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Improving the tissue penetration depth and spatial resolution of fluorescence-based optical nanoprobes remains a grand challenge for their practical applications in in vivo imaging, due to the scattering and absorption and endogenous autofluorescence of living tissues. Here, we present that Ag2S quantum dots (QDs), containing no toxic ions, exhibiting long circulation time and high stability, act as a new kind of fluorescent probes in the second near-infrared window (NIR-II, 1000-1350 nm) which enable in vivo monitoring of lymphatic drainage and vascular networks with deep tissue penetration and high spatial and temporal resolution. In addition, NIR-II fluorescence imaging with Ag2S QDs provide ultrahigh spatial resolution (~40 μm) that permits us to track angiogenesis mediated by a tiny tumor (2-3 mm in diameter) in vivo. Our results indicate that Ag2S QDs are promising NIR-II fluorescent nanoprobes that could be useful in surgical treatments such as sentinel lymph node (SLN) dissection as well in assessment of blood supply in tissues and organs and screening of anti-angiogenic drugs., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Structured light projection provides a promising approach to achieving fast and non-contact three-dimensional (3D) imaging. The resolution is a crucial index that represents security and accuracy in applications such as face recognition and robot vision. It depends on the density of dots in the projection. However, further improving the density of dots in the current system must be at the cost of speed or volume. Here, an all-dielectric ultra-thin metasurface is designed and fabricated to project a multi-wavelength dot array. The density of dots is improved because projected dots with different wavelengths fill the gaps with each other. The experimental results demonstrate that the multi-wavelength projection improves the resolution of 3D imaging. Furthermore, the multi-wavelength system is beneficial to measuring a surface with varying colors. The approach has the potential to achieve a new generation of high-resolution systems for tiny fluctuations and colorful 3D imaging in dark environments. [ABSTRACT FROM AUTHOR]