Optical imaging system with extended-depth-of-field based on large-aperture liquid crystal axicon lens

The optical imaging systems with optical sectioning capabilities are widely used for acquiring 3D structural images of volumetric samples. The core component of the imaging system with optical sectioning capabilities is the tunable lens, but traditional optical imaging systems often face the challenge of limited depth of field. Here, a liquid crystal (LC) axicon lens with large aperture (20 mm) is directly employed to extend the depth-of-field in our optical imaging system. The depth-of-field range of the imaging system extends to 380 mm due to the inherent large depth of focus characteristic. Combined with the liquid lens system, the system possesses the inherent potential for continuous electronic zoom. The system's performance is assessed through the use of resolution target, calendar target and large-spacing letter samples to evaluate image resolution and contrast ratio. In addition, image processing algorithms are used to eliminate the ghosting of the captured images by the system. The proposed compact incoherent optical imaging system, utilizing the LC axicon lens, offers significant potential for applications in microscopy and astronomy, particularly for extended depth-of-field imaging.