by the exponential growth in the use of unmanned aerial vehicles, together with proposals to use magnetometer-equipped drones for extraplanetary exploration [ 21 , 22 , 23 ]. The optical magnetometers considered in this review include atomic magnetometers (see, e.g., in [ 18 ]), magnetometers based on quantum defects in diamond (see, e.g., in [ 19 ]), and optomechanical magnetometers (see, e.g., in [ 20 ]). While each of these kinds of magnetometer have quite different characteristics, in general, a key attraction has been that they offer exquisite sensitivity without requiring cryogenic cooling.…”