Effects of the excitation wavelength and temperature on the zero-phonon emission lineofCr:YAG.

Abstract

In this work, a detailed study was conducted of the temperature and excitation wavelength-dependent photoluminescence (PL) spectra of the chromium-doped yttrium aluminum garnet (Cr:YAG) transparent ceramic. Focusing on the two sets of zero-phonon lines (ZPLs) of the 2 E→4 A 2 transition in this material, the PL spectra are discovered to evolve significantly with respect to temperature and be highly dependent on the excitation wavelength. Compared to the continuous variation behavior with temperature, an increase in the excitation wavelength leads to a blueshift of the peak position within the regions of 450nm to 465nm, 465nm to 490nm, and 490nm to 500nm, and a sharp change in the PL position at the excitation wavelengths of 465nm and 490nm. The electron-phonon coupling (EPC) effect is believed to be more sensitive to the excitation wavelength. Different excitation wavelengths involve different electronic levels participating in the light emission processes, which explains the evolution behavior of the PL peak position with respect to the excitation wavelength. Moreover, the emergence of weak peaks next to the ZPLs at particular temperatures and excitation wavelengths is also observed. This work compares the influence of the temperature and excitation wavelength to the PL properties of the Cr:YAG transparent ceramic, which promotes an advanced understanding of the luminescence behavior of the Cr:YAG transparent ceramics.