Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

A single-molecule optical transistor


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 atoms1,2,3,4,5,6,7,8,9. 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 beams7. However, single-emitter manipulation of photonic signals has remained elusive and has only been studied in high-finesse microcavities10,11,12,13 or waveguides8,14. 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.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Diagrams of the experiment.
Figure 2: Attenuation and amplification of a laser beam by a single molecule.
Figure 3: Coherent scattering phase shift of π on population inversion.
Figure 4: The nonlinear response of a population-inverted molecule.

Similar content being viewed by others


  1. Tans, S. J., Verschueren, A. R. M. & Dekker, C. Room-temperature transistor based on a single carbon nanotube. Nature 393, 49–52 (1998)

    Article  ADS  CAS  Google Scholar 

  2. Park, J. et al. Coulomb blockade and the Kondo effect in single-atom transistors. Nature 417, 722–725 (2002)

    Article  ADS  CAS  Google Scholar 

  3. Liang, W., Shores, M. P., Bockrath, M., Long, J. R. & Park, H. Kondo resonance in a single-molecule transistor. Nature 417, 725–729 (2002)

    Article  ADS  CAS  Google Scholar 

  4. Davidovich, L., Maali, A., Brune, M., Raimond, J. M. & Haroche, S. Quantum switches and nonlocal microwave fields. Phys. Rev. Lett. 71, 2360–2363 (1993)

    Article  ADS  CAS  Google Scholar 

  5. Harris, S. E. & Yamamoto, Y. Photon switching by quantum interference. Phys. Rev. Lett. 81, 3611–3614 (1998)

    Article  ADS  CAS  Google Scholar 

  6. Micheli, A., Daley, A. J., Jaksch, D. & Zoller, P. Single atom transistor in a 1d optical lattice. Phys. Rev. Lett. 93, 140408 (2004)

    Article  ADS  CAS  Google Scholar 

  7. Dawes, A. M. C., Illing, L., Clark, S. M. & Gauthier, D. J. All-optical switching in rubidium vapor. Science 308, 672–674 (2005)

    Article  ADS  CAS  Google Scholar 

  8. Chang, D. E., Sorensen, A. S., Demler, E. A. & Lukin, M. D. A single-photon transistor using nanoscale surface plasmons. Nature Phys. 3, 807–812 (2007)

    Article  ADS  CAS  Google Scholar 

  9. Vaishnav, J., Ruseckas, J., Clark, C. W. & Juzelunas, G. Spin field effect transistors with ultracold atoms. Phys. Rev. Lett. 101, 265302 (2008)

    Article  ADS  CAS  Google Scholar 

  10. Imamoglu, A., Schmidt, H., Woods, G. & Deutsch, M. Strongly interacting photons in a nonlinear cavity. Phys. Rev. Lett. 79, 1467–1470 (1997)

    Article  ADS  CAS  Google Scholar 

  11. Duan, L.-M. & Kimble, H. J. Scalable photonic quantum computation through cavity-assisted interactions. Phys. Rev. Lett. 92, 127902 (2004)

    Article  ADS  Google Scholar 

  12. Birnbaum, K. M. et al. Photon blockade in an optical cavity with one trapped atom. Nature 436, 87–90 (2005)

    Article  ADS  CAS  Google Scholar 

  13. Schuster, I. et al. Nonlinear spectroscopy of photons bound to one atom. Nature Phys. 4, 382–385 (2008)

    Article  ADS  CAS  Google Scholar 

  14. Shen, J.-T. & Fan, S. Strongly correlated two-photon transport in a one-dimensional waveguide coupled to a two-level system. Phys. Rev. Lett. 98, 153003 (2007)

    Article  ADS  Google Scholar 

  15. Loudon, R. Quantum Theory of Light (Oxford Univ. Press, 2000)

    MATH  Google Scholar 

  16. Zumofen, G., Mojarad, N. M., Sandoghdar, V. & Agio, M. Perfect reflection of light by an oscillating dipole. Phys. Rev. Lett. 101, 180404 (2008)

