Abstract: A modulated infrared source is disclosed in which spatial-on-spatial modulation is accomplished by the rotation of two sets of beam forming optics about an infrared source. Close to 100% of the energy from the infrared source is focused by rotating two sets of parabolically shaped mirrors about the IR source such that energy losses due toe modulation technique are minimized. The speed of the rotation of the reflective optics is minimized while maintaining sufficiently high modulation frequencies the initial provision of four beams from a single source. This is accomplished by the first set of beam forming optics. Moreover, the effects of unwanted reflection are minimized by the four beam configuration. The four beams are then themselves modulated by the second set of beam forming optics.