Alternative method for measuring the phase retardation and fast axis of a wave plate
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An alternative method is proposed for simultaneously measuring the phase retardation and fast axis angle of a wave plate by utilizing a radially polarized symmetric light beam. A horizontal polarized laser is passed through a spatial filter, a zero-order vortex half-wave retarder, for measuring the light beam. An analyzer and a charge-coupled device are used for the measurement. The charge-coupled device captures two intensity variation patterns before and after a wave plate to be tested is rotated by 45° in any initial fast axis angle direction. Through analysis of the intensity values, the phase retardation and fast axis angle of the wave plate to be tested can be accurately determined using mean calculation. To validate the proposed method, half-wave and quarter-wave plates were measured experimentally. The measurement errors of phase retardation and fast axis angle were approximately 0.087° and 0.094°, respectively.
KeywordsRadially polarized light Wave plate Phase retardation Fast axis angle
The authors would like to thank the National Science Council of the Republic of China, Taiwan, for financially supporting this research under Contract no. MOST 107–2221–E–035–068–MY2.