We propose a scalable and practical implementation of spin amplification which does not require individual addressing nor a specially tailored spin network. We have demonstrated a gain of 140 in a solid-state nuclear spin system of which the spin polarization has been increased to 0.12 using dynamic nuclear polarization with photoexcited triplet electron spins. Spin amplification scalable to a higher gain opens the door to the single spin measurement for a readout of quantum computers as well as practical applications of nuclear magnetic resonance (NMR) spectroscopy to infinitesimal samples which have been concealed by thermal noise.
@article{arxiv.1105.4740,
title = {Scalable Spin Amplification with a Gain over a Hundred},
author = {Makoto Negoro and Kenichiro Tateishi and Akinori Kagawa and Masahiro Kitagawa},
journal= {arXiv preprint arXiv:1105.4740},
year = {2015}
}