Highly sensitive multi-stage terahertz parametric upconversion detection based on RbTiOPO4 crystalNa Ming, Shuzhen Fan, Xingyu Zhang, Xiaohan Chen, Zhenhua Cong, Zhaojun Liu, Dechun Li, Quanxin Guo, Liyuan Guo, Binzhe Jiao, Jiasheng Yuan, Kaiyu Wang and Naichang LiuEPJ Web Conf., 307 (2024) 04012DOI: https://doi.org/10.1051/epjconf/202430704012