Light in the visible spectrum is modulated using an array of modulation elements, and control circuitry connected to the array for controlling each of the modulation elements independently, each of the modulation elements having a surface which is caused to exhibit a predetermined impedance characteristic to particular frequencies of light. The motor is mounted on a suspension frame. Preferably to have the greatest impact on chamber cleaning efficiency, the mirror polished surface is a surface of a component such as a gas distribution plate or a backing plate, andor is a surface of a plurality of smaller components so as to constitute a large percentage of the surface area exposed to the reactive species.