20世纪末、21世纪初，生命科学发展势头迅猛。三维光学显微成像技术由于能够对活体细胞内的一系列生命活动过程实施三维动态成像而倍受关注。然而，传统的基于线性荧光激发方案的共焦成像技术由于受到光学衍射极限的限制，其横向与纵向分辨率都是在数百纳米左右的量级，仍未能满足生命科学家的普遍需求。利用各种非线性光学荧光激发方案，打破光学衍射极限已经被实现，然而目前这些非线性光学成像方法在光源选择、成像光路等方面均较为复杂与昂贵。通过构筑一种具有奇异非线性光学特性的纳米粒子，在一台普通的光学显微镜上仅仅对荧光分子进行线性光激发即可实现三维远场光学超分辨成像——生命科学家长期来的梦想正有望被实现。

Three-dimensional (3D) optical microscopy has attracted tremendous attention in recent years owing to its capability of imaging into living cells. However, conventional confocal laser scanning microscopy, which is based on single-photon fluorescence excitation, can only provide a spatial resolution on the level of hundreds of nanometers due to the well-known diffraction limit. Although recently the diffraction limit has been broken using various nonlinear optical excitation approaches, 3D microscopes based on nonlinear optical effects are generally more expensive and more complex than the conventional confocal microscope. Here, we propose to achieve super-resolution in far-field optical imaging even under the linear optical excitation by use of artificially constructed silica nanoparticles with exotic nonlinear optical properties - the dream of biologists is coming true.