A Cluster-Based Model of the Spectrum of Erbium-Doped GdVO$_4$

Jevon J. Longdell; Luke S. Trainor; Masaya Hiraishi; Zachary H. Roberts

REVIEW 2 major objections 5 minor 27 references

A Cluster-Based Model of the Spectrum of Erbium-Doped GdVO$_4$

T0 review · 2 major / 5 minor · reviewed 2026-07-14 · grok-4.5

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗ Review JSON

Pith's one-line read A five-ion cluster model reproduces the optical spectrum of Er:GdVO4 across magnetic phases with fewer, more physical parameters.

desk verdict Clean cluster extension of their own earlier model that actually tracks the optical spectrum through AFM, spin-flop and paramagnetic phases with fewer, more physical parameters. read the letter →

arxiv 2607.10924 v1 pith:UCXMGZP7 submitted 2026-07-12 cond-mat.mtrl-sci quant-ph

Zachary H. Roberts , Masaya Hiraishi , Luke S. Trainor , Jevon J. Longdell This is my paper · ORCID

classification cond-mat.mtrl-sciquant-ph

keywords Er:GdVO4clustermodelantiferromagnetrare-earthionsopticalspectrummicrowave-to-opticaltransductionmagnonsspin-flop

verification ladder T0 review T1 audit T2 compute T3 formal

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

Rare-earth ions doped into antiferromagnetic hosts show richer optical spectra than standard crystal-field plus mean-field treatments can explain. This paper builds a cluster model in which each erbium ion couples quantum-mechanically to its four nearest-neighbour gadolinium spins, while those four spins feel the classical mean field of the rest of the lattice. The resulting Hamiltonian uses fewer free parameters than earlier phenomenological models, and the parameters have clear microscopic meanings (exchange couplings I and J, anisotropy D). When the model is fitted to measured transmission spectra it accounts for the observed lines in the antiferromagnetic, spin-flop and paramagnetic phases, including the abrupt spectral collapse past the spin-flop transition. The authors conclude that the same description should reliably locate microwave avoided crossings between erbium and gadolinium excitations, making it a practical tool for predicting microwave-to-optical transduction.

What carries the argument

The five-ion cluster Hamiltonian (Eq. 1 and the subsequent Holstein-Primakoff expansion restricted to the four nearest neighbours). It keeps the local Er-Gd exchange and dipole terms fully quantum while replacing all longer-range Gd-Gd interactions by a classical mean-field configuration obtained from energy minimisation.

What would settle it

Measure the optical spectrum of Er:GdVO4 under a magnetic field applied at a large, precisely known angle to the c-axis and check whether the second doublet still fails to cross near 1 T as the model predicts; a clear avoided crossing at that field would falsify the cluster truncation.

Watch

Extended reading notes

Core claim

A cluster Hamiltonian that treats the erbium ion and its four nearest gadolinium neighbours as a fully quantum five-spin system, while the remaining lattice is replaced by a self-consistent classical mean field, reproduces the measured optical spectrum of Er:GdVO4 from zero field through the spin-flop and into the paramagnetic regime, using fewer and more physically transparent parameters than previous models.

Load-bearing premise

The assumption that only the four nearest gadolinium ions need to be treated as quantum spins, while every other gadolinium ion can be replaced by a static classical mean field.

Share X Bluesky LinkedIn Reddit HN

Signed reviews

No signed human review yet.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Desk Editor's Note

read the letter

This is a solid incremental modelling paper. The real advance is replacing the earlier mean-field-plus-hand-added-oscillator treatment with an explicit five-ion cluster (Er plus four nearest-neighbour Gd) that then couples to a classical mean-field lattice. That construction lets them cover the spin-flop and paramagnetic regimes and off-axis fields with only I and J as magnetic free parameters instead of a handful of empirical effective fields.

What they do well is transparent. The Hamiltonian (free-ion + crystal-field + Zeeman + Heisenberg + dipole + anisotropy) is written out carefully, the Holstein-Primakoff truncation is standard, and the bulk spin configuration is obtained by ordinary energy minimisation. The calculated frequencies track the measured transmission spectra through all three magnetic phases (Figs. 3–4). Crystal-field parameters barely move from their previous fit, and the new J is consistent with the old J_eff once you convert spin magnitudes. That is reassuring.

