Efficient Energy Transfer and Enhanced Near-IR Emission in Cu+/Nd3+-Activated Aluminophosphate Glass

The development of photonic materials for efficient energy conversion and high-power solid-state lasers is currently pursued given the wide range of applicable technologies and the possibility to help meet global energy demands in laser fusion power plants. In this work, Cu+ ions successfully incorporated in aluminophosphate glass are recognized as near-ultraviolet (UV) sensitizers of Nd3+ ions resulting in remarkable near-infrared (IR) 4F3/2 → 4I11/2 emission at 1.06 μm. Optical absorption, solid-state 31P nuclear magnetic resonance, Raman, and photoluminescence spectroscopies characterizations are employed and assessment methods for material optical and structural properties are proposed. The spectroscopic data indicates an efficient (>50%) nonradiative energy transfer where the Cu+ ions first absorb photons broadly around 360 nm, and subsequently transfer the energy from the Stokes-shifted emitting states to resonant Nd3+ energy levels. Then, the Nd3+ electronic excited states decay and the upper lasing state 4F3/2 is populated, leading to enhanced near-IR emission. It is suggested that the physico-chemically robust Cu+/Nd3+ codoped aluminophosphate glass is a suitable candidate as solid-state laser material with enhanced pump range in the near-UV part of the spectrum and for solar spectral conversion in photovoltaic cells.