Fig. 1: 3D optical polarisation texture.
A light field with position-dependent transverse polarisation and phase is created in a volume from the superposition of RH and LH circularly polarised beams, whose amplitude and phases are carefully structured. Spatial points characterised by the same state of elliptic polarisation lie on the filaments (a). The 3D polarisation texture can be visualised by colouring the filaments according to the position of its polarisation ellipse on the Poincaré sphere (b). The azimuthal angle \(\alpha\), representing the ellipse orientation, is coloured with the hues and the polar angle \(\beta\), representing the ellipticity, is associated with the saturation levels. The sphere’s poles, representing the circular polarised states, are black (LH) and white (RH). Each optical state also has a phase, represented by the position of the arrow along the polarisation ellipse. In the transverse plane in (c), states of light are fully described by colours and arrowed ellipses. Along filaments of constant polarisation, the phase on the ellipses varies smoothly, as shown in the insets for three representative planes.
