Quantum efficiency of Nd3+-doped glasses under sunlight excitation

The internal quantum efficiencies under sunlight and laser excitation were measured directly by an integrating sphere method for tellurite, borosilicate and fluoride glasses. The radiative quantum efficiency was also obtained by Judd–Ofelt analysis. The radiative quantum efficiency was almost 100% for tellurite and fluoride glasses and 50% for borosilicate glasses. The quantum efficiency under laser excitation was 86%, 34% and 88% for tellurite, borosilicate and fluoride glasses at a low Nd3+ content and decreased by concentration quenching. The quantum efficiency under sunlight excitation was up to 33%, 21% and 70% for tellurite, borosilicate and fluoride glasses. Nd3+-doped fluoride glass is a promising candidate for solar pumped laser applications since it has the high quantum efficiency under sunlight excitation.