Nonresonant CARS Imaging of Porous and Solid Silicon Nanoparticles in Human Cells.

Coherent anti-Stokes Raman scattering (CARS), a nonlinear optical method for rapid visualization of biological objects, represents a progressive tool in biology and medicine to explore cells and tissue structures in living systems and biopsies. In this study, we report efficient nonresonant CARS imaging of silicon nanoparticles (SiNPs) in human cells as a proof of concept. As both bulk and porous silicon exhibit a high third-order nonlinear susceptibility, χ, which is responsible for the CARS intensity, it is possible to visualize the SiNPs without specific labels.