Growth, anisotropic spectroscopy and laser operation of the monoclinic Nd:KGd(PO3)4 crystal

Type III KGd(PO3)4 and Nd:KGd(PO3)4 single crystals have been successfully grown. We have proved that these crystals have a wide transparency window closing at 160 nm in the UV region and extending to 4 μm in the IR region. We have determined that a slight rotation occurred for the dielectric frame in the 355–1064 nm range of wavelengths. We have measured the absorption in the 4I9/2 → 4F5/2 channel and the emission in the 4F3/2 → 4I11/2 channel. In addition to the three N p, N m, N g usual polarizations, a fourth spectroscopic parameter representing the framework rotation of the linear polarization imaginary part around the N p axis was needed for a full description. Lasing was obtained at 1052.4 nm in N p polarization (ordinary wave) for propagation in the N g − N m principal plane.