Super‐Resolution by Structured Illumination: Digital Holographic Microscopy for Metrology of Nanomaterials

Digital holographic microscopy (DHM) resolution, constrained by the emission wavelength and numerical aperture, can be enhanced through structured illumination techniques. This article introduces a structured illumination microscopy method utilizing a speckle pattern generated by a Scotch tape diffuser to achieve super‐resolution (SR) quantitative phase imaging. The SRAD‐DIHM system (SR using alternating direction method of multipliers (ADMM) in digital in‐line holographic microscopy) combines speckled illumination and ADMM‐based computations for SR. By incorporating sparsity‐based regularization, the system mitigates the speckle noise inherent in speckled illumination. The SRAD‐DIHM system provides a threefold improvement in lateral resolution and a ninefold improvement in axial resolution over conventional DHM. The work effectively uses SRAD‐DIHM for label‐free imaging and metrology of nanoparticles.