Low-aberration liquid crystal lens with positive and negative focal length

A low-aberration hole-patterned-electrodes (HPE) liquid crystal (LC) lens with positive and negative focal lengths is demonstrated in this Letter by using four hybrid-aligned nematic LC layers filled with dual-frequency LC materials. The diopter can be controlled from the positive lens (0D∼1.1D) to the negative lens (0D∼-1.25D). The aberration is analyzed using the Zernike polynomial, and the wavefront optical path difference is improved from 2λ for the conventional one-layer HPE LC lens to less than 0.25λ for our proposed LC lens. The proposed LC lens does not require the use of a polarizer, increasing the optical efficiency two times compared with the conventional LC lens.