Nonlinear effects and other optical phenomena would become nontrivial at greater optical intensities. This article discusses the annealing effect on the linear and third-order nonlinear optical response of Physical Vapour Deposited (PVD), naturally oxidized CuxO thin films that are thermally annealed under N2 ambience at different temperatures. In particular, the nonlinear absorption (NLA) coefficient, \(\beta\) , nonlinear refractive (NLR) index, \(n_{2}\) of naturally oxidized and thermally treated CuxO thin film on a quartz glass substrate were determined using continuous-wave (CW) laser Z-scan techniques at 637 nm wavelength. The optimal third-order nonlinear susceptibility, \({\upchi }^{\left( 3 \right)}\) of the prepared CuxO thin film was measured to be 4.19 × 10⁻2 esu at an annealing temperature of 450 °C, corresponding to the lowest energy bandgap of 2.12 eV. In addition, the exploration of crystal, structural, morphological, topological, and compositional characteristics ascertained the good quality growth of prepared CuxO thin films. These findings unambiguously establish that the thermally treated absorption of prepared CuxO thin films are pivotal for advancing integrated photonics platforms, particularly in nonlinear as well as quantum photonics applications.
