Youhua Chen

Enhancement of fluorescence emission difference microscopy using conjugated vortex phase modulation: ENHANCEMENT OF FLUORESCENCE EMISSION DIFFERENCE MICROSCOPY

In this paper, we propose and demonstrate an improved fluorescence emission difference microscopy (FED) method, exploiting programmable phase modulation for image enhancement. The main novelty of the proposed approach lies in the matched size and intensity of two excitation spots. The proposed method improves the FED performance on image quality via artefact elimination. We demonstrate the feasibility of this method through theoretical studies and experimental tests. The experimental results of nanobeads and cells validate the practical performance of this method, which can enable reliable observations at superresolution in biomedical studies.

Saturated pattern-illuminated Fourier ptychography microscopy

We report a series of simulation studies which extends pattern-illuminated Fourier ptychography microscopy by integrating with the nonlinearity arising from saturation of the fluorophore excited state for super-resolution fluorescence imaging. This extended technique, termed Saturated pattern-illuminated Fourier ptychography (SpiFP) microscopy, could achieve a resolution four times that of wide field when the illuminating light intensity approaches the saturation threshold in simulations. Increasing light intensity leads to further resolution enhancement. In order to demonstrate the performance of SpiFP, we make a comparison between SpiFP and saturated structure illumination microscopy in simulations, and prove that the SpiFP exhibits superior robustness to noise, aberration correcting ability, and patterns flexibility. Introducing the saturation of the fluorescent emission brings in notable improvements in imaging performance, implying its potential in nanoscale-sized biological observations by wide-field microscopy.

Demonstration of Multi-mode Parallel Detection Microscopy

Four resolution enhancement microscopy methods based on parallel detection are investigated containing confocal microscopy with four pinhole sizes, Fluorescence Emission Difference Microscopy (FED) based on parallel detection, Airyscan microscopy and Virtual k-vector modulation optical microscopy (Vikmon).