Laser-Induced Deposition of Single-Walled Carbon Nanotubes in Suspended Core Optical Fibers

TL;DR

This paper demonstrates the first laser-driven deposition of single-walled carbon nanotubes inside suspended core optical fibers, enabling new applications in fiber sensors, lasers, and biomedical devices.

Contribution

It introduces a novel method for depositing CNTs inside fibers using laser heating, expanding fabrication capabilities for fiber-based nanodevices.

Findings

CNTs deposited successfully inside fibers with controlled thickness

Deposition thickness varies with fiber type and laser exposure time

Potential for advanced fiber sensor and device fabrication

Abstract

We experimentally demonstrate laser-driven deposition of single-walled carbon nanotubes (CNTs) in suspended core fibers (SCFs) for the first time. Two samples for each SCF type with three (SCF1) and four (SCF2) air holes are individually inserted in a syringe loaded with a 0.5 mL solution of CNTs dispersed in methanol, and a high-power laser at 980 nm is injected into the fibers during distinct periods: SCF1 (20 and 30 minutes), SCF2 (5 and 10 minutes). The CNT solution thermally expands, accelerating and depositing nanotubes on the fiber tip. The material and dimensions of the CNTs deposited on the SCFs' cross-section are characterized, revealing nanotube bundles increasing in thickness from the fiber core to the bridges and inside the holes. The average maximum CNT thickness widening the bridge edges is, respectively, for SCF1 (2.8 and 2 microns) and SCF2 (1.7 and 1.3 microns). These achievements are significant for nanoparticle deposition and fabrication of microscale devices on tips and inside specialty and hollow fibers, enabling innovative fiber sensors, mode-locked fiber lasers, in-fiber acousto-optic modulators, and broadband photoacoustic transmitters for imaging and neurostimulation.