title: High refractive index Fresnel lens on a fiber fabricated by nanoimprint lithography for immersion applications.
abstract: In this Letter, we present a Fresnel lens fabricated on the end of an optical fiber. The lens is fabricated using nanoimprint lithography of a functional high refractive index material, which is suitable for mass production. The main advantage of the presented Fresnel lens compared to a conventional fiber lens is its high refractive index (n=1.68), which enables efficient light focusing even inside other media, such as water or an adhesive. Measurement of the lens performance in an immersion liquid (n=1.51) shows a near diffraction limited focal spot of 810 nm in diameter at the 1/e2intensity level for a wavelength of 660 nm. Applications of such fiber lenses include integrated optics, optical trapping, and fiber probes.
authors.forename: Alexander
authors.initials: A
authors.lastname: Koshelev
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Calafiore
authors.forename: Carlos
authors.initials: C
authors.lastname: Piña-Hernandez
authors.forename: Frances I
authors.initials: FI
authors.lastname: Allen
authors.forename: Scott
authors.initials: S
authors.lastname: Dhuey
authors.forename: Simone
authors.initials: S
authors.lastname: Sassolini
authors.forename: Edward
authors.initials: E
authors.lastname: Wong
authors.forename: Paul
authors.initials: P
authors.lastname: Lum
authors.forename: Keiko
authors.initials: K
authors.lastname: Munechika
authors.forename: Stefano
authors.initials: S
authors.lastname: Cabrini