rt-TDDFT modeling of thermal emission by laser-heated glasses

TL;DR

This paper uses rt-TDDFT modeling to analyze the infrared emission spectra of laser-heated glass layers, helping to improve the accuracy of thermal measurements in laser processing.

Contribution

It introduces a real-time TDDFT approach to simulate thermal emission from laser-heated glasses, accounting for vibrational effects on spectra.

Findings

rt-TDDFT can accurately predict emissivity of hot glass layers.

Spectral deviations from black-body radiation are explained by vibrational structures.

Method improves interpretation of thermal camera measurements.

Abstract

In the laser processing of glass, a ~50-1000 $\mu$m-thick layer of glass is heated to a high temperature by the laser beam. Due to the shallow depth of this hot layer, the infrared emission and absorption spectra may deviate from the black-body spectra and can be influenced by the vibrational structure of the material. Real-time time-dependent density functional theory (rt-TDDFT) modeling of the thermal radiation by such hot layers allows us to calculate the emissivity and thus to evaluate the reliability of the measurements conducted with thermal cameras at specific wavelengths.