Optical nonlinearity in CuO thin films for the generation of hollow Gaussian beam

Abstract During the present work, thin films of Copper (Cu) were deposited onto glass substrates using the electron beam deposition technique. The thin films were exposed to heat treatments at varying temperatures of 400 °C, 500 °C, and 600 °C. The films were analyzed to determine their structural, morphological, and optical characteristics using different techniques such as x-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), and UV-visible spectroscopy respectively. FESEM revealed an increase in particle agglomeration with higher temperatures. EDX(Energy dispersive x-ray spectroscopy) confirmed the presence of only copper (Cu) and oxygen (O), indicating impurity-free films. The absorbance properties were analyzed using UV-visible spectroscopy. As the oxidation temperature increases, the optical energy bandgap of prepared thin films changes. The nonlinear optical properties of deposited thin films, such as non-linear third-order susceptibility ( χ 3 ), nonlinear refractive index(n 2 ), and absorption coefficient( α ) were analyzed using the Z-scan method at 532 nm. The χ 3 values ranged from <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>2.71</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>5</mml:mn> </mml:mrow> </mml:msup> </mml:math> e.s.u. to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>1.19</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>5</mml:mn> </mml:mrow> </mml:msup> </mml:math> e.s.u. The prepared thin films exhibited a reduced optical limiting threshold of 1.3 KJ cm −2 , demonstrating their strong potential for optical limiting applications