Eco-friendly virgin grape seed oil as a strong thermo-optic nonlinear medium for all-optical modulation and switching

• The nonlinear optical behavior of virgin grape seed oil (VGSO) was studied. • Employed the spatial self-phase modulation method with a continuous laser at 405 nm. • The VGSO sample exhibits a significant nonlinear optical response. • Demonstrating phase modulation of a weak laser via the SXPM technique. • The VGSO sample enables all-optical switching with a high-efficiency ON/OFF function. A comprehensive understanding of the nonlinear optical characteristics of materials is essential for the development of nonlinear optical applications and the advancement of all-optical devices. Nonlinear phase modulation is emerging as an attractive and powerful research method to investigate optical nonlinearities, light modulation processes, and all-optical switching. This work aims to investigate the nonlinear optical behavior of virgin grape seed oil (VGSO) by observing the spatial self-phase modulation (SSPM) phenomenon and demonstrating the applications of the light-modulation-light process and all-optical switching using the spatial cross-phase modulation (SXPM) technique. The nonlinear refractive index ( n 2 ) and the thermo-optical coefficient ( dn / d T ) were computed to be 2.87 × 10 - 5 cm 2 / W and 7.5 × 10 - 3 K - 1 , respectively, employing a 405 n m continuous-wave laser in the SSPM geometry. Moreover, the modulation of a weak 633 n m He-Ne laser through the SXPM technique was achieved with using a high-intensity 405 n m diode laser, which enabled ON-OFF switching as an all-optical switch. These results introduce grape seed oil (VGSO) as a viable reference for the optical nonlinearity of vegetable oils, providing an environmentally friendly and cost-effective alternative to conventional materials to achieve high-efficiency light modulation and the future advancement of all-optical devices.