Room temperature "Optical Nanodiamond Hyperpolarizer": physics, design and operation

Ajoy, Ashok; Nazaryan, Raffi; Druga, Emanuel; Liu, Kristina; Aguilar, Alessandra; Han, Bo; Gierth, Max; Oon, Jner Tzern; Safvati, Ben; Tsang, Ryan; Walton, Jeffrey H.; Suter, Dieter; Meriles, Carlos A.; Reimer, Jeffrey A.; Pines, Alexander

doi:10.48550/arxiv.1811.10218

Cited by 3 publications

(9 citation statements)

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“…We refer the reader to a detailed exposition in Refs. [17,18], but sketch the apparatus here for completeness. Generating bulk polarization in the diamond powders relies continuous laser pumping at low-fields, and subsequent sample transfer to high field (7T) magnet for NMR inductive readout.…”

Section: Experimental Apparatusmentioning

confidence: 99%

“…The 13 C nuclear magnetic resonance (NMR) signal can often be enhanced by several orders of magnitude, in a manner completely independent of particle orientation, with the hyperpolarization being carried out at room temperature and with relatively benign resources. Indeed, such optical methods for dynamic nuclear polarization (DNP) [14,15] present several advantages over conventional methods involving cryogenic temperatures and large magnetic fields [16], since the hyperpolarization can be generated replenishably and under am- * ashokaj@berkeley.edu bient conditions and with modest resources (low optical and microwave powers) [17,18]. As a representative example, Fig.…”

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confidence: 99%

“…Acknowledgments Methods: -Hyperpolarization at room temperature is carried out by nine fiber-coupled 520 nm laser diodes (Lasertack) at a 38mT polarizing field generated by a pair of Helmholtz coils. A self shorted split-solenoid coaxial line connected to a 16W MW amplifier provides the microwave excitation that initially consists of frequency chirps generated from three cascaded voltage controlled oscillator (VCO) sources driven by a home-built quad ramp voltage generator [18]. The diamond particles are immersed in water to leverage scattering-induced uniform illumination, as well as for heat sinking.…”

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confidence: 99%

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High temperature annealing enhanced diamond 13C hyperpolarization at room temperature

Gierth,

Krespach,

Shames

et al. 2019

Preprint

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Methods of optical dynamic nuclear polarization (DNP) open the door to the replenishable hyperpolarization of nuclear spins, boosting their NMR/MRI signature by orders of magnitude. Nanodiamond powder rich in negatively charged Nitrogen Vacancy (NV -) defect centers has recently emerged as one such promising platform, wherein 13 C nuclei can be hyperpolarized through the optically pumped defects completely at room temperature and at low magnetic fields. Given the compelling possibility of relaying this 13 C polarization to nuclei in external liquids, there is an urgent need for the engineered production of highly "hyperpolarizable" diamond particles. In this paper, we report on a systematic study of various material dimensions affecting optical 13 C hyperpolarization in diamond particles -especially electron irradiation and annealing conditions that drive NVcenter formation. We discover surprisingly that diamond annealing at elevated temperatures close to 1720 • C have remarkable effects on the hyperpolarization levels, enhancing them by upto 36-fold over materials annealed through conventional means. We unravel the intriguing material origins of these gains, and demonstrate they arise from a simultaneous improvement in NVelectron relaxation time and coherence time, as well as the reduction of paramagnetic content, and an increase in 13 C relaxation lifetimes. Overall this points to significant recovery of the diamond lattice from radiation damage as a result of the high-temperature annealing. Our work suggests methods for the guided materials production of fluorescent, 13 C hyperpolarized, nanodiamonds and pathways for their use as multi-modal (optical and MRI) imaging and hyperpolarization agents.

