Super-quadratic Upconversion Luminescence of Nd3+ Ions in GdVO4 and LaSc3(BO3)4 Laser Crystals

We measured upconversion (visible) and direct (infrared) luminescence decay of Nd3+-doped laser materials under equivalent pump conditions. We found a strongly super-quadratic instead of the expected quadratic dependence between these curves. Calculations partially explain experiments. © 2019 The Author(s)