By Josh Perry, Editor
[email protected]

Researchers from the University of Leeds (U.K.) have reported on a laser-assisted study of glass, made of sodium, zinc, and tellurium, which has been doped with the rare-earth element erbium and could be used to improve telecommunications technology.

Microscopy image of ultrafast laser ablation craters in tellurite-based glass.
(Thomas Mann, Leeds, U.K.)

According to a report from the American Institute of Physics (AIP), scientists are studying planar waveguides to avoid lengthy optical fibers and potentially miniaturize telecom devices. It added, “Erbium-doped waveguide amplifiers have garnered attention because electronic transition for erbium occurs at the same wavelength, 1.5 microns, that is a standard in telecommunications technologies.”

Researchers used ultrafast laser plasma doping. They blasted the surface of the erbium-doped glass with high-intensity lasers, which resulted in tiny craters, and produced a thin film from the ejected material.

“Their measurements during the film formation process focused on the ablation threshold of the glass,” the article explained. “This quantity describes the minimum energy required to separate atoms or molecules by intense laser irradiation. The investigators determined how the ablation threshold in their system was affected by the radius of the laser beam, the number of laser pulses and the concentration of the erbium ion dopant.”

They discovered that the ablation threshold was not dependent on the low doping concentration of erbium ions that would be needed to engineer a device. They also believe that this study could be applied to other dielectric materials, not just erbium.

“The investigators also looked at the shape and characteristics of the tiny craters blasted into the glass,” the report added. “Understanding the morphology of craters produced during the fabrication process is important for controlling properties such as the porosity, the surface area, and the ability of the material to scatter or absorb light.”

The research was recently published in the Journal of Applied Physics. The abstract stated:

"We report the femtosecond laser (100 fs, 800 nm) ablation properties of Er³⁺ ion doped zinc-sodium tellurite glass. Ablation thresholds in dependence of the beam radius (13.9 and 32.0 μm), pulse number, and Er³⁺ ion dopant concentration have been determined.

“The ablation rate and crater profile depended on the applied fluence.”