Junjie Wei

Aug 23, 2024 | mdpi.com | Junjie Wei |Si Zhang |Shuyu Liu |Yuexia Hu

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May 14, 2024 | opg.optica.org | Jinsong Xia |Cheng Zeng |You Wu |Junjie Wei

Yellow lasers with high efficiency and tunability play an essential role in many applications. Here, we demonstrate the sum-frequency generation (SFG) of yellow light on a periodically poled thin-film lithium niobate (PP-TFLN) waveguide. Taking advantage of large χ(2) nonlinearity, a high normalized conversion efficiency of 10,097% (W·cm2) is obtained with pump wavelengths of 1317.7 and 1064 nm.

Apr 5, 2024 | onlinelibrary.wiley.com | Hua Zhang |Junjie Wei

In this paper, an susceptible–infected–susceptible (SIS) epidemic patch model with media delay is proposed at first. Then the basic reproduction number is defined, and the threshold dynamics are studied. It is shown that the disease-free equilibrium is globally asymptotically stable if and the disease is uniformly persistent if .