Figure 7

(a) Photoluminescence emission spectra of CYO:Ho³⁺ (0.05, 1.0, 1.5, 2.0, 2.5, 3 mol%) (inset: effect on PL emission intensity with concentration of Ho³⁺ ions) (b) Emission spectra of CYO:2.0 Ho³⁺,xEu³⁺ (x = 0, 1, 3, 5, 7, 9 mol%) at λ_ex = 448 nm.