Beamsplitter
Divides incident light into transmitted and reflected paths with an adjustable splitting ratio, for building beam pickoffs, interferometers, and parallel optical branches.
Open in the canvas →In the real world
A beamsplitter divides an incident beam into a transmitted and a reflected branch, typically using a thin dielectric or metallic coating on a glass cube or plate. Real coatings are rarely perfectly neutral: the reflect/transmit ratio usually depends on both wavelength and polarization, since s- and p-polarized light reflect differently off any dielectric interface away from normal incidence.
In OpticalSetup
The beamsplitter is modeled as an ideal, polarization-independent divider: a single configurable ratio sets what fraction of each incident ray's intensity continues straight through versus reflects at the drawn diagonal, with no wavelength or angle dependence.
A real 50/50 cube is rarely exactly 50/50 across the visible spectrum, and its ratio shifts with polarization — none of that is modeled here. For a splitter whose two outputs are cleanly separated by polarization state rather than a fixed ratio, see the Polarizing BS instead.