The interaction between light and vapors in the presence of magnetic fields is fundamental to many quantum technologies and applications. Recently, the ability to geometrically confine atoms into periodic structures has enabled the creation of chip-scale, micromachined hybrid atomic-diffractive optical elements. However, applying magnetic fields to such structures remains largely unexplored, offering potential for both fundamental and applied insights. Here, we present measurements of an atomic-diffractive optical element subject to magnetic fields. In contrast to the well-known polarization rotation in a Faraday medium, these diffractive atomic elements exhibit additional, rapidly oscillating rotation terms, which we validate both theoretically and experimentally. Moreover, we find that the introduction of spatially varying magnetic fields leads to a reduction in fringe visibility, which can be leveraged for gradiometric applications. Together, these effects establish a chip-scale platform where diffraction and quantum sensing are inseparably co-engineered, unveiling previously inaccessible regimes of atom–photon–magnetic interaction. By probing the magneto-optic response of periodically confined vapors, our results lay the groundwork for integrated smart-cell magnetometers and open new avenues for flat-optics-enabled quantum photonic devices.
The interaction between light and vapors in the presence of magnetic fields is fundamental to many quantum technologies and applications. Recently, the ability to geometrically confine atoms into periodic structures has enabled the creation of chip-scale, micromachined hybrid atomic-diffractive optical elements. However, applying magnetic fields to such structures remains largely unexplored, offering potential for both fundamental and applied insights. Here, we present measurements of an atomic-diffractive optical element subject to magnetic fields. In contrast to the well-known polarization rotation in a Faraday medium, these diffractive atomic elements exhibit additional, rapidly oscillating rotation terms, which we validate both theoretically and experimentally. Moreover, we find that the introduction of spatially varying magnetic fields leads to a reduction in fringe visibility, which can be leveraged for gradiometric applications. Together, these effects establish a chip-scale platform where diffraction and quantum sensing are inseparably co-engineered, unveiling previously inaccessible regimes of atom–photon–magnetic interaction. By probing the magneto-optic response of periodically confined vapors, our results lay the groundwork for integrated smart-cell magnetometers and open new avenues for flat-optics-enabled quantum photonic devices.
The efficient light-matter interaction and discrete level structure of atomic vapors made possible numerous seminal scientific achievements including time-keeping, extreme non-linear interactions, and strong coupling to electric and magnetic fields in quantum sensors. As such, atomic systems can be regarded as a highly resourceful quantum material platform. Recently, the field of thin optical elements with miniscule features has been extensively studied demonstrating an unprecedented ability to control photonic degrees of freedom. Hybridization of atoms with such thin optical devices may offer a material system enhancing the functionality of traditional vapor cells. Here, we demonstrate chip-scale, quantum diffractive optical elements which map atomic states to the spatial distribution of diffracted light. Two foundational diffractive elements, lamellar gratings and Fresnel lenses, are hybridized with atomic vapors demonstrating exceptionally strong frequency-dependent, non-linear and magneto-optic behaviors. Providing the design tools for chip-scale atomic diffractive optical elements develops a path for compact thin quantum-optical elements.
This paper reports the development and characterization of an atomic magnetometer with a microfabricatedRb atomic vapour cell as the sensing element. The measurement principle is based on the Faraday rotation of linearly polarized probe light, which interacts resonantly with atomic spin states in the presence of a magnetic field. In the chip-scale vapour cell (dimensions: 8.0 mm × 12.0 mm × 1.5 mm), the atomic vapour is confined to a micromachined optical cavity of 3.5 µL with an optical path length of 0.5 mm. Optical interrogation is performed using a single laser beam tuned to the D1 absorption resonance of ⁸⁵Rb. The rotation arises due to magnetically induced circular birefringence in the hot atomic vapour. A bench model of the magnetometer is demonstrated over a measurement range of ±50 µT with a maximum uncertainty of 800 nT in an unshielded environment. The magneto-optic rotation (MOR) response in the laboratory was investigated and is observed to vary from 5×10³ rad/T for near zero magnetic field to 3.2×10³ rad/T for ambient geomagnetic field.
Abstract Optical magnetometers based on alkali vapors, such as rubidium, are among the most sensitive technologies for detecting and characterizing magnetic fields. Following the recent effort in miniaturizing atomic-based quantum technologies, the last years were marked by a growing interest in developing integrated quantum nanophotonic circuits for a vast range of applications. Motivated by the attractiveness of such chip-scale integration, we present and experimentally demonstrate an integrated magnetic sensing platform, based on a nanophotonic-chip interfaced to a microfabricated alkali vapor cell. Magnetically induced circular dichroism in rubidium vapor is measured using a planar structure that spatially resolves the handedness of incoming photons depending on their spin. The presented approach paves the way toward further integration of highly sensitive magnetometers, with potential for future applications, such as in high-spatial resolution magnetic vectorial imaging.
Offset stabilization of a laser's frequency relative to an atomic transition is crucial for many quantum technologies, but equipment for it is often bulky or dependent on magnetic fields, limiting integration into compact systems. Exploiting the interference properties of atoms geometrically confined within diffractive optical elements, this study presents a chip-scale, hybrid atomic-photonic approach that enables multiple stabilization points with submegahertz precision over a bandwidth of tens of gigahertz. This miniaturization, with no need for magnetic fields, points to the next generation of compact laser-stabilization devices for quantum applications and precision spectroscopy.
Recently, there has been growing interest in the miniaturization and integration of atomic-based quantum technologies. In addition to the obvious advantages brought by such integration in facilitating mass production, reducing the footprint, and reducing the cost, the flexibility offered by on-chip integration enables the development of new concepts and capabilities. In particular, recent advanced techniques based on computer-assisted optimization algorithms enable the development of newly engineered photonic structures with unconventional functionalities. Taking this concept further, we hereby demonstrate the design, fabrication, and experimental characterization of an integrated nanophotonic-atomic chip magnetometer based on alkali vapor with a micrometer-scale spatial resolution and a magnetic sensitivity of 700 pT/√Hz. The presented platform paves the way for future applications using integrated photonic-atomic chips, including high-spatial-resolution magnetometry, near-field vectorial imaging, magnetically induced switching, and optical isolation.
Quantum sensing is an ever-evolving research field describing the use of a quantum phenomenon to perform measurement of a physical quantity. Amongst different types of quantum sensors, atomic vapor-based quantum effects are extensively used to measure quantities such as time, velocity, acceleration, electric, and magnetic fields. Here, we propose and demonstrate remote quantum sensing using a chip-scale atomic vapor cell. Specifically, we remotely interrogate millimeter-scale micromachined vapor cells, and measure the ambient Earth’s magnetic field at a standoff distance of ∼10 m and a sensitivity of ∼1 pT/√Hz. We further spatially map different magnetic fields in the presence of a noisy ambient environment. Simultaneously we are able measure the distance between a micro-cell and the interrogating system by means of time-of-flight measurements, thus correlating between position and magnetic field. Utilizing micromachined vapor cells for remote magnetometry offers substantial advantages in scalability, planar photonic integration, cost, and size. Consequently, we provide a novel toolset to deploy, measure, and map arbitrary, remote, and hard-to-access magnetic fields in unshielded environments with high sensitivity and spatial resolution, paving the way to a variety of novel applications in diverse fields such as medicine, communication, defense, space-exploration, and quantum technologies.