Optically detected nuclear quadrupolar interaction ofN14in nitrogen-vacancy centers in diamond

Abstract

We report sensitive detection of the nuclear quadrupolar interaction of the 14 N nuclear spin of the nitrogenvacancy (NV) center using the electron spin-echo envelope modulation technique. We applied a weak transverse magnetic field to the spin system so that certain forbidden transitions became weakly allowed due to second-order effects involving the nonsecular terms of the hyperfine interaction. The weak transitions cause modulation of the electron spin-echo signal, and a theoretical analysis suggests that the modulation frequency is primarily determined by the nuclear quadrupolar frequency; numerical simulations confirm the analytical results and show excellent quantitative agreement with experiments. This is an experimentally simple method of detecting quadrupolar interactions, and it can be used to study spin systems with an energy structure similar to that of the NV center.

Double-Quantum Spin-Relaxation Limits to Coherence of Near-Surface Nitrogen-Vacancy Centers

“…In the presence of a weak transverse magnetic field compared to D gs and B z = 0 (θ = 90 • ) the eigenstates are approximately [35,86]…”

Modulation depth enhancement of ESEEM experiments using pulse trains

“…Surprisingly, the echo modulations due to the weakly coupled nuclei were significantly enhanced with the number of applied pulses, N . Although the CPMG sequence is a well-established NMR method [17,18] and has been recently used in EPR spectroscopy either as a dynamical decoupling method [19,20,21] or as a detection scheme to increase the signal-to-noise ratio in pulse EPR experiments [22,23], to date its relation to the ESEEM effect has been reported in some cases [24,25] but a systematic analysis is still lacking. Herein we analyze our previous observation by extending our study to a two-dimensional (2D) method where the repeated part of the sequence is based on the refocusing primary echo method [4].…”

Measurement of transverse hyperfine interaction by forbidden transitions

“…While the secular part of the NV-14 N Hamiltonian has been well-characterized before [22][23][24] , the transverse hyperfine coupling is more difficult to measure 25 and published values do not match well [26][27][28] . The most precise characterization to date has been achieved by ensemble ESR techniques 27 .…”