Amplitude- and Phase-Programmable Dual-Color Photonic Chip for High-Contrast Structured Illumination Microscopy.

Advanced optical microscopy techniques, such as structured illumination microscopy (SIM), often rely on precise and complex illumination setups, which can be challenging to implement and maintain. Integrated optics can offer compact, stable, and easy-to-align alternatives, enabling efficient light manipulation for advanced imaging applications. We present an integrated photonic device that generates structured illumination patterns directly within an optical microscope. The device incorporates optical waveguides in a Mach-Zehnder interferometer configuration, generating two separate coherent point sources with controlled amplitudes and phases. When optically conjugated to the pupil plane of a conventional widefield microscope, the device generates sinusoidal illumination patterns in the object plane, which can be translated and modulated via the Mach-Zehnder interferometer. We demonstrate that amplitude modulation enables (i) optical sectioning in HiLo (High and Low Frequency Illumination) microscopy and (ii) controlled structured illumination contrast across multiple wavelengths, making the system adaptable for multicolor SIM. Our results highlight the potential of integrated photonics as a compact and robust approach for advanced microscopy techniques, contributing to the development of simplified, high-resolution structured illumination imaging in biomedical and materials science applications.