What happens when a beam splitter is combined with another beam splitter
While you can stack beams side-by-side (spatial combining), this increases the beam's size and "Etendue," essentially making the beam harder to focus. To maintain a sharp, diffraction-limited spot quality ($M^2$), you must use multiplexing methods like dichroic or polarization. A beam splitter or beamsplitter is an optical device that splits a beam of light into a transmitted and a reflected beam. It is a crucial part of many optical experimental and measurement systems, such as interferometers, also finding widespread application in fibre optic telecommunications. Polarization refers to the orientation of the wiggling motion of the light waves.
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