Quantum Packaging: Wafer-Level Fabrication of All-Dielectric Vapor Cells for Optically Addressed Rydberg Atom Electrometry
Hunter Shillingburg, Alexandra B. Artusio‐Glimpse, Adil Meraki, G. Lavallee, Miao Liu, Chad M. Eichfeld, Nikunjkumar Prajapati, Matthew T. Simons, Glenn E. Holland, Christopher L. Holloway, Vladimir Aksyuk, Daniel López
We present a technique for fabricating all-glass, microfabricated vapor cells for Rydbergatom electrometry, enabling durable, low-loss millimeter-wave and microwave quantum sensing. This process ensures long-term vacuum stability and robust Rydberg excitation for miniaturized quantum sensors.
Abstract Millimeter-scale atomic vapor cells can be accurately and economically batch-fabricated by anodically bonding silicon and glass wafers, enabling the manufacturing of miniature atomic clocks and quantum sensors. However, silicon’s high dielectric constant and conductive losses at millimeter wave frequencies limit its suitability for Rydberg-atom electrometry, which enables highly sensitive electric-field measurements by exploiting the extreme polarizability of Rydberg states in alkali atoms. To address this, we present an all-glass wafer-level microfabrication process that eliminates silicon, creating hermetically sealed vapor cells that are stable over long timelines with embedded cesium dispensers. Femtosecond laser machining precisely defines the cell geometry, and laser-activated alkali loading ensures reliable filling. We demonstrate long-term vacuum stability and robust Rydberg excitation through electromagnetically induced transparency measurements. We then use these cells to measure a 34 GHz millimeter wave field resonant with the 58D5/2→60P3/2 58 D 5 / 2 → 60 P 3 / 2 transition using Autler-Townes splitting and observe the expected linear dependence with field strength. This work demonstrates that the all-glass bonding approach offers a highly durable low-loss cell alternative for miniaturized millimeter wave and microwave quantum sensing, with the potential to flexibly incorporate a range of other dielectric and semiconductor materials and integrate with photonic and electronic technologies.
Rydberg-atom electrometry, as an emerging cutting-edge technology, features high sensitivity, broad bandwidth, calibration-free operation, and beyond. However, until now the key atomic vapor cells used for confining electric field-sensitive Rydberg atoms nearly made with traditional glass-blown techniques, hindering the miniaturization, integration, and batch manufacturing. Here, we present the wafer-level MEMS atomic vapor cells with glass-silicon-glass sandwiched structure that are batch-manufactured for both frequency stability and electric field measurement. We use specially customized ultra-thick silicon wafers with a resistivity exceeding 10,000 Ω cm, three orders of magnitude higher than that of typical silicon, and a thickness of 6 mm, providing a 4-fold improvement in optical interrogation length. With the as-developed MEMS atomic vapor cell, we configured a high-sensitivity Rydberg-atom electrometry with the minimal detectable microwave field to be 2.8 mV/cm. This combination of miniaturization and sensitivity represents a significant advance in the state-of-the-art field of Rydberg-atom electrometry, paving the way for chip-scale Rydberg-atom electrometry and potentially opening up new applications in a wider variety of fields.
In recent years, micromachined vapor cells have been revolutionizing the field of chip-scale quantum sensors such as magnetometers and atomic clocks. In parallel, Rydberg atomic quantum sensing has emerged as a powerful technique for broadband, non-invasive and ultra-sensitive electrometry. Yet, to date, Rydberg sensing has largely been limited to glass-blown, centimeter-scale vapor cells. Here, we perform Rydberg spectroscopy using a wafer-scale fabricated Pyrex-Si-Pyrex cell with millimeter-scale dimensions. The Rydberg spectroscopic line is characterized with respect to critical parameters such as temperature, the frequency and amplitude of the applied radiofrequency field, light intensity, and the spatial position of the interrogating beam. Our study reveals lineshapes directly influenced by a complex landscape of electrostatic fields with values up to approximately 0.6 V/cm. By controlling key parameters, we were able to reduce the effect of these internal electric fields and demonstrate the detection of RF fields with a sensitivity as low as 10μV/cm These results highlight the potential of micromachined vapor cells for sub-wavelength electromagnetic field measurements, with applications in communications, near-field RF imaging, and chip-scale quantum technologies.
Abstract Micromachined vapor cells have revolutionized chip-scale quantum sensors, including magnetometers and atomic clocks. In parallel, Rydberg-atom quantum sensing has emerged as a powerful platform for broadband, non-invasive and ultra-sensitive electrometry, enabling compact atom-based antenna elements for electromagnetic reception, often referred to as quantum antennas. Yet, to date, Rydberg sensing has largely been limited to glass-blown, cm-scale vapor cells. Here, we perform Rydberg spectroscopy and electrometry using a wafer-scale-fabricated Pyrex–Si–Pyrex cell with millimeter-scale dimensions. The Rydberg spectroscopic line is characterized with respect to critical parameters such as temperature, the frequency and amplitude of the applied radio frequency (RF) field, light intensity, and the spatial position of the interrogating beam. Our study reveals lineshapes directly influenced by a complex landscape of electrostatic fields with values up to approximately 0.6 V cm − 1 . By controlling key parameters, we were able to reduce the effect of these internal electric fields, and demonstrate the detection of RF fields assessed using the Autler–Townes splitting with a minimum detectable field of 20 μ V cm − 1 . Our results highlight the potential of micromachined vapor cells for subwavelength electromagnetic field measurements, with applications in communications, near-field RF imaging, and chip-scale quantum technologies.
Rydberg-atom-based electrometry provides a quantum, SI-traceable approach to radio-frequency (RF) and microwave electric-field sensing by linking optical spectra to absolute field strength through electromagnetically induced trans parency. Over the past decade, rapid advances in excitation schemes, field-tuning methods, interferometric readout, and cavity-assisted coupling have significantly improved sensitivity, bandwidth, and tunability of Rydberg-based sensors. In parallel, progress in fiber-coupled modules, microfabricated vapor cells, and photonic integration is enabling compact and deployable receiver architectures. This review presents a comprehensive and metrology-oriented synthesis of the physical principles, system architectures, standardized performance metrics, and uncertainty considerations relevant to Rydberg-atom RF sensing. By con solidating diverse developments into a unified performance and evaluation framework, this work provides a critical reference for the design, comparison, and advancement of next-generation quantum RF sensors and standards.
We present a comprehensive numerical investigation into the radio frequency (RF) field behavior within miniaturized all-glass and hybrid vapor cell geometries designed for Rydberg atom-based electrometry. Using full-vector finite element modeling (FEM), we analyze electromagnetic field enhancement across a wide frequency range (0.05 GHz to 150 GHz) as a function of polarization, incidence angle, and structural configuration. Two primary vapor cell designs are evaluated: translationally invariant "open" cells and periodically structured "supported" cells composed entirely of low-loss glass, as well as hybrid structures incorporating highly doped silicon. Our simulations reveal that the structured all-glass vapor cells exhibit sharp, angle- and polarization-dependent resonant peaks due to guided-mode coupling, resulting in localized RF power enhancements exceeding 8x. In contrast, silicon-based structures demonstrate significant electric field attenuation and suppression of resonant features due to their high dielectric losses. Through k-vector and angle-resolved analyses, we show how cell geometry and material properties critically influence the RF field distribution and coupling efficiency. Our findings open new possibilities for optimizing vapor cell architectures to enhance field sensitivity, directional and polarization selectivity, and integration potential in chip-scale quantum sensing platforms based on Rydberg atoms.