Zhong, M. et al. Optically addressable nuclear spins in a solid with a six-hour coherence time. Nature 517, 177–180 (2015).
Rančić, M., Hedges, M. P., Ahlefeldt, R. L. & Sellars, M. J. Coherence time of over a second in a telecom-compatible quantum memory storage material. Nat. Phys. 14, 50–54 (2018).
Ortu, A. et al. Simultaneous coherence enhancement of optical and microwave transitions in solid-state electronic spins. Nat. Mater. 17, 671–675 (2018).
Böttger, T., Thiel, C. W., Cone, R. L. & Sun, Y. Effects of magnetic field orientation on optical decoherence in Er3+:Y2SiO5. Phys. Rev. B 79, 115104 (2009).
Equall, R. W., Sun, Y., Cone, R. L. & Macfarlane, R. M. Ultraslow optical dephasing in Eu3+:Y2SiO5. Phys. Rev. Lett. 72, 2179–2182 (1994).
Le Dantec, M. et al. Twenty-three–millisecond electron spin coherence of erbium ions in a natural-abundance crystal. Sci. Adv. 7, eabj9786 (2021).
Sun, Y., Thiel, C. W., Cone, R. L., Equall, R. W. & Hutcheson, R. L. Recent progress in developing new rare earth materials for hole burning and coherent transient applications. J. Lumin. 98, 281–287 (2002).
Fraval, E., Sellars, M. J. & Longdell, J. J. Method of extending hyperfine coherence times in Pr3+:Y2SiO5. Phys. Rev. Lett. 92, 077601 (2004).
Wolfowicz, G. et al. Atomic clock transitions in silicon-based spin qubits. Nat. Nanotechnol. 8, 561–564 (2013).
Mohammady, M. H., Morley, G. W. & Monteiro, T. S. Bismuth qubits in silicon: the role of EPR cancellation resonances. Phys. Rev. Lett. 105, 067602 (2010).
Ahlefeldt, R. L., Manson, N. B. & Sellars, M. J. Optical lifetime and linewidth studies of the 7F0 → 5D0 transition in EuCl3 ⋅ 6H2O: a potential material for quantum memory applications. J. Lumin. 133, 152–156 (2013).
Berrington, M. C. et al. Negative refractive index in dielectric crystals containing stoichiometric rare-earth ions. Adv. Opt. Mater. 11, 2301167 (2023).
Everts, J. R. et al. Ultrastrong coupling between a microwave resonator and antiferromagnetic resonances of rare-earth ion spins. Phys. Rev. B 101, 214414 (2020).
Awschalom, D. et al. Development of quantum interconnects for next-generation information technologies. PRX Quantum 2, 017002 (2021).
Lambert, N. J., Rueda, A., Sedlmeir, F. & Schwefel, H. G. L. Coherent conversion between microwave and optical photons—an overview of physical implementations. Adv. Quantum Technol. 3, 1900077 (2020).
Wang, C.-H., Li, F. & Jiang, L. Quantum capacities of transducers. Nat. Commun. 13, 6698 (2022).
Higginbotham, A. P. et al. Harnessing electro-optic correlations in an efficient mechanical converter. Nat. Phys. 14, 1038–1042 (2018).
Jiang, W. et al. Efficient bidirectional piezo-optomechanical transduction between microwave and optical frequency. Nat. Commun. 11, 1166 (2020).
Zhong, C. et al. Heralded generation and detection of entangled microwave–optical photon pairs. Phys. Rev. Lett. 124, 010511 (2020).
Fan, L. et al. Superconducting cavity electro-optics: a platform for coherent photon conversion between superconducting and photonic circuits. Sci. Adv. 4, eaar4994 (2018).
Rueda, A. et al. Efficient microwave to optical photon conversion: an electro-optical realization. Optica 3, 597–604 (2016).
Tu, H.-T. et al. High-efficiency coherent microwave-to-optics conversion via off-resonant scattering. Nat. Photonics 16, 291–296 (2022).
Vogt, T. et al. Efficient microwave-to-optical conversion using Rydberg atoms. Phys. Rev. A 99, 023832 (2019).
Hisatomi, R. et al. Bidirectional conversion between microwave and light via ferromagnetic magnons. Phys. Rev. B 93, 174427 (2016).
Zhu, N. et al. Waveguide cavity optomagnonics for microwave-to-optics conversion. Optica 7, 1291–1297 (2020).
Everts, J. R., Berrington, M. C., Ahlefeldt, R. L. & Longdell, J. J. Microwave to optical photon conversion via fully concentrated rare-earth-ion crystals. Phys. Rev. A 99, 063830 (2019).
Xie, T., Fukumori, R., Li, J. & Faraon, A. Scalable microwave-to-optical transducers at the single-photon level with spins. Nat. Phys. https://doi.org/10.1038/s41567-025-02884-y (2025).
