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Published a paper in Nano Letters as a cover article

Jul 16, 2020

Upconversion Nonlinear Structured Illumination Microscopy

Video-rate super-resolution imaging through biological tissue can visualize and track biomolecule interplays and transportations inside cellular organisms. Structured illumination microscopy allows for wide-field super resolution observation of biological samples but is limited by the strong extinction of light by biological tissues, which restricts the imaging depth and degrades its imaging resolution. Here we report a photon upconversion scheme using lanthanide-doped nanoparticles for wide-field super-resolution imaging through the biological transparent window, featured by near-infrared and low-irradiance nonlinear structured illumination. We demonstrate that the 976 nm excitation and 800 nm upconverted emission can mitigate the aberration. We found that the nonlinear response of upconversion emissions from single nanoparticles can effectively generate the required high spatial frequency components in the Fourier domain. These strategies lead to a new modality in microscopy with a resolution below 131 nm, 1/7th of the excitation wavelength, and an imaging rate of 1 Hz.

Published a paper in Nanoscale

Jun 29, 2020

Video-rate upconverting display by optimizing lanthanide doped nanoparticles

Volumetric displays that create bright image points within a transparent bulk is one of the most attracting technologies in everyday life. Lanthanide ions doped upconversion nanoparticles (UCNPs) is an promising luminescent nanomaterial for the background free, full-colour volumetric displaying within transparent bulk materials. However, video-rate display using UCNPs was limited from their low emission intensity. Here we developed a video-rate upconverting display system with much enhanced brightness. The integral emission intensity of the single UCNPs was fully employed for video-rate display. It was maximized by optimizing the emitter concentration and, more imporatantly, by temporally synchronizing the scanning time of the excitation light to the emission raising time of single UCNPs. The excitation power dependent emission response and emission’s time decay curves were systematically characterized for single UCNPs with varied emitter concentrations from 0.5% to 6%. 1%Tm3+ doped UCNPs presented highest integral emission intensity. By embedding this UCNPs into a PVA film, we achieved a two-dimensional (2D) upconverting display with frame rate of 29 Hz for 35 by 50 pixels. This work demonstrates that the temporal response as well as the integral emission intensity enable video-rate upconverting display.

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