Highly Nonlinear Luminescence Induced by Gold Nanoparticles on Glass Surfaces with Continuous-Wave Laser Illumination

TL;DR

This paper reports on the observation of highly nonlinear luminescence from individual gold nanoparticles on glass surfaces under low-power continuous-wave laser illumination, enabling super-resolution imaging and potential biological applications.

Contribution

It demonstrates a novel nonlinear luminescence phenomenon in gold nanoparticles induced by low-power CW lasers, with implications for super-resolution and deep tissue imaging.

Findings

Luminescence intensity scales with the 5th--7th power of laser power.

Nonlinear luminescence is prominent near glass surfaces.

Potential for biological super-resolution imaging.

Abstract

We report on highly nonlinear luminescence being observed from individual spherical gold nanoparticles immobilized on a glass surface and illuminated by continuous-wave (CW) lasers with relatively low power. The nonlinear luminescence shows optical super-resolution beyond the diffraction limit in three dimensions compared to the scatting of the excitation laser light. The luminescence intensity from most nanoparticles is proportional to the 5th--7th power of the excitation laser power and has wide excitation and emission spectra across the visible wavelength range. Strong nonlinear luminescence is only observed near the glass surface. High optical nonlinearity excited by low CW laser power is related to a long-lived dark state of the gold nanoparticles, where the excitation light is strongly absorbed. This phenomenon has potential biological applications in super-resolution and deep tissue imaging.