Methods and apparatus for combining or separating spectral components by means of a polychromat. A polychromat is employed to combine a plurality of beams, each derived from a separate source, into a single output beam, thereby providing for definition of one or more of the intensity, color, color uniformity, divergence angle, degree of collimation, polarization, focus, or beam waist of the output beam. The combination of sources and polychromat may serve as an enhanced-privacy display and to multiplex signals of multiple spectral components. In other embodiments of the invention, a polychromat serves to disperse spectral components for spectroscopic or de-multiplexing applications.