Dy^{3 +} doped sodium-magnesium-aluminum-phosphate glasses for greenish-yellow waveguide light sources

Intense greenish-yellow emission near the hemoglobin absorption peak at 577 nm was observed in Dy^{3 +} doped sodium-magnesium-aluminum-phosphate (NMAP) glasses under UV excitation. The Judd-Ofelt intensity parameters and the integrated fluorescence intensity ratio between ⁴F_9/2 → ⁶H_13/2 (yellow) and ⁴F_9/2 → ⁶H_15/2 (blue) imply a strong asymmetrical and covalent environment around Dy^{3 +} in the phosphate glasses. The fluorescence branching ratio and the stimulated emission cross-section of the ⁴F_9/2 → ⁶H_13/2 transition were identified to be 65.9% and 25.65 × 10^{- 22} cm², respectively, confirming the efficiency of the visible fluorescence emission. Channel waveguide was fabricated successfully by K⁺-Na⁺ ion-exchange method with mode field diameter of 20.5 μm in the horizontal direction and 8.7 μm in the vertical direction. The results demonstrate that Dy^{3 +} doped NMAP glasses are promising to develop waveguide light sources for thrombolysis. © 2014 Elsevier B.V.