arXiv subjects

E. Klinger

Publications and source records attributed to E. Klinger.

7 recordsLinked to original sources

arXiv2025

Microfabricated multi-axis cell for integrated atomic devices

Microfabricated alkali vapor cells enable the miniaturization of atomic sensors, but require collective wafer-level integration of complex features. In many applications, including magnetometers, gyroscopes, magneto-optical traps, and fluorescence imaging, multiple optical accesses are needed to enhance performance. Yet, achieving this without compromising manufacturability remains challenging. In this work, we present a wafer-level fabrication approach that enables three orthogonal optical pathways in microfabricated alkali vapor cells, using fully scalable and collective processes. Our method relies on the thermal reflow of glass preforms, shaped by laser-assisted etching (LAE) and bonded between silicon frames. The relatively low surface roughness produced by LAE allows effective reflow, which further smooths the surfaces without significantly compromising the optical planarity of the windows. This process results in multi-axis vapor cells featuring embedded, optics-grade lateral windows. We evaluate the device performance through both single-beam and dual-beam atomic magnetometry measurements. Magnetic sensitivities better than 200 fT/sqrt(Hz) are demonstrated along each of the three orthogonal axes, confirming the potential of the approach for tri-axis magnetic field sensing at sub-picotesla resolution. This fabrication strategy opens new perspectives for versatile, high-performance atomic sensors, fully compatible with wafer-level integration and mass production.

physics.atom-ph↗

arXiv2025

Doppler-free spectroscopy of the Cs $6\text{S}_{1/2}-7\text{P}_{3/2}$ atomic transition at 456 nm in a nanometric-thick vapor layer

The features of Doppler-free resonances detected by probing the $^{133}$Cs atom $6S_{1/2}-7P_{3/2}$ transition at 456 nm in a nanometric-thick vapor layer are investigated. The matrix element of this transition is about 11 times smaller than that of the Cs D$_2$ line (852 nm). When the vapor layer thickness is $\ell = \lambda/2 \simeq 230$ nm, we observe Dicke narrowing of the lines, accompanied by a red frequency shift of the atomic transitions, which is attributed to atom-surface interactions. Realizing optical pumping with $\ell\simeq 460$ nm in a single-pass configuration, we observe Doppler-free resonances with a linewidth $<20$ MHz, located at the atomic transitions frequencies with a correspondence of the amplitudes to the transition intensities. These narrow resonances are of interest for high-resolution spectroscopy and instrumentation, and could serve as a frequency reference.

physics.atom-ph↗

arXiv2025

Cs microcell optical reference at 459 nm with short-term frequency stability below 2 $\times$ 10$^{-13}$

We describe the short-term frequency stability characterization of external-cavity diode lasers stabilized onto the 6S$_{1/2}$-7P$_{1/2}$ transition of Cs atom at 459 nm, using a microfabricated vapor cell. The laser beatnote between two nearly-identical systems, each using saturated absorption spectroscopy in a simple retroreflected configuration, exhibits an instability of $2.5\times10^{-13}$ at 1 s, consistent with phase noise analysis, and $3\times 10^{-14}$ at 200 s. The primary contributors to the stability budget at one second are the FM-AM noise conversion and the intermodulation effect, both emerging from laser frequency noise. These results highlight the potential of microcell-based optical references to achieve stability performances comparable to that of an active hydrogen maser in a remarkably simple architecture.

physics.atom-ph↗

arXiv2024

A Multi-Messenger Search for Exotic Field Emission with a Global Magnetometer Network

