Nonlinear optical upconversion processes in nanoparticles, which convert long-wavelength light into short-wavelength emission, are promising for applications such as biological imaging, optical data storage and others. The flexible tuning of upconversion properties in core–shell nanoparticles now offers unprecedented control over the nonlinear optical properties of the nanoparticles.
- Feng Wang
- Renren Deng
- Xiaogang Liu
