In the present work, ultrafast photon echo spectroscopy has been applied to investigate dephasing dynamics and excited state electronic structure of impurity N-V centers in diamond and Tm$\sp{3+}$-Tm$\sp{3+}$ centers. In the N-V center, quantum beat measurements revealed modulation frequencies of 0.63 $\pm$ 0.02 GHz, 1.650 $\pm$ 0.003 GHz, and 2.298 $\pm$ 0.006 GHz which furnished excited state spin-spin splittings directly for the first time. Wavelength dependent studies of dephasing times showed conclusively the existence of a larger splitting of 46 $\pm$ 2 cm$\sp{-1}$ in the excited E state. These results were found to be consistent with temperature dependent studies which reveal dephasing, near liquid-He temperatures, is dominated by a one-phonon direct dephasing process in the upper state with an activation energy of 68 $\pm$ 16 cm$\sp{-1}$ has a two-phonon Orbach contribution to dephasing in the lower state with an activation energy of 39 $\pm$ 5 cm$\sp{-1}.$ Experiments with circularly polarized light also revealed an interesting polarization selection rule originating from Zeeman coherence in the doublet E spin state of the $\sp3A$ ground state. A complete multi-electron model is presented which makes use of a previously undetected Jahn-Teller effect to explain all the observed excited state structure. An extension of these ultrafast techniques were applied to Tm$\sp{3+}$-Tm$\sp{3+}$ centers in YAlO$\sb3,$ permitting the first preliminary investigations of coherent dynamics on highly cooperative transitions. Dephasing times on the $\sp3F\sb4(\Gamma\sp2)$ $\to$ $\sp1G\sb4(\Gamma\sp1)$ excited state transitions were found to increase from 35 $\pm$ 2 ps to 61 $\pm$ 6 ps with decreasing intensity of a resonant auxiliary cw laser which populates this transition in a controllable fashion. Temperature dependence studies revealed dephasing on this cooperative transition was dominated by a direct process with an activation energy of 157 $\pm$ 16 cm$\sp{-1}$ at liquid-He temperatures. These results were consistent with expected dephasing rate dependence for interacting Tm$\sp{3+}$-Tm$\sp{3+}$ centers.In the present work, ultrafast photon echo spectroscopy has been applied to investigate dephasing dynamics and excited state electronic structure of impurity N-V centers in diamond and Tm$\sp{3+}$-Tm$\sp{3+}$ centers. In the N-V center, quantum beat measurements revealed modulation frequencies of 0.63 $\pm$ 0.02 GHz, 1.650 $\pm$ 0.003 GHz, and 2.298 $\pm$ 0.006 GHz which furnished excited state spin-spin splittings directly for the first time. Wavelength dependent studies of dephasing times showed conclusively the existence of a larger splitting of 46 $\pm$ 2 cm$\sp{-1}$ in the excited E state. These results were found to be consistent with temperature dependent studies which reveal dephasing, near liquid-He temperatures, is dominated by a one-phonon direct dephasing process in the upper state with an activation energy of 68 $\pm$ 16 cm$\sp{-1}$ has a two-phonon Orbach contribution to dephasing in the lower state with an activation energy of 39 $\pm$ 5 cm$\sp{-1}.$ Experiments with circularly polarized light also revealed an interesting polarization selection rule originating from Zeeman coherence in the doublet E spin state of the $\sp3A$ ground state. A complete multi-electron model is presented which makes use of a previously undetected Jahn-Teller effect to explain all the observed excited state structure. An extension of these ultrafast techniques were applied to Tm$\sp{3+}$-Tm$\sp{3+}$ centers in YAlO$\sb3,$ permitting the first preliminary investigations of coherent dynamics on highly cooperative transitions. Dephasing times on the $\sp3F\sb4(\Gamma\sp2)$ $\to$ $\sp1G\sb4(\Gamma\sp1)$ excited state transitions were found to increase from 35 $\pm$ 2 ps to 61 $\pm$ 6 ps with decreasing intensity of a resonant auxiliary cw laser which populates this transition in a controllable fashion. Temperature dependence studies revealed dephasing on this cooperative transition was dominated by a direct process with an activation energy of 157 $\pm$ 16 cm$\sp{-1}$ at liquid-He temperatures. These results were consistent with expected dephasing rate dependence for interacting Tm$\sp{3+}$-Tm$\sp{3+}$ centers.

