Fluorescence microscopy is an indispensable tool in biology and medicine, fuelling many breakthrough discoveries in a wide set of sub-domains. Yet, the resolution is intrinsically restricted by the diffraction limit. The last two decades have witnessed the emergence of several super-resolution fluorescence microscopy techniques that are breaking this limit (cfr. Nobel Prize in Chemistry 2014). Structured illumination microscopy (SIM) is one of such techniques that has gained much popularity and is available in commercial systems. In SIM, a biological sample is illuminated by a spatially structured light field — a sinusoidal interference pattern — which causes normally inaccessible high-resolution information to be encoded into the observed image due to the Moiré effect. Typically, the illumination patterns are generated by a grating or SLM and focused onto the sample through an objective lens to excite the fluorophores. Next, the fluorescence is transmitted to the imager through the same lens. Multiple images are taken under certain illumination patterns and used to reconstruct a single super-resolved image. However, making use of free space optics, state-of-the-art SIM systems require multiple bulky and precision optical components that give these systems the drawbacks of high cost and cumbersome size.
In this talk, a structured illumination microscopy system based on a photonic integrated circuit (PIC) is presented. The unique properties of photonic integrated circuits allow us to create truly innovative microscopy systems that have the potential to go well beyond the current state-of-the-art: higher resolution due to the use of high refractive index materials, easier alignment with on-chip illumination light path, large field of view, a compact form factor resulting from on-chip integration, and lower cost due to compatibility with CMOS chip fabrication.