Open AccessTemperature-dependent diffuse reflectance spectroscopy of plasma-sprayed Cr-doped α-alumina using supercontinuum laser illumination and CO_2 laser heating
Author(s) -
Michael C. Brupbacher,
Dajie Zhang,
William M. Buchta,
Marc B. Airola,
David M. Brown,
Michael E. Thomas,
James B. Spicer
Publication year - 2017
Publication title -
applied optics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.668
H-Index - 197
eISSN - 2155-3165
pISSN - 1559-128X
DOI - 10.1364/ao.56.007618
Subject(s) - supercontinuum , materials science , laser , optics , spectroscopy , doping , plasma , diffuse reflectance infrared fourier transform , spectral line , optoelectronics , diffuse reflection , absorption spectroscopy , absorption (acoustics) , analytical chemistry (journal) , wavelength , chemistry , composite material , photocatalysis , biochemistry , physics , chromatography , quantum mechanics , astronomy , photonic crystal fiber , catalysis
This study presents results for the high-temperature (up to 1550 K) optical properties of polycrystalline Cr-doped α-alumina materials. Diffuse reflectance spectra in the wavelength range of 510-840 nm are presented as a function of temperature to illustrate changes to the optical behavior of these materials including a previously unreported thermally activated splitting of the U-band absorption (A 2 4→T 2 4) in octahedrally coordinated Cr 3+ . Measurements were made using a unique laser-based approach for high-temperature solid-state spectroscopy, involving front-side supercontinuum laser illumination and back-side CO 2 laser heating. This approach required development of samples that could withstand related thermal stresses, and measurements were made on plasma-sprayed, Cr-doped α-alumina monoliths. Measured spectra are interpreted, in part, using published optical spectra for ruby; agreement between results here with those obtained using more traditional methods serves to validate the measurement methods used for this work.