Beamsplitters do exactly what their name implies, splits a beam. There are a couple different types of beamsplitters. A standard beamsplitter will split the beam by a percentage of the intensity, such as 50% transmission and 50% reflection or 30% transmission and 70% reflection. Non-polarizing beamsplitters are specifically controlled not to alster the S and P polarization states of the incoming light. Polarizing beamsplitters will transmit P polarization and reflect S polarization, allowing the user to add polarized light into a system. Dichroic beamsplitters split incoming light by wavelength and are commonly used in fluorescence applications to separate the excitation and emission paths.