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.

Scalable single-mode surface emitting laser via open-Dirac singularities

We are providing an unedited version of this manuscript to give early access to its findings. Before final publication, the manuscript will undergo further editing. Please note there may be errors present which affect the content, and all legal disclaimers apply.


Single-aperture cavities are a key component of lasers, instrumental for the amplification and emission of a single light mode. However, the appearance of high-order transverse modes as cavities size increases has frustrated efforts to scale up cavities whilst preserving single-mode operation since the invention of the laser six decades ago1-8. A suitable physical mechanism that allows single-mode lasing irrespective of the cavity size – a “scale-invariant” cavity or laser – has not been identified yet. Here, we propose and demonstrate experimentally that open-Dirac electromagnetic cavities with linear dispersion – which in our devices are realized by a truncated photonic crystal arranged in a hexagonal pattern – exhibit unconventional scaling of losses in reciprocal space, leading to single-mode lasing that is maintained as the cavity is scaled up in size. The physical origin of this phenomenon lies in the convergence of the complex part of the free spectral range in open-Dirac cavities towards a constant governed by the loss rate of distinct Bloch band, while for common cavities it converges to zero as the size grows, leading to inevitable multi-mode emission. An unconventional flat envelope fundamental mode locks all unit-cells in the cavity in phase, leading to single-mode lasing. We name such sources Berkeley Surface Emitting Lasers (BerkSELs) and demonstrate that their far-field corresponds to a topological singularity of charge two, in agreement with our theory. Open-Dirac cavities unlock new avenues for light-matter interaction and cavity quantum electrodynamics.

Your institute does not have access to this article

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Boubacar Kanté.

Supplementary information

Supplementary Information

This file contains Supplementary Sections A–J, including Supplementary Table 1, Supplementary Figs. 1–18 and Supplementary References.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Contractor, R., Noh, W., Redjem, W. et al. Scalable single-mode surface emitting laser via open-Dirac singularities. Nature (2022).

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI:


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