Optical nonlinearity and laser protection potential of transition and rare earth doped YCrO4 nanoparticles

Abstract

This study investigates the nonlinear optical (NLO) properties of YCrO₄ (YC), YCrO₄:Zn (9 mol%) (YCZ), YCrO₄:Ni (9 mol%) (YCN), YCrO₄:Eu (9 mol%) (YCE), and YCrO₄:Tb (9 mol%) (YCT) NPs. These NPs are synthesized by Aloe vera gel extract mediated solution combustion method. The X-ray diffraction patterns of YCrO₄ confirm the formation of tetragonal phase with the space group I 14₁/amd. No other impurity related peaks were observed even after doping with transition/rare earth metal ions except the variation in intensity. Lattice distortion in the host lattice due to the addition of dopants leads to slight shifting of Bragg peaks towards lower angle side. The direct optical band gap of YC, YCZ, YCN, YCE and YCT were tuned to 3.08, 3.05, 2.96, 2.86 and 2.75 eV respectively. The nonlinear absorption coefficient and optical limiting behavior were analyzed using the Z-scan technique under high-intensity laser irradiation. The results reveal significant variations in the nonlinear absorption coefficient among the samples, indicating the influence of dopants on the material’s NLO performance. Among them, YCN exhibited the highest nonlinear absorption coefficient (14 m/W), demonstrating its strong reverse saturable absorption (RSA) characteristics. The optical limiting thresholds were also evaluated, showing that YCN had the lowest threshold (2.02 W/m²), making it a promising candidate for laser protection applications. These findings suggest that doping YCrO₄ with specific elements such as Ni${}^{2+}$ enhances its nonlinear optical response, making it suitable for advanced photonic and optoelectronic applications.