Non-linear optical response of edible oils by means of the Z-scan technique

Abstract

Oils of vegetable origin are classified as organic compounds, which have become the object of study in the field of photonics and non-linear optics, because they have a characteristic chemical bond with the presence of delocalized electrons, which gives them a high non-linear response. In the food industry, non-destructive or invasive studies are required to establish the quality and conservation indices of the chemical, physical and nutritional properties of edible products. The non-linear optic response of different oils of vegetable origin was evaluated: extra virgin olive oil, extra virgin sesame oil, extra refined linseed oil and virgin avocado oil using the Z-scan technique. The absorption and transmission spectra were taken to establish the coefficient of linear absorption of the sample as a function of the wavelength. For each compound, the variations of the nonlinear optical properties were analyzed as a function of the excitation power, using the closed cell and open cell configurations; where the third-order electrical susceptibility (χ3), the non-linear refraction index (η2) and the non-linear absorption coefficient (β) were determined. Subsequently, a comparison of the non-linear response was made according to the type of oil and the degree of refinement. It was found that extra virgin olive oil and virgin avocado oil presented a better non-linear response at low laser power as a consequence of the low thermal influence, which makes them possible candidates in the development of photonic devices.