Table 3. Fluorescence lifetime of Gd_0.99Er_0.01AlO₃ and Gd_0.99Er_0.01Al_0.995Cr_0.05O₃ samples, monitored at Er³⁺ emission wavelengths of λ_em = 542 nm and λ_em = 697 nm under λ_ex = 377 nm.

Samples	Gd0.99Er0.01AlO3		Gd0.99Er0.01Al0.995Cr0.05O3
The recorded wavelength	697 nm	542 nm	697 nm	542 nm
	Double-exponential	Mono-exponential	Double-exponential	Double-exponential
	2.61–1.18	0.13	—	—
	—	—	1.69–10.77	0.13–0.03