Magnetic shield integration for a chip-scale atomic clock

Abstract

We introduce a miniaturized magnetic shield integrated into the physics package of a chip-scale atomic clock. The primary shield, which is formed by a stack of precision-machined high-permeability plates, compactly sits inside the package as it is designed to be the internal supporting frame. Further improved by a Kovar lid, the best frequency sensitivity to a longitudinal external field is 1.1(3) × 10−11/μT, which is consistent with the measured shielding factor, while the transverse sensitivity is well below 10−12/μT. The sealed unit on a chip carrier alone allows stable clock operation with a frequency instability of 4.8(2) × 10−12 at 1000 s.

Chip-Scale Ultra-Low Field Atomic Magnetometer Based on Coherent Population Trapping

“…Our chip-scale magnetometer package is basically identical to the one we used for a compact CPT clock [ 28 ]. The core spectroscopy unit is comprised of a vertical cavity surface emission laser (VCSEL), a quarter wave plate (QWP), a micro-fabricated cesium vapor cell, and a photodiode all aligned vertically ( Figure 2 ).…”

“…The board distributes signals to off-the-shelf instruments for measurement and control ( Figure 3 d). We employ a compact magnetic shield, which allows us easy characterization of the package [ 28 ]. Although imperfect, it could be used, after nulling, for providing a zero-field environment due to small field-inhomogeneity as revealed in the linewidths of CPT spectra for high ’s.…”

“…The nulling condition is determined by measuring Zeeman shift for various bias coil currents. In particular, the center of the quadratic Zeeman shift corresponds to the offset field [ 28 ], which amounts to 3.02 μT in this case. The zero-field environment is provided by nulling the residual field by the bias coil.…”

Design of a multi-laser module for optical pumping in compact atomic gyroscopes

“…15 For atomic magnetometers or atomic clocks, only the alkali metal atoms need to be polarized, thus few hundreds of µW pump power is usually enough. [20][21][22] However, when there are noble gas atoms which require to be hyper-polarized, many research indicated that 1 mW pump power is generally not sufficient. [23][24][25][26] This causes great challenges to the development of compact atomic gyroscopes.…”

On‐Chip Light–Atom Interactions: Physics and Applications

“…There are various applications of on chip light–atom interactions, such as chip‐scale magnetometer, [ 1–3 ] frequency reference, [ 4 ] atomic clock, [ 5–8 ] quantum logic gate, [ 9–11 ] single‐photon switch, [ 12 ] and quantum repeater, [ 13–15 ] realized by local field enhancement and light modulation. For example, an on‐chip atomic magnetometer using special nanostructures has attained a magnetic field measurement precision of , which has tremendous scope for futher improvement while the interaction volume is only .…”