Design method to enhance the transmittance of a structured lens based on nonperiodic sampling

Abstract

On the basis of the work of Chen, Zhou, Luo, and Du [Opt. Lett. 33, 753-755 (2008)], we propose a new method using nonperiodic sampling to design a high-transmittance structured lens. The sizes of the holes are decided by the phase requirements, and the holes are arranged with a fixed interval in the vertical direction while a variable interval in the horizontal direction. With this design method, holes can be arranged more compactly and the fill factor of the holes can be increased effectively. Numerical simulation is performed through the finite-difference time-domain method, and the results indicate that the transmittance of the lens climbs to 73.6%, which reaches almost 3.5 times that achieved in the above-mentioned work. Meanwhile, the simulated focal length agrees well with the theoretical design result with the error of 1.1% and the full width at half maximum of the focal spot is obtained similar to 1.16 times of the diffraction limit. (C) 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.3528539]