Spatial coherence effects in second-harmonic generation of scalar light fields. (18th February 2021)

• Record Type: Journal Article
• Authors: Pesonen, Henri; Halder, Atri; Huusko, Juha-Matti; Friberg, Ari T; Setälä, Tero; Turunen, Jari
• Is Part Of: Journal of optics. Volume 23:Number 3(2021)
• Publication Date: 2021-02-18
• Subjects: coherence theory -- non-linear optics -- second-harmonic generation; Optics -- Periodicals; 535.05
• DOI: 10.1088/2040-8986/abd887
• Languages: English
• ISSNs: 2040-8978

Abstract

Abstract: We consider the spectral spatial coherence characteristics of scalar light fields in second-harmonic generation in an optically non-linear medium. Specifically, we take the fundamental-frequency (incident) field to be a Gaussian Schell-model (GSM) beam with variable peak spectral density and different coherence properties. We show that with increasing intensity the overall degree of coherence of both the fundamental and the second-harmonic field in general decreases on passage through the non-linear medium. In addition, the spectral density distributions and the two-point degree of coherence may, for both beams, deviate significantly from those of the GSM, especially at high intensities. Propagation in the non-linear medium is numerically analyzed with the Runge–Kutta and the beam-propagation methods, of which the latter is found to be considerably faster. The results of this work provide means to synthesize, via non-linear material interaction, random optical beams with desired coherence characteristics.