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

Abstract 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 Ω 2 is solved to be 8.04 × 10 − 20 cm 2 , 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 1 D 2 → 3 H 4 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 1 D 2 level are identified to be 164.3 μs and 87.7%, respectively, and the quantum yield (QY) of 1 D 2 → 3 H 4 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.