Saturable absorption and self-focusing properties of copper molybdate with flower structure

Copper molybdate (CuMoO₄) nanomaterial was synthesized by an ultrasonic method. The successful synthesis of CuMoO₄ was testified by Raman spectrum. The scanning electron microscopy (SEM) analysis reveals that the CuMoO₄ exhibits irregular flower structure. The average thickness of each petal is about 30 nm. The CuMoO₄ was dispersed into methyl methacrylate (MMA) to fabricate CuMoO₄/PMMA organic glass with different amounts. The band gap (E_g) of CuMoO₄/PMMA is about 2.28 eV obtained from the conversion of the ultraviolet-visible (UV-Vis) absorption spectra. The nonlinear absorption (NLA) and nonlinear refraction (NLR) of CuMoO₄/PMMA organic glass were measured by the Z-scan technique. The CuMoO₄/PMMA organic glass exhibits saturable absorption (SA) and self-focusing effect. The saturable light intensity, NLA coefficient and NLR coefficient are I_s = 6.8 MW cm⁻², β = –109 cm GW⁻¹ and γ = 2.43 × 10⁻⁶ cm² MW⁻¹ at the incident energy of 20 μJ, respectively. At the same incident energy of 20 μJ, the I_s value of CuMoO₄/PMMA is about half that of NiMoO₄/PMMA. Therefore, the CuMoO₄ nanomaterial is easier to exhibit saturable absorption (SA). It is found that T < 1, W> 1 by analyzing the figures of merit for CuMoO₄/PMMA. Therefore, the NLR of CuMoO₄/PMMA is dominate. The results show that CuMoO₄ nanomaterial has potential applications in lasers and optical switches.