Quantum efficiency measurements on Nd-doped glasses for solar pumped lasers

Nd-doped SiO2–B2O3–Na2O–Al2O3–CaO–ZrO2 glasses were prepared and optical properties such as absorption, lifetime and quantum efficiencies (QEs) of the emission were characterized. QE measurement system with natural sunlight as an excitation source was constructed. The radiative QE (ηr) obtained from the lifetime by Judd–Ofelt analysis, directly measured QEs using natural sunlight (ηns), simulated sunlight (ηss) and an 800 nm laser (η800) were measured and were compared with each other. The QE measurements suggest that the reduction of parasitic absorption by the host glass could be a more important factor for solar pumped lasers than for laser diode pumped lasers in order to increase the efficiency.