Multi-Periodic Structured Illumination Microscopy based on Co-linear Hexa Mirror geometry

Structured illumination microscopy (SIM) is a powerful widefield nanoscopy technique known for enhancing resolution by $\sim 2$-fold. Despite various advancements aimed at pushing its resolution limits, achieving high resolution across a large field of view (FOV) remains a significant challenge. In this work, we introduce a tilt-mirror-based multi-periodic SIM (mMP-SIM) approach that enables super-resolution imaging over a wide area. This method utilizes six-beam interference patterns, generated via a specially designed mirror mount, to illuminate the sample with multi-periodic structured light. Using a $20 X / 0.40$ numerical aperture objective lens, we demonstrate a 3.16-fold resolution enhancement across a large-FOV $\left(0.53 \times 0.34 \mathrm{~mm}^{2}\right)$. This represents a 9.98-fold improvement in space-bandwidth product, addressing key limitations in large-area imaging. Furthermore, by decoupling the illumination and detection pathways, mMPSIM offers scalability for high-resolution imaging across extended areas. With a $28 X / 0.80$ NA objective, we achieve an optical resolution of 170 nm over a $(0.40 \times 0.25) \mathrm{mm}^{2}$ area. The system’s capabilities are validated through experiments on both for fluorescent beads as well as bio-sample like U2OS (human bone osteosarcoma) cells.