4F3/2→4I9/2 and 4F3/2→4I13/2 laser operations with a Nd:GdTaO4 crystal

Abstract

This study investigated the laser performance of a Nd:GdTaO4 crystal for the 4F3/2→4I9/2 and 4F3/2→4I13/2 transitions at 928 nm and 1328 nm, respectively. A 5-mm-thick, 1.4 at.% Nd:GdTaO4 crystal was used in the experiments, under a pump at 879 nm, directly into the 4F3/2 emitting level. At a 10 Hz pump repetition rate, the maximum pulse energy at 928 nm reached 35.7 mJ, with an optical-to-optical efficiency of ~19.3%. When the pump repetition rate increased to 100 Hz, the laser pulse energy decreased to 13.5 mJ; the laser beam was characterised by M2 factors of Mx2 = 1.4 and My2 = 1.8 for the Ox and Oy axis, respectively. The Nd:GdTaO4 crystal yielded laser pulses at 1328 nm with a maximum energy of 9.7 mJ for operation at 10 Hz repetition rate; the overall optical-to-optical efficiency amounted to ~5.2%. Increasing the pump repetition rate to 100 Hz reduced the laser pulse energy to 5.8 mJ; the laser beam M2 factors were Mx2 = 1.2 and My2 = 1.4.