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