Abordagem clássica da interação luz-matéria para descrever o processo de geração de segundo-harmônico

Abstract

For a long time, the study of light-matter interaction was limited to linear optical phenomena (those in which polarization is directly proportional to the electric field of the incident light). However, in the mid-20th century, with the development of laser light (high intensity light) by Theodore Maiman and later with the experiments of Peter A. Franken, this changed. Franken observed in one of his experiments that when a radiation source with frequency (ω) and wavelength (λ) was incident on a crystal, the radiation that emerged from it was composed of two different frequencies, one equal to the incident beam (ω) and the other with twice the frequency (2ω), which corresponds to half the wavelength (λ/2). This phenomenon was unexpected, given that it does not satisfy the linearity of the optical phenomena known until then. This phenomenon was called Second Harmonic Generation (SGH) and marked the beginning of the study of nonlinear optics, which we will study in this work.