Soft spots are real but limited. Thirteen spectroscopic parameters are still optimised against the same optical spectrum that is later shown as validation, so the work is not yet predictive. The fourth zero-field line is under-predicted in strength (they correctly note it is probably electric-dipole), and the off-axis self-crossing near 1 T is missed; they flag both. The load-bearing approximation is that only the four nearest Gd ions are dynamical while everything else is classical mean-field. If longer-range quantum correlations matter for the microwave avoided crossings they want to predict, I and J will lose some microscopic meaning. Within the optical data they present, however, the approximation is applied consistently and works.

This is for people already working on rare-earth transducers or magnon–ion hybrids who need a practical Hamiltonian they can actually diagonalise. It is not a foundational breakthrough, but it is careful, reproducible enough (code and data on request), and useful. I would send it to referees without hesitation; the modelling advance is real and the intended application is concrete.

Referee Report

2 major / 5 minor

Summary. The manuscript develops a cluster Hamiltonian for Er:GdVO4 in which the Er ion couples by exchange and dipole–dipole interactions to its four nearest-neighbour Gd spins, which in turn couple to a classical mean-field configuration of the remaining lattice (Eqs. 1–16). Equilibrium sublattice orientations are obtained by classical energy minimisation (Sec. II C), and the resulting spectrum is compared with optical transmission data through the antiferromagnetic, spin-flop and paramagnetic regimes, including modest and large field misalignments (Figs. 3–4). Relative to the authors’ earlier phenomenological model, the fit uses fewer parameters (crystal-field, free-ion, I, J, Ecorr) that have clearer microscopic origins, and the fitted J is shown to be consistent with the previous effective coupling.

Significance. If the optical-level agreement is accepted, the work supplies a more transferable microscopic description of a rare-earth dopant in an antiferromagnetic host than earlier effective-field or oscillator models. The ability to track three magnetic phases and off-axis fields with a single parameter set is a genuine advance for the materials platform. The explicit connection to magnon–erbium avoided crossings, and therefore to microwave-to-optical transduction, is a natural and useful motivation; the paper does not yet deliver those predictions, but the Hamiltonian and fitted exchanges provide a concrete starting point. Code and data availability statements further support reproducibility.

major comments (2)

[Abstract and Sec. IV] Abstract and Sec. IV: the forward-looking claim that the model “may be useful for predicting microwave-to-optical transduction” rests on the microscopic meaning of the fitted I and J. The manuscript validates only the optical spectrum (Figs. 3–4); no microwave-frequency avoided crossings, magnon–Er matrix elements, or zero-field magnon shift are computed. Either add at least one concrete microwave prediction using the reported parameters, or qualify the claim so that optical agreement is not over-read as already establishing transduction utility.
[Sec. II B, Eq. (11)] Sec. II B, Eq. (11) and the Holstein–Primakoff truncation that follows: the cluster approximation (only four nearest-neighbour Gd ions treated as dynamical quantum spins; all others replaced by classical σ0) is load-bearing for the claim that I and J retain microscopic meaning. The paper applies the approximation consistently and obtains a good optical fit, but does not quantify truncation error (e.g., sensitivity to a larger cluster or estimate of longer-range quantum corrections). A short discussion of the expected domain of validity would strengthen the case that the same parameters can be trusted for future microwave calculations.

minor comments (5)

[Sec. II D / Table I] Table I lists thirteen fitted spectroscopic parameters optimised against the same optical spectrum later used for validation. The authors mitigate circularity by showing near-invariance of the crystal-field set and consistency of J with the earlier Jeff (Eq. 19), but a brief statement of the number of independent spectral features versus free parameters would help the reader assess residual freedom.
[Figs. 3–4 and Sec. IV] Fig. 3(b) and Fig. 4(b): the fourth zero-field line is systematically under-predicted in magnetic-dipole strength. The discussion in Sec. IV correctly invokes electric-dipole selection rules, but the figure captions themselves do not flag that the colour scale is MD-only; a one-line note would prevent misreading.
[Fig. 4(a) and Sec. IV] Fig. 4(a): the proposed “absent level” (purple dashed line) is a plausible explanation for the ~1 T self-crossing discrepancy, but remains speculative. Either support it with an additional spectroscopic feature or mark it more clearly as a hypothesis.
[Sec. II B after Eq. (12)] Notation: the factor-of-6I replacement explained after Eq. (12) is easy to miss; a short parenthetical or appendix derivation would improve reproducibility.
[Introduction / Sec. II A / title page] Minor typographical issues: “a a Néel” (Sec. II A); “build this previous model” → “build on” (Introduction); date stamp “2026;01:34” on the title page looks like a compilation artefact.

