High-aluminum phosphate glasses for single-mode waveguide-typed red light source

High-aluminum phosphate (HAP) glasses with excellent chemical durability have been fabricated and investigated for thermal ion-exchanged optical waveguide. With the content adjustment, the glass constituents turn into high-aluminum area and the glass stability has been appropriately improved with more Al^{3 +} ions cross-linked with phosphate chains, resulting in a restriction of ion-exchange rate. Consequently, stable single-mode slab waveguide operating in visible region was fabricated on Pr^{3 +} doped HAP glass substrates by K⁺-Na⁺ ion-exchange. For Pr^{3 +} doped HAP glasses, Judd-Ofelt intensity parameter Ω₂ is solved to be 8.04 × 10^{- 20} cm², implying a strong asymmetrical and covalent environment around Pr^{3 +} in the optical glasses. Using the Ω_t values, spontaneous transition probability (A_rad) and branching ratio (β) of ¹D₂ → ³H₄ emission are calculated to be 824.3 s^{- 1} and 13.54%, respectively, indicating that the transition emission is dominant in visible region. The radiative lifetime (τ_rad) and the quantum efficiency (η_q) of ¹D₂ level are identified to be 164.3 μs and 87.7%, respectively, and the quantum yield (QY) of ¹D₂ → ³H₄ transition emission is derived to be 2.3%. These results demonstrate that Pr^{3 +} doped HAP glasses are a promising substrate in developing high-density waveguide-typed red light source, which contains attractive potential applications in medical treatment and illumination.