Optical properties of Nd3+ and Yb3+-doped AgM(IO3)4 metal iodates: transparent host matrices for mid-IR lasers and nonlinear materials

Abstract

Nine new isomorphic iodate compounds NaM(IO₃)₄ with M = Y, Nd, Gd and AgM′(IO₃)₄ with M′ = Y, La, Nd, Eu, Gd, Bi have been synthesized either by evaporation of concentrated nitric acid solution or by hydrothermal synthesis. They crystallize in the monoclinic acentric Cc space group. Typical unit cell parameters for AgY(IO₃)₄ are a = 31.277(3) Å, b = 5.547(1) Å, c = 12.556(2) Å, β = 91.11(2)°, V = 2178.0(6) ų and Z = 8. Crystal structures have been solved on single crystals for NaY(IO₃)₄, AgY(IO₃)₄, AgLa(IO₃)₄, AgGd(IO₃)₄ and AgBi(IO₃)₄ and on powder for NaNd(IO₃)₄, NaGd(IO₃)₄, AgEu(IO₃)₄ and AgGd(IO₃)₄. They are thermally stable up to 550 °C for NaY(IO₃)₄, 430 °C for AgY(IO₃)₄, 500 °C for AgLa(IO₃)₄ and 490 °C for AgBi(IO₃)₄. The crystal structure reveals a two-dimensional layered network. The sheets are connected together by I⋯O interactions. All these metal iodates generate second harmonics and are transparent up to 12 μm. So they are interesting as potential laser matrices in the mid and beginning of the far-infrared. The properties of Nd³⁺ and Yb³⁺-doped AgGd(IO₃)₄ and of Nd³⁺-doped AgLa(IO₃)₄ have been studied.