Jan 1, 19930 citations

Spin bath mediated long-lived coherent oscillations of NV centers in diamond

Akshat Rana, Pooja Lamba, Basanta Mistri +3 more

Decoherence is the biggest bottleneck in all quantum technologies. For nitrogen-vacancy (NV) centers in diamond, the loss of coherence is caused by the electron and nuclear spin bath of the diamond lattice. Here, we demonstrate that the spin bath - that typically causes decoherence - entangles the spin states of the NV electron and the host $^{14}$ N nucleus. The many-body interaction between the $^{14}$ N nucleus - electron - bath spins at an energy level anti-crossing occurring for an applied magnetic field orientation perpendicular to the NV axis is responsible for this effect. This is observed experimentally in NV ensembles via electron spin-echo measurements, where the echo envelope is modulated at the frequency of a $^{14}$ N nuclear spin transition. Using numerical simulations, we show that the spin bath coupling to the NV centers is essential for observing this modulation. Due to the zero first-order Zeeman effect at the anti-crossing, the observed oscillations have long spin-echo coherence times, 2--3 times those at the parallel magnetic field orientation. The oscillation frequency is highly stable and robust against environmental fluctuations. These findings provide new opportunities for fundamental studies of many-body physics and quantum sensing.Decoherence is the biggest bottleneck in all quantum technologies. For nitrogen-vacancy (NV) centers in diamond, the loss of coherence is caused by the electron and nuclear spin bath of the diamond lattice. Here, we demonstrate that the spin bath - that typically causes decoherence - entangles the spin states of the NV electron and the host $^{14}$N nucleus. The many-body interaction between the $^{14}$N nucleus - electron - bath spins at an energy level anti-crossing occurring for an applied magnetic field orientation perpendicular to the NV axis is responsible for this effect. This is observed experimentally in NV ensembles via electron spin-echo measurements, where the echo envelope is modulated at the frequency of a $^{14}$N nuclear spin transition. Using numerical simulations, we show that the spin bath coupling to the NV centers is essential for observing this modulation. Due to the zero first-order Zeeman effect at the anti-crossing, the observed oscillations have long spin-echo coherence times, 2--3 times those at the parallel magnetic field orientation. The oscillation frequency is highly stable and robust against environmental fluctuations. These findings provide new opportunities for fundamental studies of many-body physics and quantum sensing.

quant-pharXiv:2606.30146Jun 30, 20260 citations

Double quantum coherence control in NV- centers in Diamond at small fields

Osama Moussa, Ian Hincks, David G. Cory

Bulletin of the American Physical SocietyJun 7, 20130 citations

\pm

0.02 GHz, 1.650

\pm

0.003 GHz, and 2.298

\pm

0.006 GHz which furnished excited state spin-spin splittings directly for the first time. Wavelength dependent studies of dephasing times showed conclusively the existence of a larger splitting of 46

\pm

2 cm$\sp{-1}$ in the excited E state. These results were found to be consistent with temperature dependent studies which reveal dephasing, near liquid-He temperatures, is dominated by a one-phonon direct dephasing process in the upper state with an activation energy of 68

\pm

16 cm$\sp{-1}$ has a two-phonon Orbach contribution to dephasing in the lower state with an activation energy of 39

\pm

5 cm$\sp{-1}.$ Experiments with circularly polarized light also revealed an interesting polarization selection rule originating from Zeeman coherence in the doublet E spin state of the $\sp3A$ ground state. A complete multi-electron model is presented which makes use of a previously undetected Jahn-Teller effect to explain all the observed excited state structure. An extension of these ultrafast techniques were applied to Tm$\sp{3+}$-Tm$\sp{3+}$ centers in YAlO$\sb3,$ permitting the first preliminary investigations of coherent dynamics on highly cooperative transitions. Dephasing times on the $\sp3F\sb4(\Gamma\sp2)$

\to

$\sp1G\sb4(\Gamma\sp1)$ excited state transitions were found to increase from 35

\pm

2 ps to 61

\pm

6 ps with decreasing intensity of a resonant auxiliary cw laser which populates this transition in a controllable fashion. Temperature dependence studies revealed dephasing on this cooperative transition was dominated by a direct process with an activation energy of 157

\pm

16 cm$\sp{-1}$ at liquid-He temperatures. These results were consistent with expected dephasing rate dependence for interacting Tm$\sp{3+}$-Tm$\sp{3+}$ centers.

^{14}

N nucleus. The many-body interaction between the

^{14}

N nucleus - electron - bath spins at an energy level anti-crossing occurring for an applied magnetic field orientation perpendicular to the NV axis is responsible for this effect. This is observed experimentally in NV ensembles via electron spin-echo measurements, where the echo envelope is modulated at the frequency of a

^{14}

N nuclear spin transition. Using numerical simulations, we show that the spin bath coupling to the NV centers is essential for observing this modulation. Due to the zero first-order Zeeman effect at the anti-crossing, the observed oscillations have long spin-echo coherence times, 2--3 times those at the parallel magnetic field orientation. The oscillation frequency is highly stable and robust against environmental fluctuations. These findings provide new opportunities for fundamental studies of many-body physics and quantum sensing.