Scanning Diffracted-Light Microscopy SDLM
MetadataShow full item record
In this research work, I explored several extensions of Fourier ptychography microscopy (FPM) and dual space microscopy (DSM) techniques which are well known imaging techniques, used to produce images with high resolution and large field of view (FOV) and recover the phase. Although these techniques work good for inclined illumination, however, these techniques cannot be used without modification when the sample is illuminated by a cone of light produced by a condenser because in this case the sample is illuminated simultaneously from different directions. Firstly, I used the extended version of FPM as illumination direction multiplexing IDM-FPM, in which multiple illumination light beams are multiplexed together to create an image. In this work I present an inexpensive but practical implementation of the IDM-FPM technique involving a ring-shaped condenser emitting a hollow-cone of light, with a numerical aperture larger than the objective lens, to be incident on a periodic sample (also containing non-periodic structure). Image diversity was obtained by introducing a slit in the back focal plane of the objective lens, that was rotated to obtain several diversified Fourier plane and real plane images. I simulated, discussed, and demonstrated processing of experimental images using a combination of the Fourier plane imaging microcopy FPIM technique and the IDM-FPM algorithm, which rapidly converged to a high-resolution RP image surpassing the Rayleigh resolution limit capable of producing a high-resolution image of the sample after processing the experimental images. Secondly, I explored and presented an extension of the dual-space microscopy (DSM) and Fourier ptychographic microscopy (FPM) algorithms adapted for imaging samples simultaneously illuminated by multiple beams coherent with each other. The modified algorithms were successfully tested using the light diffracted by a Ronchi-ruling as the source of illumination. High-resolution images with a resolution better than the Rayleigh resolution limit were demonstrated. Lastly, I demonstrated the scanning diffracted light microscopy (SDLM) technique, where by scanning the direction of the light that is diffracted by a sample permits achieving the image diversity, which is necessary for implementing the Fourier ptychographic microscopy technique (FPM) using only perpendicular illumination. I also demonstrated that the same method allows for implementation of the illumination-direction-multiplexing FPM technique when the sample is illuminated using a ring-shaped condenser by implementing and presenting proof-of-concept experiments which are in good agreement with simulations. IDM-SDLM will allow for improving the resolution of microscope-condenser arrangements that are ubiquitous in biomedical labs This technique can have applications where microscopes or telescopes are used for imaging the phase of the optical disturbance OD. In addition, if the numerical aperture of the condenser is very large than the numerical aperture of the objective lens, then IDM-SDLM could be used to provide alternate way to image nanostructures.