Quantum sensor networks in combination with traditional astronomical observations are emerging as a novel modality for multi-messenger astronomy. Here we develop a generic analysis framework that uses a data-driven approach to model the sensitivity of a quantum sensor network to astrophysical signals as a consequence of beyond-the-Standard Model (BSM) physics. The analysis method evaluates correlations between sensors to search for BSM signals coincident with astrophysical triggers such as black hole mergers, supernovae, or fast radio bursts. Complementary to astroparticle approaches that search for particlelike signals (e.g. WIMPs), quantum sensors are sensitive to wavelike signals from exotic quantum fields. This analysis method can be applied to networks of different types of quantum sensors, such as atomic clocks, matter-wave interferometers, and nuclear clocks, which can probe many types of interactions between BSM fields and standard model particles. We use this analysis method to carry out the first direct search utilizing a terrestrial network of precision quantum sensors for BSM fields emitted during a black hole merger. Specifically we use the Global Network of Optical Magnetometers for Exotic physics (GNOME) to perform a search for exotic low-mass field (ELF) bursts generated in coincidence with a gravitational wave signal from a binary black hole merger (GW200311 115853) detected by LIGO/Virgo on the 11th of March 2020. The associated gravitational wave heralds the arrival of the ELF burst that interacts with the spins of fermions in the magnetometers. This enables GNOME to serve as a tool for multi-messenger astronomy. Our search found no significant events, and consequently we place the first lab-based limits on combinations of ELF production and coupling parameters.

astro-ph.HE↗

arXiv2024

Features of alkali D$_2$ line magnetically-induced transitions excited under {\pi}-polarized laser radiation

The impact of the optical field polarization on the spectrum of magnetically-induced transitions, a class of transitions forbidden at zero magnetic field, is studied with a weak-probe sub-Doppler technique. The high spectral resolution of the technique combined with the simplicity in interpreting the observed spectra, allows to follow the behavior of individual transitions as a function of the magnetic field amplitude. We observe only one intense transition (out of $2F_g+1$, where F is the quantum number associated with the total angular momentum of the atom) in the case of linear ($\pi$) polarization (a configuration where the applied magnetic field is parallel to the electric field from the laser radiation) in the $F_g\rightarrow F_g+2$ manifolds of $^{85}$Rb, $^{87}$Rb and $^{133}$Cs for fields above a few hundreds of gauss. We show that this behavior is in agreement with a model based on the diagonalization of the Zeeman Hamiltonian matrix. With the rapid development of micro-machined vapor-cell-based sensors these results will be of use to magnetometers operating above Earth field, wide-range laser frequency stabilization systems and atomic Faraday filters.

physics.atom-ph↗

arXiv2023

What can a GNOME do? Search targets for the Global Network of Optical Magnetometers for Exotic physics searches

Numerous observations suggest that there exist undiscovered beyond-the-Standard-Model particles and fields. Because of their unknown nature, these exotic particles and fields could interact with Standard Model particles in many different ways and assume a variety of possible configurations. Here we present an overview of the Global Network of Optical Magnetometers for Exotic physics searches (GNOME), our ongoing experimental program designed to test a wide range of exotic physics scenarios. The GNOME experiment utilizes a worldwide network of shielded atomic magnetometers (and, more recently, comagnetometers) to search for spatially and temporally correlated signals due to torques on atomic spins from exotic fields of astrophysical origin. We survey the temporal characteristics of a variety of possible signals currently under investigation such as those from topological defect dark matter (axion-like particle domain walls), axion-like particle stars, solitons of complex-valued scalar fields (Q-balls), stochastic fluctuations of bosonic dark matter fields, a solar axion-like particle halo, and bursts of ultralight bosonic fields produced by cataclysmic astrophysical events such as binary black hole mergers.

hep-ph↗

arXiv2017

Symmetry breaking exhibition by magnetic field induced explicit circular dichroism

In this letter we demonstrate universal symmetry breaking by means of magnetically induced circular dichroism. Magnetic field induces forbidden at zero field atomic transitions between $\Delta F = \pm2$ hyperfine levels. In a particular range of magnetic field, intensities of these transitions experience significant enhancement. We have deduced a general rule applicable for the $D_2$ lines of all bosonic alkali atoms, that is transition intensity enhancement is larger for the case of $\sigma^+$ than for $\sigma^-$ excitation for $\Delta F = +2$, whereas it is larger (e.g. up to $10^{11}$ times for $^{85}$Rb atoms) in the case of $\sigma^-$ than for $\sigma^+$ polarization for $\Delta F = -2$. This asymmetric behaviour results in an explicit circular dichroism. For experimental verification we employed half-wavelength-thick atomic vapor nanocells using a derivative of selective reflection technique, which provides sub-Doppler spectroscopic linewidth ($\sim$50 MHz). The presented theoretical curves well describe the experimental results. This effect can find applications particularly in parity violation experiments.

physics.atom-ph↗