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Section: Experimental Apparatusmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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High temperature annealing enhanced diamond 13C hyperpolarization at room temperature

Gierth,

Krespach,

Shames

et al. 2019

Preprint

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“…It is worth noting that hyperpolarization through our method requires relatively low laser (∼2mW/mg) and MW power (∼0.05mW/mg), where the estimates are reported for equivalent mass-weighted SNR to images presented here. Considering the saturation regime for a single 1µm diamond particle, we estimate a 30nW optical and 2nW MW power requirement respectively [19]. Due to the high mass of the particles here, our MRI experimental demonstrations were performed with laser power densities ∼80mW/mm 2 , somewhat elevated above levels suitable for in-vivo operation (∼4.7mW/mm 2 [20]); indeed, laser power is not restrictive in preclinical settings since substantially lower masses are typically employed [21].…”

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confidence: 99%

“…For in-vitro samples, the use of higher laser power close to saturation intensity (∼1W/mm 3 ) can increase the MR signal 10 times compared with the present results. Diamonds with higher 13 C content will provide larger signals, with the resulting SNR improvement scaling with enrichment [19]. Further improvements may be realized by optimizing the detection coil geometry and increasing of filling factor, for instance through the use of small volume inductively-coupled receiver coils [27,28] matched to the sample under study.…”

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confidence: 99%

High contrast dual-mode optical and 13C magnetic resonance imaging in diamond particles

Lv,

Walton,

Druga

et al. 2019

Preprint

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Multichannel imaging -the ability to acquire images of an object through more than one imaging mode simultaneously -has opened exciting new avenues in several areas from astronomy to biomedicine. Visible optics and magnetic resonance imaging (MRI) offer complimentary advantages of resolution, speed and depth of penetration, and as such would be attractive in combination. In this paper, we take first steps towards marrying together optical and MR imaging in a class of biocompatible and deployable particulate materials constructed out of diamond. The particles are endowed with a high density of quantum defects (Nitrogen Vacancy centers) that under optical excitation fluoresce brightly in the visible, but also concurrently electron spin polarize, allowing the hyperpolarization of lattice 13 C nuclei to make the particles over three-orders of magnitude brighter than in conventional MRI. We highlight additional benefits in background-free imaging, demonstrating lock-in suppression by factors of 2 and 5 in optical and MR domains respectively, although ultimate limits are at least two orders of magnitude in each domain. Finally, leveraging the ability of optical and MR imaging to simultaneously probe Fourier-reciprocal domains (real and k-space), we elucidate the ability to employ hybrid sub-sampling in both conjugate spaces to vastly accelerate dual-image acquisition, by as much as two orders of magnitude in practically relevant sparse-imaging scenarios. Our work portends new avenues for quantum-enhanced dualmode imaging platforms and opens possibilities for new therapeutic avenues including in low-field MRI-guided endoscopy.

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Hyperpolarized relaxometry based nuclear T1 noise spectroscopy in diamond

et al. 2019

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Understanding the origins of spin lifetimes in hybrid quantum systems is a matter of current importance in several areas of quantum information and sensing. Methods that spectrally map spin relaxation processes provide insight into their origin and can motivate methods to mitigate them. In this paper, using a combination of hyperpolarization and precision field cycling over a wide range (1mT-7T), we map frequency dependent relaxation in a prototypical hybrid system of 13 C nuclear spins in diamond coupled to Nitrogen Vacancy centers. Nuclear hyperpolarization through the optically pumped NV electrons allows signal time savings for the measurements exceeding million-fold over conventional methods. We observe that 13 C lifetimes show a dramatic field dependence, growing rapidly with field up to ∼100mT and saturating thereafter. Through a systematic study with increasing substitutional electron (P1 center) concentration as well as 13 C enrichment levels, we identify the operational relaxation channels for the nuclei in different field regimes. In particular, we demonstrate the dominant role played by the 13 C nuclei coupling to the interacting P1 electronic spin bath. These results pave the way for quantum control techniques for dissipation engineering to boost spin lifetimes in diamond, with applications ranging from engineered quantum memories to hyperpolarized 13 C imaging.

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Room temperature "Optical Nanodiamond Hyperpolarizer": physics, design and operation

Cited by 3 publications

References 0 publications

High temperature annealing enhanced diamond 13C hyperpolarization at room temperature

High temperature annealing enhanced diamond 13C hyperpolarization at room temperature

High contrast dual-mode optical and 13C magnetic resonance imaging in diamond particles

Hyperpolarized relaxometry based nuclear T1 noise spectroscopy in diamond

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