The experimental breakthrough was reported in the latest issue of the journal Science, where researchers from MIT's Research Laboratory of Electronics, together with colleagues from Vienna University of Technology and Harvard University, detailed an all-optical switch that functions analogous to an electronic transistor, the fundamental building block of any computational circuit.
The optical switch uses light rather than electricity (in the case of transistors) to switch between the on and off states, a process described as follows: at the heart of the switch there is a pair of highly reflective mirrors which constitute an optical resonator, and while light as particles (photons) can be stopped by the first mirror, light as a wave (the magnetic field) laps into the space between the mirrors; when the distance between the mirrors is perfectly calibrated to match the wavelength of the light, the mirrors become transparent to the light, allowing it to pass through.
Swapping the electrons for photons inside computational circuits would negate two of the major problems raised by current technology and design, those being high power consumption and heat buildup, the latter alone raising serious doubts regarding the future shrinkage potential of transistors, a transition which is already seeing delays in the planned migration to inferior manufacturing processes.
However, this experimental discovery should be viewed as proof-of-principle work, it is in no way ready or well suited for mainstream adoption. It might very well be however, a landmark moment in the quest for future tech, as in quantum computers.