Another problem is that, in some applications it is desirable to combine different beams of light that may not consistently or at all have different spectra or different polarizations that would permit combination of the different beams using conventional light combiners such as a dichroic mirror (which may be used to combine two beams of light having different wavelengths) or a polarizing beam splitter (which may be used to combine two beams of light having different polarizations). A typical dichroic mirror cannot be used to efficiently combine beams that have the same wavelength or wavelengths that differ from one another by less than at least about 10nm. A typical polarizing beam splitter, which may be used to combine beams, operates most efficiently for orthogonal polarization states.