One-step deposition and in-situ reduction of graphene oxide in glass microcapillaries and application to photonics

TL;DR

This paper presents a simple method for coating glass microcapillaries with graphene oxide, enabling in-situ reduction and demonstrating applications in photonics such as fiber polarizers and mode lockers for pulsed lasers.

Contribution

Introduces a one-step, surface-functionalization-free technique for coating and reducing graphene oxide inside glass microcapillaries for photonic device applications.

Findings

Continuous GO films along tens of centimeters in microcapillaries.

Thermal reduction decreases defect concentration in GO films.

Reduced GO-coated fibers produce shorter laser pulses.

Abstract

Films of graphene oxide (GO) were produced on the inner walls of glass microcapillaries via insertion of a GO water suspension followed by quick drying with a hot finger (no previous surface functionalization required). Individual capillaries from an array could also be selectively GO coated. Raman hyperspectral images revealed the films to be continuous along tens of centimeters. Furthermore, the films could be thermally reduced through an annealing process, which also decreased the concentration of defects. As a proof of principle application, the microcapillaries of photonic crystal fibers were covered with a GO film, leading to the demonstration of fiber polarizers and mode lockers for pulsed fiber lasers. A comparison between GO- and reduced GO-coated fibers revealed that shorter pulses are obtained with the latter.