The same equations can be worked backwards with the goal of scanning a 4 cm^-1 spectrum (i.e., interferogram) in one millisecond. The result derived in this slide can be reduced by a factor of 4 if bi-directional data acquisition is used. For a 30 gram mirror the force required is about 380 Newtons (85 lbs for the SI-challenged). It might be possible to reach these levels of force with the use of a rare earth magnet and a powerful high voltage power supply. Even if a mirror assembly could withstand forces of this magnitude, the reaction force would almost certainly disturb other optical components.