Conical refraction: an experimental introduction

Abstract

We outline some general properties of the conerefracted (CR) beam - a beam passed along an optic axis of biaxial crystal. The intensity of the incident beam is assumed to have a propagation <i>z</i>-axis of cylindrical symmetry and a symmetry plane <i>z</i> = 0. The CR beam also has a symmetry plane <i>Z</i> = 0 and two kinds of axial symmetries with common <i>Z</i>-axis; besides, it possesses two focal planes <i>Z</i> = &plusmn;<i>Z</i>_F. The familiar light ring is best resolved at <i>Z</i> = 0. Some of the beam transformation rules can be "seen" as known from the geometrical or Gaussian optics. We present for the first time experiments with two consecutive crystal elements. In this case the exit beam splits in two CR beams and their parameterization is given by explicit formulas. The experimentally deduced rules are simple but not trivial.