title: Diffractionless beam in free space with adiabatic changing refractive index in a single mode tapered slab waveguide.
abstract: We propose a novel design to produce a free space diffractionless beam by adiabatically reducing the difference of the refractive index between the core and the cladding regions of a single mode tapered slab waveguide. To ensure only one propagating eigenmode in the adiabatic transition, the correlation of the waveguide core width and the refractive index is investigated. Under the adiabatic condition, we demonstrate that our waveguide can emit a diffractionless beam in free space up to 500 micrometers maintaining 72% of its original peak intensity. The proposed waveguide could find excellent applications for imaging purposes where an extended depth of field is required.
authors.affiliation: Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA. Tsai.Chang-Ching@mgh.harvard.edu
authors.forename: Chang-Ching
authors.initials: CC
authors.lastname: Tsai
authors.forename: Claudio
authors.initials: C
authors.lastname: Vinegoni
authors.forename: Ralph
authors.initials: R
authors.lastname: Weissleder
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D003460:Crystallization; D003952:Diagnostic Imaging / Q000379:methods; D004867:Equipment Design; D007909:Lenses; D008027:Light; D008853:Microscopy / Q000295:instrumentation / Q000379:methods; D015233:Models, Statistical; D008962:Models, Theoretical; D055095:Optics and Photonics; D017785:Photons; D010825:Physics / Q000379:methods; D012031:Refractometry