Advanced optical design tools for high resolution imaging

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Nowadays, innovative imaging methods work by an advanced control of the lighting and imaging conditions. For example in astronomy, to image exoplanets with high contrast imaging techniques, the image of the exact predicted diffraction pattern from a star after the coronagraph is dissected to find any irregularity. These unpredicted anomalies are associated with an exoplanet around the star. This is feasible because we have models and tools to calculate the exact light behavior in the planet imager instrument. These imagers exploit the known point spread function (PSF) produced by the optical system to extract much more information that can be found from a native image. With this incredible level of knowledge, astronomers have a direct image of an exoplanet. Over the past decades, advances in astronomy inspired innovation in imaging. Laser-guided star and adaptive optics have already been transferred from astronomy to microscopy. It is therefore desirable for advanced super-resolution microscopy to predict exactly the PSF produced by the microscope. With a very detailed PSF, we will extract new information, which was previously unobtainable from the standard visual representation. Contrary to astronomy where a Fourier transform predicts the diffraction pattern, Fourier optics is no longer valid in the case of a high numerical aperture optics, and the vectorial nature of the optical fields cannot be ignored for such non-paraxial imagers. However, the lack of formalism and design tools has hindered our ability to exploit the super-resolution to its full potential. My research group works in collaboration with experts in lasers and biophotonics at the Centre for Optics, Photonics and Lasers (COPL) to advance this field. The power of modern optical design software and the non-paraxial vectorial field theory could be combined to build new unprecedented models and optical design tools to support the development of technologies for the next generation of high resolution imaging modalities. Moreover, our general model and tools will predict not only the amplitude of the PSF but also the phase and polarisation characteristics of the entire focal plane. Going beyond the intensity opens the way to many applications such as polarimetric molecular imaging. Further, direct-field electron acceleration which is facing all the concerns mentioned will also benefit from our research program. The goal of this research program is to exploit the wealth of information known to be present in the amplitude, phase and polarization currently discarded by intensity-only measurements and design tools. This will be crystallized with the development of the formalism required to know the amplitude, phase and polarization of light in extreme conditions and with the creation of tools to provide the much-needed capabilities to further advance astronomy, super-resolution microscopy and direct-field electron acceleration.