Coherent spin dynamics of ytterbium ions in yttrium orthosilicate

Abstract

We investigate the electron and nuclear spin coherence properties of ytterbium (Yb 3+ ) ions with non-zero nuclear spin, within an yttrium orthosilicate (Y2SiO5) crystal, with a view to their potential application in quantum memories or repeaters. We find electron spin-lattice relaxation times are maximised at low magnetic field (< 100 mT) where g ∼ 6, reaching 5 s at 2.5 K, while coherence times are maximised when addressing ESR transitions at higher fields where g ∼ 0.7 where a Hahn echo measurement yields T2 up to 73 µs. Dynamical decoupling (XY16) can be used to suppress spectral diffusion and extend the coherence lifetime to over 0.5 ms, close to the limit of instantaneous diffusion. Using Davies electron-nuclear-double-resonance (ENDOR), we performed coherent control of the 173 Yb 3+ nuclear spin and studied its relaxation dynamics. At around 4.5 K we measure a nuclear spin T1 and T2 of 4 and 0.35 ms, respectively, about 4 and 14 times longer than the corresponding times for the electron spin. arXiv:1712.00435v1 [quant-ph] 1 Dec 2017

Coherence Time Extension by Large-Scale Optical Spin Polarization in a Rare-Earth Doped Crystal

“…Since flip-flop interactions do not change the overall level populations, the recovery rate R c , obtained by an exponential fit to the data, corresponds to the SLR rate. This result is confirmed by the R c temperature dependence, which can be well modeled by a sum of a direct process and two-phonon processes, with parameters consistent with previous studies at higher magnetic field [33], as detailed in the Supplemental Material [38]…”

“…We next investigate optical coherence lifetimes T 2;o under DEOP. This investigation was motivated by several studies that have shown that flipping ground-state spins of paramagnetic RE can be a major source of magnetic noise and therefore cause dephasing to RE optical and spin transitions [8,33]. This dephasing can be reduced by inducing strong spin polarization under large magnetic field and/or ultralow temperatures, by broadband optical pumping, or by using excited-state spins [13,14,30,42,43].…”

“…These materials, in which optical and spin coherence lifetime can reach up to ms and hours at low temperatures [6,12,21], are actively investigated for spin-based quantum photonic applications ranging from quantum memories [2,[22][23][24][25], processors [26], and single-photon sources [27,28] to optical-microwave transducers [29,30]. Note that 171 Yb 3þ ∶YSO, in which long coherence lifetimes have been shown for both optical and spin transitions at zero magnetic field [18], is particularly promising in these areas [31][32][33][34]. Using DEOP, we obtain spin polarizations greater than 90%, a much stronger effect than previously reported in ruby [35] and in Refs.…”

Storage and retrieval of microwave pulses with molecular spin ensembles

“…2e) to the intrinsic spin dynamics of the sample. We might also argue that the different efficiency of CP and DD sequences is due to the fact they address different spectral portions of the environmental noise distribution 36,38,42 . However, a more detailed analysis of this latter point would require a dedicated work.…”

“…These protocols are widely used to dynamically decouple the spins from environmental sources of decoherence and, hence, are expected to enhance T m [36][37][38][39] . Although the efficiency of CP and DD sequences has been previously investigated on spin impurities in inorganic matrices [40][41][42] and in organic molecules [43][44][45] (including radicals 39,46 ) coupled to conventional (3-dimensional) ESR cavities, their efficiency still needs to be tested on molecular spins in working conditions 1,21 . Here we report, for the first time to the best of our knowledge, an extensive study concerning the PW manipulation of molecular spins embedded into planar resonators.…”