Circularity Check

2 steps flagged · score 4.0 of 10

Thirteen free parameters (crystal-field, free-ion, I, J, Ecorr) are basinhopped against the optical spectrum of Fig. 3(a); the same spectrum is then presented as the primary evidence that the model 'succeeds in capturing the most important interactions'.

fitted input called prediction [Sec. II D (Fitting) + Abstract + Sec. III (Results) + Sec. IV]
"To fit these parameters we generate transition frequencies for the Z1 o Y1/Y2 transitions, and compare them to the measured spectrum shown in Figure 3(a). … Using the data shown in Figure 3(a), we find the optimum values for our fit parameters. … Agreement with the experimentally observed optical spectrum of Er:GdVO4 suggests that our model succeeds in capturing the most important interactions of the system"

I, J, the five Bq(k), the three Fk, ζ and Ecorr are varied by basinhopping until the calculated transition frequencies match the line positions of Fig. 3(a). The subsequent claim that the model 'agrees' with that spectrum and therefore 'captures the most important interactions' is therefore true by construction of the fit rather than by an independent prediction. The same fitted Hamiltonian is then used to generate the panels of Fig. 3(b,c) that are offered as validation.
self citation load bearing [Sec. I + Sec. IV (comparison to prior model)]
"In our previous work [9], we modelled the Er:GdVO4 system by placing the erbium ion in a crystal field environment, as well as a static mean field … Comparison of the fitted parameters we find in Table I to those in Table S1 of Ref. [9] shows that our new fitted crystal field parameters only vary by 2 cm-1 at most. … This is very close to the fitted value of J=-0.0252 cm-1 that we find for the cluster model."

The experimental spectrum being fitted, the earlier phenomenological parameters used as the starting point for basinhopping, and the consistency check that legitimises the new J all rest on the authors' own prior paper [9]. While the new cluster Hamiltonian is an independent construction, the quantitative claim that the new parameters are 'consistent' and therefore more physical relies on a self-citation that is not externally verified within the present work.

full rationale

The Hamiltonian construction itself (cluster of four nearest-neighbour Gd spins + classical mean-field remainder, Holstein-Primakoff truncation, dipole + exchange terms) is independent of the optical data and is not circular. The circularity is confined to the validation step: the parameters that control the fine structure of the Z1 o Y1/Y2 manifold are optimised by minimising residuals to the very spectrum later shown in Fig. 3 and invoked in the abstract and Discussion as proof that the model works. Consistency checks with the earlier J_eff of Ref. [9] and with the known HA field mitigate but do not remove the fact that the optical line positions remain both the fitting target and the principal claimed success. Extension to the off-axis data of Fig. 4 and to the spin-flop/paramagnetic regimes supplies modest independent content, so the circularity is only partial (score 4). No self-definitional loop, uniqueness theorem, or ansatz smuggling is present.

Assumptions & free parameters 5 free parameters · 4 assumptions · 0 invented entities

The central claim rests on a standard crystal-field plus Heisenberg-plus-dipole Hamiltonian whose free parameters are fitted to the optical spectrum, together with the cluster/mean-field approximation that truncates the many-body problem. No new particles or forces are invented; the free parameters are conventional spectroscopic quantities plus two exchange constants.

free parameters (5)

Crystal-field parameters B0_2, B0_4, B0_6, B4_4, B4_6 = see Table I
Fitted by basinhopping to the measured optical spectrum; values change by at most 2 cm^{-1} from the authors’ previous work.
Free-ion parameters E0, F2, F4, F6, ζ = see Table I
Adjusted from LaF3 starting values to improve the optical fit; Ecorr is an additional ad-hoc offset of the 4I13/2 manifold.
Gd–Gd exchange I = -0.0475 cm^{-1}
Treated as free rather than fixed by the literature exchange field HE; used both to set the mean-field and to compute HE via Eq. 6.
Er–Gd exchange J = -0.0252 cm^{-1}
Primary coupling constant of the cluster; fitted to the optical spectrum and later compared with a rescaled earlier J_eff.
Field misalignment angle θ = 6.8° / 60°
Fixed at 6.8° for the main data set (from prior work) but freely chosen as 60° for the large-misalignment data set to match line separations.

