Morin Corentin, Tignon Jérôme, Mangeney Juliette, Dhillon Sukhdeep, Czajkowski Gerard, Karpiński Karol, Zielińska-Raczyńska Sylwia, Ziemkiewicz David, Boulier Thomas
Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, 75005 Paris, France.
Bydgoszcz University of Science and Technology 7 Kaliskiego Ave., 85-796 Bydgoszcz, Poland.
Phys Rev Lett. 2022 Sep 23;129(13):137401. doi: 10.1103/PhysRevLett.129.137401.
We investigate the nonlinear refraction induced by Rydberg excitons in Cu_{2}O. Using a high-precision interferometry imaging technique that spatially resolves the nonlinear phase shift, we observe significant shifts at extremely low laser intensity near each exciton resonance. From this, we derive the nonlinear index n_{2}, present the n_{2} spectrum for principal quantum numbers n≥5, and report large n_{2} values of order 10^{-3} mm^{2}/mW. Moreover, we observe a rapid saturation of the Kerr nonlinearity and find that the saturation intensity I_{sat} decreases as n^{-7}. We explain this with the Rydberg blockade mechanism, whereby giant Rydberg interactions limit the exciton density, resulting in a maximum phase shift of 0.5 rad in our setup.
我们研究了氧化亚铜中里德堡激子诱导的非线性折射。使用一种能在空间上分辨非线性相移的高精度干涉成像技术，我们在每个激子共振附近的极低激光强度下观察到了显著的相移。由此，我们推导出非线性折射率(n_{2})，给出了主量子数(n\geq5)时的(n_{2})光谱，并报告了(10^{-3}) (mm^{2}/mW)量级的大(n_{2})值。此外，我们观察到克尔非线性的快速饱和，并发现饱和强度(I_{sat})随(n^{-7})减小。我们用里德堡阻塞机制来解释这一现象，即巨大的里德堡相互作用限制了激子密度，导致在我们的实验装置中最大相移为(0.5)弧度。
