Quarterwave plate as a light beam average component

is a key component in high power CO

2

laser processing mechine.At oblique incidence the multilayer reflectors

including internal and external reflections

have different phase shifts for the two planes of polarlzation.Therefore the design of reflators with specific phase shift have been carried out by computer optimization.The purpose of this paper is to design coating with the relative difference of phase shifts of 90° at 10.6μm.The reflectors with the phase difference of 90°will act as a quarterwave plate.Some advantages over bulk quarterwave plates are that they may be used for any wavelength

may have higher precision of phase shift difference and large apertures.The two design methods

experimental techniques

results and errors analysis are presented.