title: Structured lens formed by a 2D square hole array in a metallic film.
abstract: A method is proposed to modulate phase using variant square holes in a metallic film based on a fundamental mode approximation model. Phase retardation through square holes in a subwavelength scale in a thin metal film has been analyzed and calculated. Based on the model, a structured lens with a numerical aperture of 0.583 and a focal length of 240 microm formed by a 2D square hole array in a metallic film is designed. Numerical simulation using the finite-difference time-domain method is carried out, and the results agree with the theoretical analysis. A focal spot close to the diffraction limit can be obtained.
authors.affiliation: State Key Laboratory of Optical Technologies for Microfabrication, Institute of Optics and Electronics, Chinese Academy of Sciences, Chengdu, Sichuan Province, China.
authors.forename: Yanzhong
authors.initials: Y
authors.lastname: Chen
authors.forename: Chongxi
authors.initials: C
authors.lastname: Zhou
authors.forename: Xiangang
authors.initials: X
authors.lastname: Luo
authors.forename: Chunlei
authors.initials: C
authors.lastname: Du