Optical transistor: Difference between revisions

Revision as of 21:55, 12 April 2014

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Several schemes have been proposed to implement all-optical transistors. In many cases, a proof of concept has been experimentally demonstrated. Among the designs are those based on:

* [[electromagnetically induced transparency]], where the transmission of an [[optical cavity]] or a microresonator is controlled by a weaker flux of gate photons.<ref>{{cite doi|10.1126/science.1238169}</ref><ref>{{cite doi|10.1364/JOSAB.30.001329}}</ref>

* a system of indirect [[exciton]]s (composed of bound pairs of [[electrons]] and [[electron hole|holes]] in double [[quantum well]]s with a static [[dipole moment]]). Indirect excitons, which are created by light and decay to emit light, strongly interact due to their dipole alignment.<ref>{{cite doi|10.1063/1.4866855}}</ref><ref>{{cite doi|10.1364/OL.35.001587}}</ref>

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* a system of microcavity polaritons ([[exciton-polaritons]] inside an [[optical microcavity]]) where, similar to exciton-based optical transistors, [[polariton]]s facilitate effective interactions between photons<ref>{{cite doi|10.1038/ncomms2734b}}</ref>

* [[photonic crystal]] cavities with an active Raman gain medium.<ref>{{cite doi|10.1103/PhysRevA.88.033847}}</ref>

* silicon microrings placed in the path of an optical signal. - gateGate photons heat the silicon microring causing a shift in the optical resonant frequency, leading to a change in transparency at a given frequency of the optical supply.<ref>{{cite doi|10.1364/FIO.2012.FW6C.6}}</ref>

* a dual-mirror optical cavity that holds around 20,000 [[cesium]] atoms trapped by means of optical tweezers and laser-cooled to a few microkelvin. The cesium ensemble did not interact with light and was thus transparent. The length of a round trip between the cavity mirrors equaled an integer multiple of the wavelength of the incident light source, allowing the cavity to transmit the source light. Photons from the gate light field entered the cavity from the side, where each photon interacted with an additional "control" light field, changing a single atom's state to be resonant with the cavity optical field, which changing the field's resonance wavelength and blocking transmission of the source field, thereby "switching" the "device". While the changed atom remains unidentified, [[quantum interference]] allows the the gate photon to be retrieved from the cesium. A single gate photon could redirect a source field containing up to two photons before the retrieval of the gate photon was impeded, above the critical threshold for a positive gain.<ref>{{cite doi|10.1126/science.1242905}}</ref>

== See also ==