assumptions (4)

ad hoc to paper Only the four nearest-neighbour Gd ions are treated as dynamical quantum spins; all other Gd ions are replaced by a classical mean-field configuration σ0 obtained by energy minimisation.
Introduced in Sec. II B as ‘the cluster approximation’; load-bearing for the entire spectrum calculation.
domain assumption Spin operators are truncated at quadratic order in Holstein–Primakoff deviation operators and projected onto the two lowest Sz levels of each Gd ion.
Standard low-temperature magnon approximation (Rezende Ch. 5.3); invoked after Eq. 10.
domain assumption Electric-dipole transition strengths cannot be calculated from the model and are ignored; only magnetic-dipole matrix elements are used to estimate relative intensities.
Stated in Sec. II E; explains the under-predicted fourth line but is accepted as a modelling limitation.
domain assumption The bulk spin configuration is obtained by classical energy minimisation of a two-sublattice Heisenberg–anisotropy Hamiltonian (Eq. 17).
Standard mean-field treatment of GdVO4; used to generate the three magnetic phases shown in Fig. 2.

how reviews work

0 comments

Cite this review

Pith. "Pith review of A Cluster-Based Model of the Spectrum of Erbium-Doped GdVO$_4$." pith.science (2026). https://pith.science/paper/UCXMGZP7

@misc{pith2026260710924,
  author       = {Pith},
  title        = {Pith review of: A Cluster-Based Model of the Spectrum of Erbium-Doped GdVO$_4$},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/UCXMGZP7}},
  note         = {Machine review of arXiv:2607.10924}
}

abstract

Experimental observations of rare-earth ions doped into an antiferromagnetic crystal show an enriched optical spectrum. In this paper we present a cluster-based model to describe erbium ions doped into a gadolinium vanadate (Er:GdVO$_4$) host crystal, wherein the erbium ion couples directly to its four nearest neighbour gadolinium ions, which in turn couple to the mean field of the rest of the crystal. Compared to previous models in the literature, the parameters used to fit this model are fewer in number, with clearer physical origins. Agreement with the experimentally observed optical spectrum of Er:GdVO$_4$ suggests that our model succeeds in capturing the most important interactions of the system, suggesting that it may be useful for predicting microwave-to-optical transduction in future experiments.

Figures

Figures reproduced from arXiv: 2607.10924 by the authors.

**Figure 2.** FIG. 2. The three different spin configuration phases our antiferromagnetic system can exhibit. The black arrows depict the [PITH_FULL_IMAGE:figures/full_fig_p005_2.png] view at source ↗

**Figure 3.** FIG. 3. (a) Optical transmission spectrum with light polarised halfway between the [PITH_FULL_IMAGE:figures/full_fig_p006_3.png] view at source ↗

Figures from the paper (1 more)

**Figure 4.** Figure 4: FIG. 4. (a) Optical transmission spectrum with light polarised halfway between the [PITH_FULL_IMAGE:figures/full_fig_p007_4.png]

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

27 extracted references

[1]

Ranˇ ci´ c, M

M. Ranˇ ci´ c, M. P. Hedges, R. L. Ahlefeldt, and M. J. Sellars, Coherence time of over a second in a telecom- compatible quantum memory storage material, Nature Physics14, 50 (2018)

2018
[2]

B¨ ottger, C

T. B¨ ottger, C. W. Thiel, R. L. Cone, and Y. Sun, Effects of magnetic field orientation on optical decoherence in Er3+:Y2SiO5, Phys. Rev. B79, 115104 (2009)

2009
[3]

Awschalom, K

D. Awschalom, K. K. Berggren, H. Bernien, S. Bhave, L. D. Carr, P. Davids, S. E. Economou, D. Englund, A. Faraon, M. Fejer, S. Guha, M. V. Gustafsson, E. Hu, L. Jiang, J. Kim, B. Korzh, P. Kumar, P. G. Kwiat, M. Lonˇ car, M. D. Lukin, D. A. B. Miller, C. Monroe, 8 S. W. Nam, P. Narang, J. S. Orcutt, M. G. Raymer, A. H. Safavi-Naeini, M. Spiropulu, K. Srin...

