Guiding of visible photons at the ångström thickness limit


Optical waveguides are vital components of data communication system technologies, but their scaling down to the nanoscale has remained challenging despite advances in nano-optics and nanomaterials. Recently, we theoretically predicted that the ultimate limit of visible photon guiding can be achieved in monolayer-thick transition metal dichalcogenides. Here, we present an experimental demonstration of light guiding in an atomically thick tungsten disulfide membrane patterned as a photonic crystal structure. In this scheme, two-dimensional tungsten disulfide excitonic photoluminescence couples into quasi-guided photonic crystal modes known as resonant-type Wood’s anomalies. These modes propagate via total internal reflection with only a small portion of the light diffracted to the far field. Such light guiding at the ultimate limit provides more possibilities to miniaturize optoelectronic devices and to test fundamental physical concepts.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Atomically thick WS2 PhC membranes.
Fig. 2: Experimental demonstration of WS2 guided-mode resonances.
Fig. 3: The angle dependence of WS2 guided-mode resonances.
Fig. 4: The thickness dependence of WS2 guided-mode resonances.
Fig. 5: Observation of monolayer WS2 guided-mode resonance.
Fig. 6: Coupling of the WS2 waveguide mode to guided-mode resonance.


  1. 1.

    Ye, Z. et al. Probing excitonic dark states in single-layer tungsten disulphide. Nature 513, 214–218 (2014).

    CAS  Article  Google Scholar 

  2. 2.

    Ramasubramaniam, A. Large excitonic effects in monolayers of molybdenum and tungsten dichalcogenides. Phys. Rev. B 86, 115409 (2012).

    Article  Google Scholar 

  3. 3.

    Mak, K. F. & Shan, J. Photonics and optoelectronics of 2D semiconductor transition metal dichalcogenides. Nat. Photon. 10, 216–226 (2016).

    CAS  Article  Google Scholar 

  4. 4.

    Ye, Y. et al. Monolayer excitonic laser. Nat. Photon. 9, 733–737 (2015).

    CAS  Article  Google Scholar 

  5. 5.

    Splendiani, A. et al. Emerging photoluminescence in monolayer MoS2. Nano Lett. 10, 1271–1275 (2010).

    CAS  Article  Google Scholar 

  6. 6.

    Mak, K. F., Lee, C., Hone, J., Shan, J. & Heinz, T. F. Atomically thin MoS2: a new direct-gap semiconductor. Phys. Rev. Lett. 105, 136805 (2010).

    Article  Google Scholar 

  7. 7.

    Tongay, S. et al. Defects activated photoluminescence in two-dimensional semiconductors: interplay between bound, charged, and free excitons. Sci. Rep. 3, 2657 (2013).

    Article  Google Scholar 

  8. 8.

    Malard, M., Alencar, T. V., Barboza, A. P. M., Mak, K. F. & de Paula, A. M. Observation of intense second harmonic generation from MoS2 atomic crystals. Phys. Rev. B 87, 201401(R) (2013).

    Article  Google Scholar 

  9. 9.

    Li, Y. et al. Probing symmetry properties of few-layer MoS2 and h-BN by optical second-harmonic generation. Nano Lett. 13, 3329–3333 (2013).

    CAS  Article  Google Scholar 

  10. 10.

    Yi, F. et al. Optomechanical enhancement of doubly resonant 2D optical nonlinearity. Nano Lett. 16, 1631–1636 (2016).

    CAS  Article  Google Scholar 

  11. 11.

    Zhang, X. et al. Unidirectional doubly enhanced MoS2 emission via photonic Fano resonances. Nano Lett. 17, 6715–6720 (2017).

    CAS  Article  Google Scholar 

  12. 12.

    Zhang, X. et al. Dynamic photochemical and optoelectronic control of photonic Fano resonances via monolayer MoS2 trions. Nano Lett. 18, 957–963 (2018).

    CAS  Article  Google Scholar 

  13. 13.

