Structured illumination microscopy (SIM) is a powerful imaging technique that enables resolution enhancement beyond the diffraction limit while preserving low phototoxicity and compatibility with conventional fluorescence microscopy. Traditional SIM implementations, however, typically rely on complex and bulky optical systems, limiting their robustness and widespread adoption.

In this talk, femtosecond laser micromachining (FLM) will be presented as a versatile enabling technology for the fabrication of three-dimensional integrated photonic circuits in glass for structured illumination microscopy. By inducing localized refractive index modifications inside transparent materials, FLM enables the direct writing of buried optical waveguides, directional couplers, and interferometric structures with true three-dimensional design freedom and micrometric precision. When combined with selective chemical etching (FLICE), the same technology also allows the fabrication of reflective micro-optical elements, including flat and curved mirrors, which are subsequently metal-coated to guide the beams and generate structured illumination patterns. Thermal phase shifters integrated onto the chip surface provide fast, dynamic control of the relative phase between the interfering beams without mechanical movement, enabling the pattern translation required for SIM image reconstruction.

Different device architectures will be presented, ranging from compact two-output interferometers to more sophisticated multi-beam photonic circuits capable of generating both two- and three-dimensional interference patterns. The resulting glass chips can be directly interfaced with conventional widefield microscopes, transforming them into compact and reconfigurable SIM platforms. Overall, the presented work highlights the unique capabilities of femtosecond laser micromachining for the rapid prototyping and fabrication of complex three dimensional integrated photonic systems, opening new opportunities for compact, alignment-free, and field deployable super-resolution imaging devices.