2021
[4]

J. R. Everts, M. C. Berrington, R. L. Ahlefeldt, and J. J. Longdell, Microwave to optical photon conversion via fully concentrated rare-earth-ion crystals, Physical Review A99, 063830 (2019)

2019
[5]

O’Brien, N

C. O’Brien, N. Lauk, S. Blum, G. Morigi, and M. Fleis- chhauer, Interfacing superconducting qubits and telecom photons via a rare-earth-doped crystal, Physical Review Letters113, 063603 (2014)

2014
[6]

Fernandez-Gonzalvo, S

X. Fernandez-Gonzalvo, S. P. Horvath, Y.-H. Chen, and J. J. Longdell, Cavity-enhanced raman heterodyne spec- troscopy in er 3+ : y2sio5 for microwave to optical signal conversion, Phys. Rev. A100, 033807 (2019)

2019
[7]

T. Xie, R. Fukumori, J. Li, and A. Faraon, Scalable microwave-to-optical transducers at single photon level with spins, Nature Physics , 931 (2025)

2025
[8]

Zhong, M

M. Zhong, M. P. Hedges, R. L. Ahlefeldt, J. G. Bartholomew, S. E. Beavan, S. M. Wittig, J. J. Longdell, and M. J. Sellars, Optically addressable nuclear spins in a solid with a six-hour coherence time, Nature517, 177 (2015)

2015

Show all 27 references

[9]

Hiraishi, Z

M. Hiraishi, Z. H. Roberts, G. G. G. King, L. S. Trainor, and J. J. Longdell, Long optical coherence times in a rare- earth-doped antiferromagnet, Nature Physics21, 1112 (2025)

2025
[10]

M. M. Abraham, J. M. Baker, B. Bleaney, J. Z. Pfeffer, and M. R. Wells, Antiferromagnetic resonance in GdVO4, Journal of Physics: Condensed Matter4, 5443 (1992)

1992
[11]

N. J. Lambert, A. Rueda, F. Sedlmeir, and H. G. L. Schwefel, Coherent conversion between microwave and optical photons—an overview of physical implemen- tations, Advanced Quantum Technologies3, 1900077 (2020)

2020
[12]

Bleaney, Electron spin resonance of paramag- netic impurities in antiferromagnetic compounds, Pro- ceedings of the Royal Society of London

B. Bleaney, Electron spin resonance of paramag- netic impurities in antiferromagnetic compounds, Pro- ceedings of the Royal Society of London. Series A: Mathematical and Physical Sciences433, 461 (1991), https://royalsocietypublishing.org/rspa/article- pdf/433/1888/461/68055/r...

1991
[13]

M. M. Abraham, J. M. Baker, B. Bleaney, A. A. Jenkins, P. M. Martineau, and J. Z. Pfeffer, Mag- netic resonance of lanthanide ions as magnetic probes in the antiferromagnetic phase of dysprosium phos- phate, Proceedings of the Royal Society of London. Se- ries A: Mathematical ...

1991
[14]

Bleaney, A

B. Bleaney, A. C. de Oliveira, and M. R. Wells, Nu- clear magnetic resonance of 51V (I=7/2) in lanthanide vanadates: Iii. the antiferromagnetic phases of gdvo4 and dyvo4, Journal of Physics C: Solid State Physics15, 5305 (1982)

1982
[15]

M. C. Berrington,Optical studies of magnetically ordered erbium crystals, Ph.D. thesis, Australian National Uni- versity (2022)

2022
[16]

R. A. COWLEY and W. J. L. BUYERS, The properties of defects in magnetic insulators, Rev. Mod. Phys.44, 406 (1972)

1972
[17]

W. O. Milligan and L. W. Vernon, Crystal structure of heavy metal orthovanadates, The Journal of Physical Chemistry56, 145 (1952)

1952
[18]

J. D. Cashion, A. H. Cooke, L. A. Hoel, D. M. Mar- tin, and M. R. Wells, Magnetic properties of gadolin- ium ortho-vanadate, in ´Elements des terres rares, Vol. 2, Centre National de la Recherche Scientifique (Paris) (´Editions du Centre National de la Recherche Scien- tifique...

