Multiple surface plasmon resonances enhanced nonlinear optical microscopy

Abstract

The nonlinear optical microscopies of coherent two-photon excited fluorescence and anti-Stokes Raman scattering are strongly enhanced by multiple surface plasmon resonances (MSPRs). The Au@Ag nanorods presented strong MSPRs peaks at 800 and 400 nm, and can enhance nonlinear optical microscopy at fundamental and double frequencies, respectively. A two-dimensional (2D) material of g-C₃N₄ is employed to study the plasmon-enhanced nonlinear optical microscopy by the femtosecond laser. The electric analysis reveals that the MSPRs of the Au@Ag nanorod can significantly enhance the signals of two-photon excited fluorescence and anti-Stokes Raman scattering by up to the orders of 10⁴ and 10¹⁶, respectively. The results demonstrate the great advantages of plasmon-enhanced nonlinear optical microscopy for the optical analysis on 2D materials, thus providing a new adventure for increasing the optical resolutions of nonlinear optical microscopy.