Image based on wavefront sensorless adaptive optics in Fresnel incoherent correlation digital holography

Wavefront distortions or phase aberrations usually degrade the performance of imaging systems, thus limit the imaging resolution and image quality. Adaptive optics (AO) is proposed and developed in order to remove the effect of optical aberrations. Traditional AO systems use wavefront sensors (such as the Shaker-Hartmann sensor) to measure wavefront errors. Development of wavefront-sensorless adaptive optics in recent years eliminates the need for wavefront sensors, which simplifies system structure, reduces the cost and overcomes some limitations of traditional adaptive optics. In this paper, we focus on the implementation of Image-based wavefront-sensorless adaptive optics in Fresnel Incoherent Correlation Digital Holography (FINCH) to improve the imaging quality. Zernike polynomials are introduced to describe aberrations, sharpness and intensity are employed to evaluate the imaging quality dynamically, and the measurement and compensation are implemented combining with curve fitting algorithm. We implemented this method in FINCH system, which can achieve incoherent holograms by using the correlation between the object information and the image of a pinhole. A phase mask is mounted on a SLM to split the beam and shift phase to suppress the twin images in the reconstruction. Both the aberration and the phase mask were introduced by SLM. The image-based wavefront-sensorless adaptive optics is investigated experimentally in a FINCH imaging system.