    Khurgin, J. B. Two-dimensional exciton–polariton—light guiding by transition metal dichalcogenide monolayers. Optica 2, 740 (2015).

    CAS  Article  Google Scholar 

  14. 14.

    Fan, S. & Joannopoulos, J. D. Analysis of guided resonances in photonic crystal slabs. Phys. Rev. B 65, 235112 (2002).

    Article  Google Scholar 

  15. 15.

    García de Abajo, F. J. Colloquium: light scattering by particle and hole arrays. Rev. Mod. Phys. 79, 1267–1290 (2007).

    Article  Google Scholar 

  16. 16.

    Gomez-Medina, R., Laroche, M. & Saenz, J. J. Extraordinary optical reflection from sub-wavelength cylinder arrays. Opt. Express 14, 3730–3737 (2006).

    Article  Google Scholar 

  17. 17.

    Wang, S. S. & Magnusson, R. Theory and applications of guided-mode resonance filters. Appl Opt. 32, 2606–2613 (1993).

    CAS  Article  Google Scholar 

  18. 18.

    Li, Y. et al. Measurement of the optical dielectric function of monolayer transition–metal dichalcogenides: MoS2, MoSe2, WS2, and WSe2. Phys. Rev. B 90, 205422 (2014).

    Article  Google Scholar 

  19. 19.

    Hunsperger R. G. Integrated Optics: Theory and Technology (Springer, 2009).

  20. 20.

    Crozier, K. B. et al. Air-bridged photonic crystal slabs at visible and near-infrared wavelengths. Phys. Rev. B 73, 115126 (2006).

    Article  Google Scholar 

  21. 21.

    Fan, S., Suh, W. & Joannopoulos, J. D. Temporal coupled-mode theory for the Fano resonance in optical resonators. J. Opt. Soc. Am. A 20, 569–572 (2003).

    Article  Google Scholar 

  22. 22.

    Taillaert, D. et al. An out-of-plane grating coupler for efficient butt-coupling between compact planar waveguides and single-mode fibers. IEEE J. Quantum Electron 38, 949–955 (2002).

    CAS  Article  Google Scholar 

  23. 23.

    Yang, J. et al. Wafer-scale synthesis of thickness-controllable MoS2 films via solution-processing using a dimethylformamide/n-butylamine/2-aminoethanol solvent system. Nanoscale 7, 9311–9319 (2015).

    CAS  Article  Google Scholar 

  24. 24.

    Yu, H. et al. Wafer-scale growth and transfer of highly-oriented monolayer MoS2 continuous films. ACS Nano 11, 12001–12007 (2017).

    CAS  Article  Google Scholar 

  25. 25.

    Tao, J. et al. Growth of wafer-scale MoS2 monolayer by magnetron sputtering. Nanoscale 7, 2497–2503 (2015).

    CAS  Article  Google Scholar 

Download references


This work was partially supported by the National Science Foundation (NSF) under the NSF 2-DARE Program (EFMA-1542879 and EFMA-1542863) and DMR-1709996. We thank R. Agarwal and R. Bratschitsch for useful discussions during the early stages of this work.

Author information




X.Z. and E.C. conceived the idea. X.Z. and C.D.-E. fabricated the devices. J.G., A.L.B. and V.M.M. provided the WS2 crystals and their reflection spectra. X.Z. performed theoretical modelling. X.Z. and C.D.-E. performed optical measurements and data analysis. C.D.-E. performed the atomic force microscopy measurements. J.K provided the theoretical support for the original 2D waveguiding analysis. E.C. supervised the study. All the authors contributed to the writing of the paper.

Corresponding author

Correspondence to Ertugrul Cubukcu.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary information

Supplementary Sections 1–18, Supplementary Figs. 1–25, Supplementary Refs. 1–36.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Zhang, X., De-Eknamkul, C., Gu, J. et al. Guiding of visible photons at the ångström thickness limit. Nat. Nanotechnol. 14, 844–850 (2019).

Download citation

Further reading


Find nanotechnology articles, nanomaterial data and patents all in one place. Visit Nano by Nature Research