The world's smallest molecular optical transistor

Since lasers first appeared nearly 50 years ago, scientists and technicians have dreamed of the ability to create a completely optical circuit in which electrons are replaced by photons.

While the information is easily transmitted by light in fiber optic cables, the optical island information manipulation and processing are relatively complex in converting from photons to electrons and vice versa: slow and consume quite a bit of energy. quantity.

In fact, there is a long way to go to photonic circuits in computers or other everyday applications because these circuits require manipulation in nanometer-size space, which leads to a lot of hard. Moreover, beam lockers, which allow energy from one beam to amplify another, often require large photonic crystals.

Figure 1 . Experimental arrangement: a) energy state of a single molecule, b) duration of laser beam action, c) optical system diagram and optical system snapshot (Nature 460 (2009) 76).

Recently, Vahid Sandoghdar and colleagues at the Swiss Federal Institute of Technology, Zurich (ETH Zurich) have created what they call the world's smallest optical transistor from a single molecule of dye (molecular dye). . Components that work by weakening or amplifying a ' source ' laser depend on the power of the beam at the gate gate , which can help create an all-optical or farther circuit than the Optical computer at a closer approach.

Simple operation.

" By manipulating the attenuation and amplification levels through the laser beam power at the gate pole, we have shown the smallest transistor to the present " - Sandoghdar said. The operation principle of the device is quite simple - according to Sandoghdar: When the molecule is placed in a excited state by the laser beam at the gate pole, it will emit a photon and thereby amplify the power of the beam. ultra source.

The key to creating this optical transistor is to focus the beam on a single molecule at low temperatures, creating a very strong molecular bond that allows the molecule to affect the laser light. Although the strong link was created earlier, it was only conducted in optical cavities where interactions could be enhanced. However, even the smallest optical cavities are larger than a micrometer in size, meaning that the components cannot be made smaller than this device.

Figure 2 .Some results of the experiment: a) the transmission spectrum of the transducer beam for the single molecule in the pump off state, b) the result in the accumulated density state (Nature 460 (2009) 76 ).

High density packaging.

In contrast, the ETH Zurich experiments could lead to high density packaging of nanometer-sized optical transistors. The group's theoretical calculations have also shown that it is possible to build complex circuits where many emitters can be linked to micro waveguides that can carry optical information on one chip.

' And although the experiment is conducted with traditional laser beams, it can also work with single-photon non-traditional light beams ' - Sandoghdar explains -' Means quantitative information death can be handled '.

See details of this work in Nature 460 (2009) 76 .