A single-molecule optical transistor

Abstract

The transistor is one of the most influential inventions of modern times and is ubiquitous in present-day technologies. In the continuing development of increasingly powerful computers as well as alternative technologies based on the prospects of quantum information processing, switching and amplification functionalities are being sought in ultrasmall objects, such as nanotubes, molecules or atoms. Among the possible choices of signal carriers, photons are particularly attractive because of their robustness against decoherence, but their control at the nanometre scale poses a significant challenge as conventional nonlinear materials become ineffective. To remedy this shortcoming, resonances in optical emitters can be exploited, and atomic ensembles have been successfully used to mediate weak light beams. However, single-emitter manipulation of photonic signals has remained elusive and has only been studied in high-finesse microcavities or waveguides. Here we demonstrate that a single dye molecule can operate as an optical transistor and coherently attenuate or amplify a tightly focused laser beam, depending on the power of a second 'gating' beam that controls the degree of population inversion. Such a quantum optical transistor has also the potential for manipulating non-classical light fields down to the single-photon level. We discuss some of the hurdles along the road towards practical implementations, and their possible solutions.

Ultimate On-Chip Quantum Amplifier

“…Gy, 42.50.Nn, 85.25.Cp, 74.78.Na The quantum amplifiers are actively used devices and most of them rely on natural intra-atomic or molecular transitions with almost untunable transition frequencies [1,2]. Demonstration of amplification on a single atom or molecule in open space is possible [3], however, extremely difficult due to another common characteristic of natural atoms (molecules, quantum dots): They are relatively weakly coupled to the spatial electromagnetic waves in real experiments [3][4][5][6][7][8], in spite of theoretical feasibility of perfect coupling by careful matching of the spacial modes to the atom [9]. An alternative approach is coupling of the atoms to a field of a high quality resonator [10][11][12][13][14][15], which has been successfully used to demonstrate lasing action on single natural [16,17] and artificial [18,19] atoms.…”

Electromagnetically Induced Transparency on a Single Artificial Atom

“…Scaling the media down to a single atom perfectly coupled to the incident waves leads to qualitatively new properties of EIT: the waves are scattered rather than absorbed. However, the strong interaction between the spatial electromagnetic modes and natural atoms (molecules, quantum dots) is very difficult to realize in practice [4][5][6][7][8][9]. Recently, the strong "atom"-field interaction has been achieved by confining the waves in the 1D transmission line efficiently coupled to an artificial three-level atom [10] -a superconducting quantum circuit.…”

A photonic transistor device based on photons and phonons in a cavity electromechanical system

“…In the past decade, such a device has received a lot of interest in view of its important applications ranging from optical communication and optical quantum computer [2] to quantum information processing [3]. Schemes based on nanoscale surface plasmons [4], microtoroidal resonators [5], a single-molecule [6] and some others [7,8,9] have been proposed to realize photonic transistors. However, practical realization remains challenging because it necessitates large nonlinearities and low losses.…”