A monochromator system applicable in spectrophotometer, polarimeter and ellipsometer systems which operate over a large range of wavelengths, including a stage which enables position adjustment of the location of a source of electromagnetic radiation in lateral (X), longitudinal (Y) and vertical (Z) directions, from a common location outside an enclosure, and including multiple detector systems mounted in a manner which allows easily, sequentially, via mechanical motion, placing a first and then a second thereof so as to receive a beam of electromagnetic radiation.