A binary optical compound formed from a preparation of proteorhodopsin, is provided. The preparation is prepared by dissolving proteorhodopsin in distilled water, where the pH is adjusted to be above 11 either by using sodium hydroxide or an appropriate buffer. The preparation is then illuminated with either white light sources, lasers, or irradiation provided from light-emitting diodes. The necessary duration is intensity dependent, varying from a few seconds to a few minutes, depending upon the source and actinic wavelength. The resulting compound has a long lifespan and may be efficiently transitioned between states.