⁴F_3/2→⁴I_9/2 and ⁴F_3/2→⁴I_13/2 laser operations with a Nd:GdTaO₄ crystal

This study investigated the laser performance of a Nd:GdTaO₄ crystal for the ⁴F_3/2→⁴I_9/2 and ⁴F_3/2→⁴I_13/2 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 ⁴F_3/2 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 M_x² = 1.4 and M_y² = 1.8 for the O_x and O_y 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 M_x² = 1.2 and M_y² = 1.4.