a method and apparatus for modulating light , wherein a light source provides light of a certain wavelength to be modulated by a layer of superconducting material which forms part of a specifically configured plate assembly . the superconducting layer is placed in the optical path of the light source . further the superconducting layer is switched between a partially transparent non - superconducting state and a substantially non - transparent superconducting state by a modulation circuit . the resulting optical pulses transmitted through the superconducting layer are converted from the original wavelength to a lower wavelength by a frequency converting device .