Beamsplitters are used to reflect a certain percentage of incident energy, while transmitting the remaining energy. In most cases, beamsplitters are angle, wavelength, and polarization sensitive. Most beamsplitter coatings are highly polarization sensitive. Thus, if the source’s polarization state varies with time, as in some randomly polarized lasers, the beamsplitters transmission will also vary with time. The beamsplitters described here are designed for use at 45° angle of incidence and 10.6µm wavelength. At this angle of incidence, there can be significant differences in the transmittance/reflectance values for s and p-polarizations.