Puel, T. O., et al.) PC126561E (SPIE, 2023).
Puel, T. O., Turflinger, A. T., Horvath, S. P., Thompson, J. & Flatté, M. E. Enhancement of microwave to optical spin-based quantum transduction via a magnon mode. In Proc. Quantum Computing, Communication, and Simulation IV, Vol. PC12911 (eds Hemmer, P. R. & Migdall, A. L.) PC129110H (SPIE, 2024).
Puel, T. O., Turflinger, A. T., Horvath, S. P., Thompson, J. D. & Flatté, M. E. Enhancement of microwave to optical spin-based quantum transduction via a magnon mode. Preprint at arxiv.org/abs/2411.12870 (2024).
Milligan, W. O. & Vernon, L. W. Crystal structure of heavy metal orthovanadates. J. Phys. Chem. 56, 145–147 (1952).
Cashion, J. D., Cooke, A. H., Hoel, L. A., Martin, D. M. & Wells, M. R. Proc. International Symposium on Rare Earths (Centre National de la Recherche Scientifique, 1970).
Xie, T. et al. Characterization of Er3+:YVO4 for microwave to optical transduction. Phys. Rev. B 104, 054111 (2021).
Li, P.-Y. et al. Optical spectroscopy and coherent dynamics of 167Er3+:YVO4 at 1.5 μm below 1 K. J. Lumin. 225, 117344 (2020).
Page, J. H. & Rosenberg, H. M. Ultrasonic attenuation in GdVO4 at 9 GHz. J. Phys. C. 10, 353–367 (1977).
Bertini, C., Toncelli, A., Tonelli, M., Cavalli, E. & Magnani, N. Optical spectroscopy and laser parameters of GdVO4:Er3+. J. Lumin. 106, 235–242 (2004).
Laplane, C., Zambrini Cruzeiro, E., Fröwis, F., Goldner, P. & Afzelius, M. High-precision measurement of the Dzyaloshinsky-Moriya interaction between two rare-earth ions in a solid. Phys. Rev. Lett. 117, 037203 (2016).
Jongerden, G. J., Kil, A. J., Dijkhuis, J. I., Arts, A. F. & De Wijn, H. W. Optical generation of magnons by direct spin-magnon relaxation in MnF2: Er3+. J. Phys. Colloq. 46, C7-241–C7-245 (1985).
Abraham, M. M., Baker, J. M., Bleaney, B., Pfeffer, J. Z. & Wells, M. R. Antiferromagnetic resonance in GdVO4. J. Phys. Condens. Matter 4, 5443–5446 (1992).
Kanai, S. et al. Generalized scaling of spin qubit coherence in over 12,000 host materials. Proc. Natl Acad. Sci. USA 119, e2121808119 (2022).
Singh, M. K. et al. Epitaxial Er-doped Y2O3 on silicon for quantum coherent devices. APL Mater. 8, 031111 (2020).
Bartholomew, J. G. et al. On-chip coherent microwave-to-optical transduction mediated by ytterbium in YVO4. Nat. Commun. 11, 3266 (2020).
O’Brien, C., Lauk, N., Blum, S., Morigi, G. & Fleischhauer, M. Interfacing superconducting qubits and telecom photons via a rare-earth-doped crystal. Phys. Rev. Lett. 113, 063603 (2014).
Williamson, L. A., Chen, Y.-H. & Longdell, J. J. Magneto-optic modulator with unit quantum efficiency. Phys. Rev. Lett. 113, 203601 (2014).
Welinski, S. et al. Electron spin coherence in optically excited states of rare-earth ions for microwave to optical quantum transducers. Phys. Rev. Lett. 122, 247401 (2019).
King, G. G. G., Barnett, P. S., Bartholomew, J. G., Faraon, A. & Longdell, J. J. Probing strong coupling between a microwave cavity and a spin ensemble with Raman heterodyne spectroscopy. Phys. Rev. B 103, 214305 (2021).
Fernandez-Gonzalvo, X., Horvath, S. P., Chen, Y.-H. & Longdell, J. J. Cavity-enhanced Raman heterodyne spectroscopy in Er3+:Y2SiO5 for microwave to optical signal conversion. Phys. Rev. A 100, 033807 (2019).
DeVoe, R. G., Szabo, A., Rand, S. C. & Brewer, R. G. Ultraslow optical dephasing of LaF3:Pr3+. Phys. Rev. Lett. 42, 1560–1563 (1979).
Rezende, S. M., Azevedo, A. & Rodríguez-Suárez, R. L. Introduction to antiferromagnetic magnons. J. Appl. Phys. 126, 151101 (2019).
Longdell, J. J. Dieke: crystal field calculation for rare earths. GitHub https://github.com/jevonlongdell/dieke (2024).