Non-contact optical magnetic field sensor based on metamaterial nanomechanics

Abstract

We demonstrate a non-contact optical magnetic field sensor that is based on actuation of a metamaterial-microcavity by the magnetic Lorentz force. Magnetic field is transduced to a change of the sensor’s reflectivity. The microscale proof-of-concept metamaterial magnetometer can be read from a distance and offers 60 μm spatial, about 10 μs temporal, and sub-microtesla magnetic field resolution.

Optimization of metamaterials and metamaterial-microcavity based on deep neural networks

“…The external force can modulate this distance, thus changing the optical response of the microcavity. In particular, magnetic field sensor which use Lorentz force to change the distance of the gap is an important application field of this kind of metamaterial-microcavity 30 . Next, we expect this sensor to be able to transmit signals over long distances by optical fiber for non-contact and harsh environment applications.…”

“…Theoretical analysis and experimental results show that the metamaterial-microcavity composed of a single-layer metamaterial and an optical mirror can greatly improve the optical response characteristics. 29,30 In this case, its overall optical reflectance will be determined by the reflection and transmission coefficients of the single-layer metamaterial as well as the gap of the microcavity, and can be described theoretically as follows: 29 where r and t are the complex Fresnel reflection and transmission coefficients of the single-layer metamaterial, m is the reflection coefficient of the mirror, α = 2π d / λ is the phase change and d is the distance of the gap. The external force can modulate this distance, thus changing the optical response of the microcavity.…”

“…Theoretical analysis and experimental results show that the metamaterial-microcavity composed of a single-layer metamaterial and an optical mirror can greatly improve the optical response characteristics. 29,30 In this case, its overall optical reectance will be determined by the reection and transmission coefficients of the single-layer metamaterial as well as the gap of the microcavity, and can be described theoretically as follows: 29…”

“…If we want to provide functionalities on demand for flexible applications of metamaterials, temporal or space modulation of metamaterial-based devices are needed. Several methods such as adding a mirror to consist of a Fabry-Pérot microcavity to modulate optical response by nanomechanics or using light to actuate individual metamaterial elements on demand with different mechanical resonance have been proposed 30,31 . The optimal design of such metamaterial structures remains challenging.…”

“…Several methods such as adding a mirror to accommodate a Fabry-Pérot microcavity to modulate optical response by nanomechanics or using light to actuate individual metamaterial elements on demand with different mechanical resonances have been proposed. 30,31 The optimal design of such metamaterial structures remains challenging.…”