2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/208226We present a mathematical formalism describing the propagation of a completely general electromagnetic wave in a birefringent medium. Analytic formulas for the refraction and reflection from a plane interface are obtained. As a particular example, a Bessel beam impinging at an arbitrary angle is analyzed in detail. Some numerical results showing the formation and destruction of optical vortices are presented.18 pages, 6 figuresOpticstext