Near-infrared to green photon upconversion in Mn2+ and Yb3+ doped lattices

Abstract Yb 3+ excitation in the near-infrared around 1 μm leads to green Mn 2+ 4 T 1  →  6 A 1 luminescence in CaZnF 4 :Mn 2+ ; Yb 3+ , Zn 2 SiO 4 :Mn 2+ ; Yb 3+ and SrZnCl 4 :Mn 2+ ; Yb 3+ at 15 K. In the former two compounds the green upconversion (UC) luminescence is visible by eye up to room temperature. In Cs 3 MnBr 5 :Mn 2+ ; Yb 3+ no UC luminescence is observed. The UC mechanism consists of a sequence of ground-state absorption and excited-state absorption steps. The UC efficiency at 15 K is of the order of 1% for laser excitation with 130 mW ( f =53 mm focusing lens).