Wide-field structured illumination microscopy for fluorescence and pump-probe imaging

Abstract

The optical resolution of microscopy is limited by the wave-like characteristic of the light. There are many recent advances in overcoming this diffraction limited resolution, but mostly focused on fluorescent imaging. Furthermore, there are few non-fluorescence wide-field super-resolution techniques that can fully utilize the applicable laser power to optimize imaging speed. Structured illumination microscopy is a super-resolution method that relies on patterned excitation. This thesis has presented novel applications of structured illumination microscopy to surface plasmon resonance fluorescence and pump-probe scattering imaging. First, structured illumination microscopy was introduced to surface plasmon resonance fluorescence imaging for high signal-to-noise and high resolution. Secondly, a theoretical framework for three-dimensional wide-field pump-probe structured illumination microscopy has been developed to increase the lateral resolution and enable depth sectioning. Further, structured illumination wide-field photothermal digital phase microscopy is proposed as a high throughput, high sensitivity super-resolution imaging tool to diagnose ovarian cancer. Finally, I have derived the exact analytical solution to the heat conduction problem in which a sphere absorbs temporally modulated laser beam for photothermal microscopy. The proposed method also has a great potential to be applied to other pump-probe modalities such as transient absorption and stimulated Raman scattering.