Abstract
Several recent applications in polarimetry, ellipsometry, spectropolarimetry, and multiplexed galvanometric scanners require a single compact beam splitter capable of splitting an input beam of light into four or more components. Of special interest is to design a single beam splitter to produce multiple components of equal powers. We present a specific IR design of a parallel-slab beam splitter that uses a fused silica as a slab material, and it is strip- coated with Germanium thin film on the front and with a uniform silver coat on the back. Equal powers among the first four components can be achieved when the reflectance levels on the first, second, third, and fourth strip is equal to 20 percent, 68 percent, 54 and 18 percent respectively. Specific designs at wavelengths of 1.55, 2 and 5 micrometers are presented. At a wavelength of 5 micrometers , glass shows some absorption and is replaced by another transparent slab material. The choice of varying the otpical material of the slab and metric thickness of each strip provides a great flexibility in the design and operation of the beam splitter over a wide range of applications.
