Figure 3
From: Realization of Tunable Photonic Spin Hall Effect by Tailoring the Pancharatnam-Berry Phase
(a) Experimental apparatus for generating the CVBs and measuring the tunable photonic SHE. Part 1: A collimated and horizontal polarized TEM00 beam from a He-Ne laser (632.8 nm, 21 mW) followed by a polarizer (P1) is converted into a vortex-bearing LG0,m beam using a reflective phase-only spatial light modulator (SLM) (Holoeye Pluto-Vis, Germany). Using a modified Mach-Zender interferometer comprised of two beam splitters (BS) and one mirror (M), a LG0,−m beam is produced by an odd number of reflections. A half-wave plate (HWP1) with 45° inclined to horizontal direction converts the horizontal polarization to vertical one and a quarter-wave plate (QWP1) gives the two beams orthogonal circular polarizations. Their collinear superposition generates a CVB on the equator of the higher-order Poincaré sphere. In order to determine the concrete point on the equator, two cascaded half-wave plates (HWP2 and HWP3) are employed19,27. Part 2: The CVB passes through the homogeneous birefringent waveplate (HBW). The photonic SHE can be detected by Part 3 (a quarter-wave plate followed by a polarizer and a CCD camera) which is a typical setup for measuring the Stokes parameters S3. The inset: An example of the phase picture displayed on SLM. (b) Higher-order Poincaré spheres. Left panel for the case of m = 1 and the right panel for m = −1. The equator represents the linearly polarized CVBs, the poles circularly polarized vortex beams and intermediate points between the poles and equator elliptically polarized CVBs. The solid circles with arrows in the north/south poles indicate locally circular polarizations, while the dashed ones represent the direction of vortex.
