Nonlinear absorption, refraction and optical limiting properties of cobalt molybdate microcrystals

Abstract

Cobalt molybdate (CoMoO4) microcrystal was synthesized by a hydrothermal method. The CoMoO4 microcrystal was dispersed in methyl methacrylate (MMA) that was polymerized to polymethyl methacrylate (PMMA) to prepare CoMoO4/PMMA organic glass. The successful synthesis of CoMoO4 was verified by Raman spectroscopy. The CoMoO4 microcrystal was characterized by scanning electron microscopy (SEM). The results indicate that the CoMoO4 microcrystal is microrod. The diameter and length of the sample are about 0.5–3 μm and 2–20 μm. The band gap of CoMoO4/PMMA is about 3.5 eV. The nonlinear absorption (NLA) and refraction properties of CoMoO4/PMMA organic glasses were investigated for the first time by a Z-scan technique. The laser pulse energy is 7–20 μJ. The results indicate that CoMoO4/PMMA organic glasses exhibit good reverse saturable absorption (RSA) and self-defocusing effects. NLA and refraction coefficients are β = 68 cm GW−1 and γ = −1.4 × 10−4 cm2 GW−1 at the laser pulse energy of 20 μJ, respectively. The enhanced RSA and self-defocusing effects make the CoMoO4/PMMA organic glasses exhibit excellent optical limiting (OL) performance. The nonlinear absorption, refraction and OL properties of CoMoO4/PMMA organic glasses can be controlled by adjusting the laser pulse energy and the amount of CoMoO4 in PMMA.