Advances in nanoscale fabrication provide access to the smallscale phenomena that underpin fi elds of research such as plasmonics and subwavelength optics. [ 1 ] The choice of substrate for these nanostructures can defi ne the scope of their utility. Nanostructures on an optical-fi ber facet obtain the advantages of a miniaturized substrate that can be interrogated remotely and deployed in vivo and in vitro. However, fabrication on fi ber facets is challenging, because of their unusually small 125 μ m diameter and their large aspect ratio. To date, demonstrations of fi ber-facet nanopatterning have used interference lithography (IL), [ 2 ] electron-beam lithography (EBL) [3][4][5] and focused ion-beam lithography (FIB) [ 6 , 7 ] as fabrication techniques. The transfer of EBL nanostructures to fi ber facets has also been demonstrated, [ 8 , 9 ] achieving 25 nm feature separations. However, IL can produce only limited geometries, while EBL and FIB are unsuited to high-throughput fabrication.In contrast, nanoimprint lithography (NIL) provides largearea, high-resolution nanofabrication at low cost and highthroughput. New platforms that have been explored for NIL include mask aligners, [ 10 ] roll-to-roll imprinting, [ 11 ] optical-fi ber lengths [ 12 ] and optical-fi ber-facets (OFF-NIL). To date, OFF-NIL has demonstrated periodic diffraction features with dimensions 250 nm, [ 13 ] and 630 nm, [ 14 , 15 ] and nanorods for surface-enhanced Raman scattering (SERS) with diameters ∼ 110 nm. [ 16 ] All of these demonstrations of fi ber-facet nanopatterning have been limited to single-fi ber processing. Given the typical facet diameter of 125 μ m, there is clear opportunity for increased throughput via parallel OFF-NIL with large-area molds. Fiber-ribbons would seem an appropriate candidate for parallel fabrication, [ 17 ] however these are restricted in the type and number of fi bers available, and require specialized stripping and cleaving tools. Additionally, the cleaved ribbon-facets are restricted to a single plane.In this paper, we demonstrate an elegant, low-cost, highly accessible platform for imprinting arrays of optical-fi ber facets.We show that by segmenting optical-fi bers into short lengths and loading them into separate U-grooves, many fi bers can be imprinted in parallel. Over-sizing these U-grooves enables the fi bers to independently slide back-and-forth, and to self-align once they contact the mold, eliminating the need for critical proximity control during imprinting. Using this platform, we have achieved sub-15 nm feature separations across fi ber arrays. Further, using this system with large-area molds eliminates the need for critical lateral alignment. The demands on the imprinting platform are thus reduced to providing coarse, uniaxial translation, allowing us to demonstrate a compact, portable module for fi ber-array imprinting. Finally, self-alignment uniquely accommodates non-planar molds, allowing us to employ a biological nanotemplate.Arrays of optical-fi bers were created using arrays of ...

Gorgi Kostovski and co‐workers demonstrate on the parallel nanoimprinting of multiple optical‐fiber facets on a novel imprinting platform. A passive, self‐alignment mechanism is used to relax the mechanical demands placed on the imprinting platform, allowing the fiber array to accommodate the non‐planarity of biological nanotemplates, as well as the demonstration of a compact, portable imprinting module. A resolution of better than 15 nm is demonstrated, and up to 40 optical‐fiber facets have been imprinted in parallel. This demonstration will enable the high‐throughput fabrication of fiber‐facet devices in a high‐resolution, cost‐effective and accessible way.

A new technique for parallel imprinting of multiple optical-fibre facets is presented. Resolution of better than 15nm is demonstrated and up to 40 optical-fibres have been imprinted in parallel. A compact, portable imprinting-module exploits self alignment to accommodate non-planar, biological molds.