Adaptive Focal Length Imaging System using Liquid Crystal Spatial Light Modulator

In this paper, we present a single-lens based imaging system that its focal length can be adjusted by using Liquid Crystal Spatial Light Modulator (LC-SLM). The SLM is placed at the aperture stop of the imaging system to work as a Phase Mask (PM) that modifies the light wavefront passing the exit pupil. By changing the pixel-based PM pattern that sends to the SLM, the focal length of the imaging system can be varied in the same spirit as conventional mechanical-zoom lenses. We demonstrate a proof-of-concept system for high magnification industrial inspection applications in a laboratory setup. We show the results that the focal length of the system is adjustable within the range ±2.0mm.