Rabi oscillations with a decay time of 26.7 μs are observed in a system comprising the electron spins in a diamond nitrogen–vacancy centre and a superconducting microwave cavity. Such oscillations are achieved by engineering the spectral hole burning of the spin ensemble. Spectral hole burning, used in inhomogeneously broadened emitters, is a well-established optical1 technique, with applications from spectroscopy to slow light2 and frequency combs3. In microwave photonics4, electron spin ensembles5,6 are candidates for use as quantum memories7 with potentially long storage times8. Here, we demonstrate long-lived collective dark states9 by spectral hole burning in the microwave regime10. The coherence time in our hybrid quantum system (nitrogen–vacancy centres strongly coupled to a superconducting microwave cavity) becomes longer than both the ensemble's free-induction decay and the bare cavity dissipation rate. The hybrid quantum system thus performs better than its individual subcomponents. This opens the way for long-lived quantum multimode memories, solid-state microwave frequency combs, spin squeezed states11, optical-to-microwave quantum transducers12 and novel metamaterials13. Beyond these, new cavity quantum electrodynamics experiments will be possible where spin–spin interactions and many-body phenomena14 are directly accessible.Rabi oscillations with a decay time of 26.7 μs are observed in a system comprising the electron spins in a diamond nitrogen–vacancy centre and a superconducting microwave cavity. Such oscillations are achieved by engineering the spectral hole burning of the spin ensemble. Spectral hole burning, used in inhomogeneously broadened emitters, is a well-established optical1 technique, with applications from spectroscopy to slow light2 and frequency combs3. In microwave photonics4, electron spin ensembles5,6 are candidates for use as quantum memories7 with potentially long storage times8. Here, we demonstrate long-lived collective dark states9 by spectral hole burning in the microwave regime10. The coherence time in our hybrid quantum system (nitrogen–vacancy centres strongly coupled to a superconducting microwave cavity) becomes longer than both the ensemble's free-induction decay and the bare cavity dissipation rate. The hybrid quantum system thus performs better than its individual subcomponents. This opens the way for long-lived quantum multimode memories, solid-state microwave frequency combs, spin squeezed states11, optical-to-microwave quantum transducers12 and novel metamaterials13. Beyond these, new cavity quantum electrodynamics experiments will be possible where spin–spin interactions and many-body phenomena14 are directly accessible.

Bulletin of the American Physical SocietyMar 14, 20171 citation

Photon-gated spectral hole burning in LiGa 5 O 8 :Co 2+

R. M. Macfarlane, J. C. Vial

Photon-gated hole burning, or selective bleaching enabled by a second light source, has been observed in ${\mathrm{Co}}^{2+}$ in tetrahedral sites of ${\mathrm{LiGa}}_{5}$ ${\mathrm{O}}_{8}$ . This leads to long-lived spectral holes with a width of \ensuremath{\sim}1 GHz at 1.6 K. It is proposed that two-step photoionization of ${\mathrm{Co}}^{2+}$ is responsible for the hole burning. Much narrower (\ensuremath{\sim}40 MHz) transient holes and antiholes were burned using population storage in nuclear hyperfine levels. These two mechanisms of hole burning are reported here for transition-metal ions for what is believed to be the first time.Photon-gated hole burning, or selective bleaching enabled by a second light source, has been observed in ${\mathrm{Co}}^{2+}$ in tetrahedral sites of ${\mathrm{LiGa}}_{5}$${\mathrm{O}}_{8}$. This leads to long-lived spectral holes with a width of \ensuremath{\sim}1 GHz at 1.6 K. It is proposed that two-step photoionization of ${\mathrm{Co}}^{2+}$ is responsible for the hole burning. Much narrower (\ensuremath{\sim}40 MHz) transient holes and antiholes were burned using population storage in nuclear hyperfine levels. These two mechanisms of hole burning are reported here for transition-metal ions for what is believed to be the first time.

Jun 9, 19860 citations

Time-resolved spectral hole burning

W. Vogel, D.‐G. Welsch, B. Wilhelmi

Chemical Physics LettersDec 1, 198831 citations

Photon-gated spectral hole burning in LiGa5 O8 : Co2+

R. M. Macfarlane, J. C. Vial

Physical review. B, Condensed matterJul 1, 198647 citations

Persistent Spectral Hole-Burning

W. E. Moerner, Urs P. Wild, Lawrence W. Johnson

Applied OpticsAug 1, 1989157 citations

Photon-gated hole burning, or selective bleaching enabled by a second light source, has been observed in

{\mathrm{Co}}^{2+}

in tetrahedral sites of

{\mathrm{LiGa}}_{5}

{\mathrm{O}}_{8}

. This leads to long-lived spectral holes with a width of \ensuremath{\sim}1 GHz at 1.6 K. It is proposed that two-step photoionization of

{\mathrm{Co}}^{2+}

is responsible for the hole burning. Much narrower (\ensuremath{\sim}40 MHz) transient holes and antiholes were burned using population storage in nuclear hyperfine levels. These two mechanisms of hole burning are reported here for transition-metal ions for what is believed to be the first time.

Photon-gated hole burning, or selective bleaching enabled by a second light source, has been observed in

{\mathrm{Co}}^{2+}

in tetrahedral sites of

{\mathrm{LiGa}}_{5}

{\mathrm{O}}_{8}

. This leads to long-lived spectral holes with a width of \ensuremath{\sim}1 GHz at 1.6 K. It is proposed that two-step photoionization of

{\mathrm{Co}}^{2+}