Fluorescence and laser‐emission cross sections in NaNdP4O12

As a solid‐state laser material, NaNdP4O12 (NNP) single crystals were grown by the top‐seeding Kyropoulos method. It belongs to the monoclinic system with space group P21/c‐C52h, and the Nd content is 4.24×1021 cm−3. Fluorescence was examined at room temperature and at 77 °K. The lifetime of the 4F3/2 level was measured to be 110±10 μs. A cw laser action was confirmed at room temperature. The laser emission was linearly polarized along the c axis. The effective emission cross section was measured to be σc=2.1×10−19 cm2.