Finding a proper place for photons in the world full of electrons and their spins

Abstract

Summary form only given. It has been half a century since the photons have been portended to supplant electrons in information transmission, storage, and processing. While spectacular successes have been achieved in optical communications and these advances are slowly working their way into the chip-scale optical interconnects, optical memories have not displaced magnetic storage and are now losing ground to the all-electronic flash memories, and, in information processing the competitive all-optical switching schemes have never materialized. The fundamental reason for these facts is crystal clear - unlike electrons, photons are bosons that do not have charge and are not subjected to Pauli principle, and hence they are ideally suited for the unhindered propagation over spectacular distances while requiring quite an effort in order to be switched. We confirm this intuitive understanding by comparing switching powers, speeds and noise of electronic and photonic devices, such as modulators, all optical switches and buffers. At the same time we show that in terms of loss and bandwidth photons are unmatchable for information transmission even over the shortest of distances and cannot be replaced by any known entity, including currently popular plasmons. With electrons and photons having their clearly defined niches the main challenge lays in developing means for seamless connectivity between electronics and photonics.