Transformation of polarization form to allow accurate intensity measurements with polarization sensitive instruments.

A passive optical device is described which produces a plane polarized transmitted beam, proportional in intensity to the incident beam and independent of the polarization of the incident beam. The transmitted beam is always attenuated by a factor of (1/2), and the device works equally well with monochromatic or white light. A mathematical model using Jones matrices is given, and experimental data are presented to support the model. Use of the device in the absolute calibration of polarization sensitive monochromators and in the determination of absolute atomic cross sections is also discussed.