Nonlinear Optical Response of Chinese Teas Probed by Spatial Self-Phase Modulation

Abstract

Chinese tea is the most highly consumed beverage globally. Its different types exhibit a strong nonlinear optical response as probed previously by Z-scan technique at various time scales. In this work, infusions of commercially available black, green, and white Chinese teas, prepared by running one cycle of a Soxhlet extraction, were studied by spatial self-phase modulation of a CW laser; each sample was found to have a different nonlinear refractive index n 2 , which can be used to distinguish these teas.

Non-linear optical response as a food authentication: Investigation of non- linear optical properties of edible oils by Spatial Self-Phase Modulation (SSPM) method

“…Due to their wide range of applications in optical and photonic devices, such as optical limiting (Marbello O et al 2020), optical switching (Henari and Cassidy 2012), and optical communication (Wong et al 1991), most researchers are currently concentrating on exploring materials with high non-linear optical responses. On the other hand, studying non-linear optical properties ensures sample authenticity and purity (Ribeiro et al 2019) and sample differentiation (de Souza et al 2020). Several methods are currently available to determine the non-linear characteristics of materials, including elliptical rotation, the measurement of beam distortion, interference of two or four waves, Z-Scan, and Spatial Self Phase Modulation (SSPM) (Li 2017).…”