Methodical engineering of defects in MnXZn1-X O(x = 0.03, and 0.05) nanostructures by electron beam for nonlinear optical applications: A new insight

Abstract

A series of MnxZn1-xO (x = 0.03, 0.05) nanostructures have been grown via the solution based chemical spray pyrolysis technique. Electron beam induced modifications on structural, linear and nonlinear optical and surface morphological properties have been studied and elaborated. GXRD (glancing angle X-ray diffraction) patterns show sharp diffraction peaks matching with the hexagonal wurtzite structure of ZnO thin films. The upsurge in e-beam dosage resulted in the shifting of XRD peaks (101) and (002) towards lower angle side, and increase in FWHM value. Gaussian deconvolution on PL spectra reveals the quenching of defect centers, implying the role of electron beam irradiation regulating luminescence and defect centers in the nanostructures. Irradiation induced spatial confinement and phonon localization effects have been observed in the films via micro Raman studies. The later are evident from spectral peak shifts and broadening. Detailed investigations on the effect of electron beam irradiation on third order nonlinear optical properties under continuous and pulsed mode of laser op-eration regimes are deliberated. Third order absorptive nonlinearity of the nanostructures evaluated using the open aperture Z-scan technique in both continuous and pulsed laser regimes shows strong nonlinear absorption coefficient βeff of the order 10 -4 cm/W confirming their suitability for passive optical limiting applications under intense radiation environments. Laser induced third harmonic generation (LITHG) experiment results supports the significant variation in nonlinearities upon electron beam irradiation, and the effect can be utilized for frequency conversion mechanisms in high power laser sources and UV light emitters.

Au/ZnO Hybrid Nanostructures on Electrospun Polymeric Mats for Improved Photocatalytic Degradation of Organic Pollutants

“…the Au NPs in the ZnO/Au hybrid systems. In fact, in the Raman spectrum of PMMA/ZnO-Au1 (Figure 4b), additional peaks appeared at 450 cm −1 and 560 cm −1 , which were respectively assigned to the E2 high and A1(LO) modes of the ZnO, proving the non-resonant surface enhanced Raman scattering of the ZnO optical modes in the proximity of Au NPs [37,41,42]. The Raman spectra of the PMMA/ZnO-Au3 and PMMA/ZnO-Au6 ( Figure S7) show analogue enhancement of the Raman scattering of the ZnO optical modes.…”

Third-harmonic optical process in Zn:NiO thin films under the influence of femtosecond and continuous wave laser excitation

“…Additionally, these excited electrons can transition to defect states, serving as intermediate levels within the bandgap. Electrons in the defect state can further undergo excitation to higher levels, contributing to the ESA mechanism, thereby amplifying the RSA in the films [45]. Furthermore, the increased nonlinear absorption observed in Zn-doped NiO films, in contrast to pure NiO films, could be explained by Zn ions within the NiO matrices, leading to FCA [46].…”