  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 ebeam 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 operation 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 \b{eta} eff 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.
