title: Scanning microscopy using a short-focal-length Fresnel zone plate.
abstract: We demonstrate a form of scanning microscopy using a short-focal-length Fresnel zone plate and a low-NA relay telescope. Owing to a focal length of only 5 microm, the zone plate produces large wavefront tilt and consequently severe vignetting for off-axis illumination. By scanning an optically trapped fluorescent sphere, we measure the vignetted collection region of the zone-plate imaging system. The fluorescence collection efficiency is sharply peaked and has a lateral width of 550 nm, which agrees with numerical simulations.
authors.affiliation: School of Engineering and Applied Science, Harvard University, Cambridge, MA 02138, USA. schonbru@seas.harvard.edu
authors.forename: Ethan
authors.initials: E
authors.lastname: Schonbrun
authors.forename: Winnie N
authors.initials: WN
authors.lastname: Ye
authors.forename: Kenneth B
authors.initials: KB
authors.lastname: Crozier