Electromagnetic wave polarisation changer - is by rotating the plane of polarisation of the waves

摘要

Two or more metallic reflecting surfaces, fixed or movable are arranged so that the emergent ray is parallel or antiparallel to the incident ray. Plane polarised light is in general converted to elliptically polarised on reflection, but if the wavelength lies between the millimetre range and the visible range, the ellipse is narrow. A second reflection at suitable angle of incidence is used to cancel out the phase changes produced at the first reflection, and the final result is a change in the position of the plane of polarisation. The actual angles of incidence are to be calculated from the optical properties of the metal at the wavelength used. It is also possible to use this principle to change the position of the axis of the ellipse in the case of elliptically polarised light.