Broadband Optical Edge Detection Based on Two-Dimensional Liquid Crystal Polarization Grating

A two-dimensional liquid crystal polarization grating (2D-LCPG) is realized by using a single-exposure photoalignment system. When using a horizontal polarized light as the reference incident light, four circular polarized light beams are captured with a 4f system to realize image extraction and detection. Compared with a 1D-LCPG, the experimental results demonstrate better integrity and accuracy in extracting edge information with the proposed 2D-LCPG. Broadband edge detection capability was tested under visible wavelength range. Results show good edge detection even without an electric field. The resolutions are up to 15.63 µm for incident light of 633 nm, 532 nm by applying a 0.3 V/µm electric field, and 450 nm by applying a 0.5 V/µm electric field. With these advantages, optical edge detection based on the proposed 2D-LCPG could have potential applications in image processing, remote sensing, and other related areas.