Electrically tunable lens-enabled pixel super-resolution for on-chip holographic microscopy

In this paper, we introduce a novel, to our knowledge, on-chip holographic microscopy system that integrates an electrically tunable lens (ETL) with a super-resolution (SR) algorithm to achieve both a large-field-of-view and high-resolution imaging. A single LED is used as the point light source, which is structured through the electrically tunable system and a microscope objective. By modulating the ETL current, we enable precise z-axis movement of the point light source without the need for mechanical motion. Concurrently, the generated holograms exhibit sub-pixel shifts along the x and y axes. By employing a regularized super-resolution reconstruction algorithm, high-resolution images are obtained simultaneously. We performed full-field-of-view (FOV) reconstruction of a USAF phase resolution target (∼10.03 mm²) and achieved a lateral resolution of 1.38 μm, representing a 1.6-fold improvement over the native sensor pixel size (2.20 μm). The effectiveness of the proposed algorithm for dynamic measurements was demonstrated through real-time observations of paramecia. With its mechanical-free operation, high-throughput capability, and high-resolution imaging, this system-combining ETL and computational SR technology-holds significant potential for a wide range of applications in biological imaging.