ARC Centre of Excellence for Engineered Quantum Systems, School of Physics, University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Australia.
G.G. Devyatykh Institute of Chemistry of High-Purity Substances of the Russian Academy of Sciences, 49 Tropinin Str., Nizhny Novgorod 603950, Russia.
Sci Rep. 2017 Mar 20;7:44813. doi: 10.1038/srep44813.
The low dielectric losses of an isotopically pure single crystal Si sample were determined at a temperature of 20 mK and at powers equivalent to that of a single photon. Whispering Gallery Mode (WGM) analysis revealed large Quality Factors of order 2 × 10 (dielectric loss ~5 × 10) at high powers, degrading to 7 × 10 (dielectric loss ~1.4 × 10 at single photon energy. A very low-loss narrow line width paramagnetic spin flip transition was detected with extreme sensitivity in Si, with very small concentration below 10 cm (less than 10 parts per trillion) and g-factor of 1.995 ± 0.008. Such determination was only possible due to the low dielectric photonic losses combined with the long lifetime of the spin transition (low magnetic loss), which enhances the magnetic AC susceptibility. Such low photonic loss at single photon energy combined with the narrow line width of the spin ensemble, indicate that single crystal Si could be an important crystal for future cavity QED experiments.
在 20mK 的温度下，对同位素纯单晶硅样品的低介电损耗进行了测定，功率相当于单个光子的功率。 whisperinggallerymode（WGM）分析表明，在高功率下，品质因数高达 2×10（介电损耗5×10），在单光子能量下降低到 7×10（介电损耗1.4×10）。在 Si 中检测到极低损耗的窄线宽顺磁自旋翻转跃迁，具有极高的灵敏度，浓度低于 10cm（低于 10 万亿分之一），g 因子为 1.995±0.008。由于低介电光损耗与自旋跃迁的长寿命（低磁损耗）相结合，使得磁交流磁化率增强，因此只有这样才能进行这种低光子能量的损耗测定。这种单光子能量下的低介电损耗与自旋系综的窄线宽相结合，表明单晶硅可能是未来腔量子电动力学实验的重要晶体。
