Polarization measuring system PEM 100 series

opticalfor industrial applications

Dual PEM systems provide the capability to make real time polarization analysis measurements. When only one PEM is used, two measurements must be made with the sample rotated 45° after the first measurement. However, measurements can be made in real time using two PEMs mounted at 45° with respect to each other. Hinds Instruments has four standard dual PEM choices for applications that require different useful apertures and measurements in different spectral regions. The I/FS50-60 (and I/FS50-55, I/FS47-50) system uses the series I PEM. The Series l PEM has a rectangular shaped optic that, in essence, limits the useful aperture of the PEM. These small systems are practical when the light source has a small beam diameter. Therefore, if the application for the dual PEM involves a light source consisting of only one laser, this is a viable option. The II/FS20-23 and the II/FS42-47 systems also employ high quality fused silica as the optical material and have a transmission range of 170nm to 2.6µm. Both models are completely functional in the visible and near IR light spectral regions. However, the II/FS20-23 system has the benefit of a larger aperture. This is especially useful if the light source has a large beam diameter or more than one light source is to be accommodated. This dual PEM is typically used in a Stokes polarimeter system to measure the orientation of the linear component of light emitted from a beam of deuterium atoms injected into tokamak plasma. The II/42-47 is also used in Stokes polarimetry measurements and provides a more compact optical head configuration.