Mn-doped Ho2O3 nanoparticles: Structural, linear and nonlinear optical property enhancements for advanced optoelectronic applications

We report on the structural, linear and nonlinear optical properties of Mn-doped Ho_2-xMn_xO₃ (x = 0.00, 0.05, and 0.10) powders prepared by sol-gel technique. Investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectra and UV–visible spectroscopy measurements. The Rietveld refinements program showed that all the compounds crystallize in the bixbyite crystal structure. As the Mn content increases, the bandgap energy exhibits a lowering from 3.2691 eV to 2.7470 eV as the size of the nanoparticle increases from 32.10 to 48.89 nm. Additionally, we conducted an analysis relating Urbach energy, refractive index, dielectric coefficient, and optical conductivity to the Mn content within the structure. Furthermore, we explored nonlinear optical parameters, including oscillator energy, dispersion energy, static refractive index, and third-order nonlinear optical susceptibility, all as functions of Mn content. The bandgap energy and the effective oscillator energy decreased while The Urbach energy, the dispersion energy, the refractive index and the dielectric constant increased with increasing Mn %. Based on these linear and nonlinear optical properties, Ho_2-xMn_xO₃ is presented as a good choice and a promising candidate for advanced photonic and optoelectronic applications.