Pradhan Amit Kumar, Kumar Suman, Ballav Swastik, Priyam Amiya, Datta Prasanta Kumar
Opt Lett. 2024 Oct 15;49(20):5985-5988. doi: 10.1364/OL.541804.
This study investigates the coherent optical nonlinearity of two sets of anisotropic silver nanocrystals (NCs) showing plasmon peaks at 530 and 610 nm (hence named Ag-530 and Ag-610 NCs, respectively). The nonlinear optical (NLO) properties of Ag-530 and Ag-610 NCs are compared with spherical silver NCs exhibiting plasmon peak at 420 nm (hence called Ag-420 NCs). Resonant excitation induces significant one-photon absorption (1PA) saturation for all NCs, with Ag-610 NCs displaying exceptional transparency. Off-resonant excitation reveals efficient two-photon (2PA), three-photon (3PA), and saturable (SA) absorption in Ag-610 NCs. In the 3PA regime, the effective nonlinear absorption coefficient of Ag-610 NCs is 221% and 340% that of Ag-420 and Ag-530 NCs, respectively, at a laser intensity of 40 GW/cm. The impressive absorption figures of merit of Ag-610 NCs make it the ultimate contender for high-performance 2PA and 3PA applications.
本研究调查了两组各向异性银纳米晶体（NCs）的相干光学非线性，这两组纳米晶体分别在530和610 nm处呈现等离子体峰（因此分别命名为Ag - 530和Ag - 610 NCs）。将Ag - 530和Ag - 610 NCs的非线性光学（NLO）特性与在420 nm处呈现等离子体峰的球形银纳米晶体（因此称为Ag - 420 NCs）进行了比较。共振激发会使所有纳米晶体产生显著的单光子吸收（1PA）饱和现象，其中Ag - 610 NCs表现出特别的透明度。非共振激发揭示了Ag - 610 NCs中存在有效的双光子（2PA）、三光子（3PA）和饱和（SA）吸收。在3PA模式下，在激光强度为40 GW/cm时，Ag - 610 NCs的有效非线性吸收系数分别是Ag - 420和Ag - 530 NCs的221%和340%。Ag - 610 NCs令人印象深刻的吸收品质因数使其成为高性能2PA和3PA应用的最终竞争者。
