Physics · Ch 6 — Optics
Pile of Plates
Pile of Plates
The pile-of-plates arrangement exploits polarisation by reflection to build up a strongly polarised beam. It consists of several parallel glass plates, mounted one behind the other in a tube, tilted at to the axis of the tube (equivalently , the polarising angle for glass, measured from each plate's own normal). A beam of unpolarised light travelling along the tube's axis strikes every plate at exactly this polarising angle; at each surface, the vibration component perpendicular to the plane of incidence is preferentially reflected away while the component parallel to it is preferentially transmitted through, so with a large enough number of plates the transmitted beam becomes almost completely plane polarised. Because the reflected light collected from all the p …
What this figure shows. A stack of parallel glass plates is mounted inside a tube, each plate tilted at 33.7 degrees to the tube's own axis (equivalently, 56.3 degrees to the plate's own normal, the polarising angle for glass). A beam of unpolarised light travelling along the axis strikes every plate at exactly this polarising angle; at each surface the vibration component perpendicular to the plane of incidence is preferentially reflected away while the parallel component is preferentially transmitted, so that after passing through enough plates in t …