Andrei Tretiakov | Searcharxiv

arXiv2026

Hyperfine spectroscopy of optical-cycling transitions in singly ionized thulium

We present a spectroscopic investigation of $^{169}\mathrm{Tm}^+$ that provides two key foundations for its use as a platform for advanced quantum applications. First, we establish the complete spectroscopic road map for optical cycling (including laser cooling) by performing high-resolution spectroscopy on $^{169}\mathrm{Tm}^+$ ions in an ion trap. We characterize the primary $313\,\mathrm{nm}$ and complementary $448/453\,\mathrm{nm}$ cycling transitions, identify the essential near-infrared repumping frequencies, and determine the magnetic-dipole hyperfine $A$ constants for all relevant levels. Second, we report a detailed characterization of a metastable state as a candidate for hosting a robust qubit, performing lifetime measurements and Zeeman-resolved microwave hyperfine spectroscopy with $\mathrm{kHz}$ precision.

physics.atom-ph↗

arXiv2025

Microwave-optical double-resonance vector magnetometry with warm Rb atoms

Developing a non-invasive, accurate vector magnetometer that operates at ambient temperature and is conducive to miniaturization and is self-calibrating is a significant challenge. Here, we present an unshielded three-axis vector magnetometer whose operation is based on the angle-dependent relative amplitude of magneto-optical double-resonance features in a room-temperature atomic ensemble. Magnetic-field-dependent double resonance features change the transmission of an optical probe tuned to the D2 optical transition of $^{87}$Rb in the presence of a microwave field driving population between the Zeeman sublevels of the ground state hyperfine levels $F = 1$ and $F = 2$. Sweeping the microwave frequency over all Zeeman sublevels results in seven double-resonance features, whose amplitudes vary as the orientation of the external static magnetic field changes with respect to the optical and microwave field polarization directions. Using a convolutional neural network model, the magnetic field direction is measured in this proof-of-concept experiment with an accuracy of 1° and its amplitude near 50 $μ$T with an accuracy of 115 nT.

physics.atom-ph↗