Polarization singularities in second harmonic beam generated from the surface of a medium with spatial dispersion of nonlinear response

• Published in: Journal of optics (2010) 2012-05, Vol.14 (5), p.55202-1-10
• Main Authors: Makarov, V A, Perezhogin, I A, Portavkin, N N
• Format: Article
• Language: English
• Subjects: Approximation; Beams (radiation); Broken symmetry; Dispersions; elliptically polarized light; Harmonics; Mathematical analysis; Polarization; polarization singularity; Singularities; spatial dispersion; surface second harmonic generation
• ISSN: 2040-8978; 0150-536X; 2040-8986
• DOI: 10.1088/2040-8978/14/5/055202

The conditions of appearance and the behavior of C-point-polarization singularities in the second harmonic beam reflected from the surface of an isotropic chiral medium with spatial dispersion of nonlinearity in the case of oblique incidence of the elliptically polarized Gaussian profile fundamental beam is considered. Within the framework of the paraxial approximation (first order approximation on the beam divergence angle) it is shown that for any medium parameters there is a polarization state of the incident beam which provides the appearance of the C-point in the center of the transverse section of second harmonic beam. Small variations of this polarization state with a constant value of the angle of incidence or small variations of the angle of incidence with a constant polarization state both result in a shift of the C-point out of the center of the signal beam. The beam structure transformation and symmetry breaking is studied when proceeding from the normal incidence geometry to the oblique one.