apparatus , method and storage medium which can provide at least one first electro - magnetic radiation to a sample and at least one second electromagnetic radiation to a reference , such that the first and / or second electromagnetic radiations have a spectrum which changes over time . in addition , a first polarization component of at least one third radiation associated with the first radiation can be combined with a second polarization component of at least one fourth radiation associated with the second radiation with one another . the first and second polarizations may be specifically controlled to be at least approximately orthogonal to one another .