    Article  ADS  CAS  Google Scholar 

  17. Moerner, W. E. & Orrit, M. Illuminating single molecules in condensed matter. Science 283, 1670–1676 (1999)

    Article  ADS  CAS  Google Scholar 

  18. Moerner, W. E. & Kador, L. Optical detection and spectroscopy of single molecules in a solid. Phys. Rev. Lett. 62, 2535–2538 (1989)

    Article  ADS  CAS  Google Scholar 

  19. Orrit, M. & Bernard, J. Single pentacene molecules detected by fluorescence excitation in a p-terphenyl crystal. Phys. Rev. Lett. 65, 2716–2719 (1990)

    Article  ADS  CAS  Google Scholar 

  20. Plakhotnik, T. & Palm, V. Interferometric signatures of single molecules. Phys. Rev. Lett. 87, 183602 (2001)

    Article  ADS  Google Scholar 

  21. Gerhardt, I. et al. Strong extinction of a laser beam by a single molecule. Phys. Rev. Lett. 98, 033601 (2007)

    Article  ADS  CAS  Google Scholar 

  22. Wrigge, G., Gerhardt, I., Hwang, J., Zumofen, G. & Sandoghdar, V. Efficient coupling of photons to a single molecule and the observation of its resonance fluorescence. Nature Phys. 4, 60–66 (2008)

    Article  ADS  CAS  Google Scholar 

  23. Lettow, R. et al. Realization of two Fourier-limited solid-state single-photon sources. Opt. Express 15, 15842–15847 (2007)

    Article  ADS  CAS  Google Scholar 

  24. Lounis, B., Jelzko, F. & Orrit, M. Single molecules driven by strong resonant fields: hyper-Raman and subharmonic resonances. Phys. Rev. Lett. 78, 3673–3676 (1997)

    Article  ADS  Google Scholar 

  25. Klar, T., Jakobs, S., Dyba, M., Egner, A. & Hell, S. W. Fluorescence microscopy with diffraction resolution barrier broken by stimulated emission. Proc. Natl Acad. Sci. USA 97, 8206–8210 (2000)

    Article  ADS  CAS  Google Scholar 

  26. Kühn, S., Håkanson, U., Rogobete, L. & Sandoghdar, V. Enhancement of single molecule fluorescence using a gold nanoparticle as an optical nano-antenna. Phys. Rev. Lett. 97, 017402 (2006)

    Article  ADS  Google Scholar 

  27. Rogobete, L., Kaminski, F., Agio, M. & Sandoghdar, V. Design of nanoantennae for the enhancement of spontaneous emission. Opt. Lett. 32, 1623–1625 (2007)

    Article  ADS  Google Scholar 

  28. Chizhik, A. et al. Tuning the fluorescence emission spectra of a single molecule with a variable optical subwavelength metal microcavity. Phys. Rev. Lett. 102, 073002 (2009)

    Article  ADS  Google Scholar 

  29. Stobin'ska, M., Alber, G. & Leuchs, G. Perfect excitation of a matter qubit by a single photon in free space. Europhys. Lett. 86, 14007 (2009)

    Article  ADS  Google Scholar 

  30. Gerhardt, I. et al. Coherent state preparation and observation of Rabi oscillations in a single molecule. Phys. Rev. A 79, 011402(R) (2009)

    Article  ADS  Google Scholar 

Download references


This work was supported by the Swiss National Foundation (SNF) and ETH Zurich (QSIT, grant no. PP-01 07-02). We thank I. Gerhardt and G. Wrigge for their contributions to this project. V.S. thanks X. S. Xie for his hospitality at Harvard University during the writing process of this manuscript.

Author information

Authors and Affiliations


Corresponding author

Correspondence to V. Sandoghdar.

PowerPoint slides

Rights and permissions

Reprints and permissions

About this article

Cite this article

Hwang, J., Pototschnig, M., Lettow, R. et al. A single-molecule optical transistor. Nature 460, 76–80 (2009).

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing