High refractive index Fresnel lens on a fiber fabricated by nanoimprint lithography for immersion applications

TL;DR

This paper introduces a high refractive index Fresnel lens fabricated on an optical fiber end using nanoimprint lithography, enabling efficient light focusing in immersion media for applications like optical trapping and fiber probes.

Contribution

It demonstrates a novel high refractive index fiber Fresnel lens fabricated via nanoimprint lithography, suitable for mass production and immersion applications.

Findings

Achieved a near diffraction limited focal spot of 810 nm at 660 nm wavelength.

Demonstrated effective light focusing in immersion media with n=1.51.

Fabricated lens shows potential for integrated optics and optical trapping.

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=1.69), which enables efficient light focusing even inside other media such as water or 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/e2 intensity level for a wavelength of 660 nm. Applications of such fiber lenses include integrated optics, optical trapping and fiber probes.