Sonderseminar: High-resolution spectroscopy of individual nuclear spins using microwave photon counting

  • date:

    Mittwoch 10.09.2025, 14.00 Uhr

  • speaker:

    Patrice Bertet
    Centre CEA Paris-Saclay/ DRF/Institut IRAMIS/SPEC, Quantronics Group, Universität PARIS-SACLAY, Frankreich

  • Abstract: We have developed a novel Electron Paramagnetic Resonance (EPR) detection method at millikelvin temperatures [1]. It is based on the energy relaxation of paramagnetic centers by spontaneous emission of a microwave photon at their Larmor frequency, enhanced by resonant coupling to a superconducting resonator with a micron- or sub-micron-scale constriction [2]. The spins in the vicinity of the constriction are excited by a π pulse, and the photons subsequently emitted are detected by a specially designed microwave photon counter based on a superconducting qubit [3]. Thanks to the high sensitivity of the counter, the method can reach single spin sensitivity, as recently demonstrated with individual Er3+ ions in a scheelite crystal of CaWO4 [4].
    We then use an individual Er3+ spin as a nano-antenna to dynamically polarize and meas- ure the spectrum of individual nuclear spins of 183W in the vicinity [5], as well as a spin-9/2 93Nb impurity. We achieve Hertz spectral resolution, enabling to detect minute effects such as an electron-spin-dependent quadrupole interaction, as well as Larmor frequency shifts that we interpret as being due to the different chemical environment of each 183W spin.

     

    [1] E. Albertinale et al., Nature, 2021, 600, 434
    [2] A. Bienfait et al., Nature, 2016, 531, 74
    [3] R. Lescanne et al., Physical Review X, 2020, 10, 021038
    [4] Z. Wang et al., Nature, 2023, 619, 276
    [5] J Travesedo et al., Science Advances 11 (10), eadu0581