1970
[19]

Bertini, A

C. Bertini, A. Toncelli, M. Tonelli, E. Cavalli, and N. Magnani, Optical spectroscopy and laser parame- ters of GdVO 4:Er3+, Journal of Luminescence106, 235 (2004)

2004
[20]

S. M. Rezende,Fundamentals of Magnonics, Lecture Notes in Physics (Springer, 2020)

2020
[21]

W. T. Carnall, G. L. Goodman, K. Rajnak, and R. S. Rana, A systematic analysis of the spectra of the lan- thanides doped into single crystal LaF 3, The Journal of Chemical Physics90, 3443 (1989)

1989
[22]

B. G. Wybourne and L. Smentek,Optical Spectroscopy of Lanthanides(CRC Press, 2007)

2007
[23]

Duan and M

C.-K. Duan and M. F. Reid, Local field effects on the radiative lifetimes of ce3+ in different hosts, Current Ap- plied Physics6, 348 (2006), aMN-2 (Second International Conference on Advanced Materials and Nanotechnology)

2006
[24]

M. C. Berrington, M. J. Sellars, J. J. Longdell, H. M. Rønnow, H. H. Vallabhapurapu, C. Adambukulam, A. Laucht, and R. L. Ahlefeldt, Negative Refractive Index in Dielectric Crystals Containing Stoichiometric Rare- Earth Ions, Advanced Optical Materials11, 2301167 (2023)

2023
[25]

Marino, I

R. Marino, I. Lorger´ e, O. Guillot-No¨ el, H. Vezin, A. Ton- celli, M. Tonelli, J.-L. Le Gou¨ et, and P. Goldner, En- ergy level structure and optical dephasing under mag- netic field in Er 3+:LiYF4 at 1.5µm, Journal of Lumi- nescence The 17th International Conference on Lumi...

2016
[26]

G. T. Rado and H. Suhl, Magnetism (Academic Press, New York, 1963) Chap. 2

1963
[27]

https://github.com/jevonlongdell/dieke

Pith tools

Reviewed July 14, 2026 · model on record in the stance chip above.

[1] [1]

Ranˇ ci´ c, M

M. Ranˇ ci´ c, M. P. Hedges, R. L. Ahlefeldt, and M. J. Sellars, Coherence time of over a second in a telecom- compatible quantum memory storage material, Nature Physics14, 50 (2018)

2018

[2] [2]

B¨ ottger, C

T. B¨ ottger, C. W. Thiel, R. L. Cone, and Y. Sun, Effects of magnetic field orientation on optical decoherence in Er3+:Y2SiO5, Phys. Rev. B79, 115104 (2009)

2009

[3] [3]

Awschalom, K

D. Awschalom, K. K. Berggren, H. Bernien, S. Bhave, L. D. Carr, P. Davids, S. E. Economou, D. Englund, A. Faraon, M. Fejer, S. Guha, M. V. Gustafsson, E. Hu, L. Jiang, J. Kim, B. Korzh, P. Kumar, P. G. Kwiat, M. Lonˇ car, M. D. Lukin, D. A. B. Miller, C. Monroe, 8 S. W. Nam, P. Narang, J. S. Orcutt, M. G. Raymer, A. H. Safavi-Naeini, M. Spiropulu, K. Srin...

2021

[4] [4]

J. R. Everts, M. C. Berrington, R. L. Ahlefeldt, and J. J. Longdell, Microwave to optical photon conversion via fully concentrated rare-earth-ion crystals, Physical Review A99, 063830 (2019)

2019

[5] [5]

O’Brien, N

C. O’Brien, N. Lauk, S. Blum, G. Morigi, and M. Fleis- chhauer, Interfacing superconducting qubits and telecom photons via a rare-earth-doped crystal, Physical Review Letters113, 063603 (2014)

2014

[6] [6]

Fernandez-Gonzalvo, S

X. Fernandez-Gonzalvo, S. P. Horvath, Y.-H. Chen, and J. J. Longdell, Cavity-enhanced raman heterodyne spec- troscopy in er 3+ : y2sio5 for microwave to optical signal conversion, Phys. Rev. A100, 033807 (2019)

2019

[7] [7]

T. Xie, R. Fukumori, J. Li, and A. Faraon, Scalable microwave-to-optical transducers at single photon level with spins, Nature Physics , 931 (2025)

2025

[8] [8]

Zhong, M

M. Zhong, M. P. Hedges, R. L. Ahlefeldt, J. G. Bartholomew, S. E. Beavan, S. M. Wittig, J. J. Longdell, and M. J. Sellars, Optically addressable nuclear spins in a solid with a six-hour coherence time, Nature517, 177 (2015)

2015