title: Planar high-numerical-aperture low-loss focusing reflectors and lenses using subwavelength high contrast gratings.
abstract: We propose planar, high numerical aperture (NA), low loss, focusing reflectors and lenses using subwavelength high contrast gratings (HCGs). By designing the reflectance and the phase of non-periodic HCGs, both focusing reflectors and lenses can be constructed. Numerical aperture values as high as 0.81 and 0.96 are achieved for a reflector and lens with very low losses of 0.3 and 0.2 dB, respectively. The design algorithm is also shown to be readily extended to a 2D lens. Furthermore, HCG optics can simultaneously focus the reflected and transmitted waves, with important technological implications. HCG focusing optics are defined by one-step photolithography and thus can be readily integrated with many devices including VCSELs, saturable absorbers, telescopes, CCDs and solar cells.
authors.affiliation: Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA 94720, USA.
authors.forename: Fanglu
authors.initials: F
authors.lastname: Lu
authors.forename: Forrest G
authors.initials: FG
authors.lastname: Sedgwick
authors.forename: Vadim
authors.initials: V
authors.lastname: Karagodsky
authors.forename: Christopher
authors.initials: C
authors.lastname: Chase
authors.forename: Connie J
authors.initials: CJ
authors.lastname: Chang-Hasnain