Chiral nanophotonic interfaces enable propagation direction-dependent interactions between guided optical modes and circularly dichroic materials. Electrical tuning of interface chirality would aid active, switchable non-reciprocity in on-chip optoelectronic and photonic circuitry, but remains an outstanding challenge. Here, we report electrically controllable chirality in a nanophotonic interface with atomically thin monolayer tungsten diselenide (WSe2). Titanium dioxide waveguides are directly fabricated on the surface of low-disorder, boron nitride-encapsulated WSe2. Following integration, photoluminescence from excitonic states into the waveguide can be electrically switched between balanced and directionally biased emission. The operational principle leverages the doping-dependent valley polarization of excitonic states in WSe2. Furthermore, the nanophotonic waveguide can function as a near-field source for diffusive exciton fluxes, which display valley and spin polarizations that are inherited from the interface chirality. Our versatile fabrication approach enables the deterministic integration of photonics with van der Waals heterostructures and could provide optical control over their excitonic and charge-carrier behaviour.
This is a preview of subscription content
Subscribe to Nature+
Get immediate online access to the entire Nature family of 50+ journals
Subscribe to Journal
Get full journal access for 1 year
only $8.25 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Get time limited or full article access on ReadCube.
All prices are NET prices.
The data that support the findings of this study are available from the corresponding author upon reasonable request.
The code used in this study is available from the corresponding author upon reasonable request.
Aiello, A., Banzer, P., Neugebaueru, M. & Leuchs, G. From transverse angular momentum to photonic wheels. Nat. Photonics 9, 789–795 (2015).
Bliokh, K. Y., Rodriguez-Fortuno, F. J., Nori, F. & Zayats, A. V. Spin–orbit interactions of light. Nat. Photonics 9, 796–808 (2015).
Petersen, J., Volz, J. & Rauschenbeutel, A. Chiral nanophotonic waveguide interface based on spin–orbit interaction of light. Science 346, 67–71 (2014).
Mitsch, R., Sayrin, C., Albrecht, B., Schneeweiss, P. & Rauschenbeutel, A. Quantum state-controlled directional spontaneous emission of photons into a nanophotonic waveguide. Nat. Commun. 5, 5713 (2014).
Sayrin, C. et al. Nanophotonic optical isolator controlled by the internal state of cold atoms. Phys. Rev. X 5, 041036 (2015).
Shomroni, I. et al. All-optical routing of single photons by a one-atom switch controlled by a single photon. Science 345, 903–906 (2014).
Scheucher, M., Hilico, A., Will, E., Volz, J. & Rauschenbeutel, A. Quantum optical circulator controlled by a single chirally coupled atom. Science 354, 1577–1580 (2016).
le Feber, B., Rotenberg, N. & Kuipers, L. Nanophotonic control of circular dipole emission. Nat. Commun. 6, 6695 (2015).
Soellner, I. et al. Deterministic photon–emitter coupling in chiral photonic circuits. Nat. Nanotechnol. 10, 775–778 (2015).
Gong, S. H., Alpeggiani, F., Sciacca, B., Garnett, E. C. & Kuipers, L. Nanoscale chiral valley–photon interface through optical spin–orbit coupling. Science 359, 443–447 (2018).
Kapitanova, P. V. et al. Photonic spin Hall effect in hyperbolic metamaterials for polarization-controlled routing of subwavelength modes. Nat. Commun. 5, 3226 (2014).
High, A. A. et al. Visible-frequency hyperbolic metasurface. Nature 522, 192–196 (2015).
Lin, J. et al. Polarization-controlled tunable directional coupling of surface plasmon polaritons. Science 340, 331–334 (2013).
Tang, L. et al. On-chip chiral single-photon interface: isolation and unidirectional emission. Phys. Rev. A 99, 43833 (2019).
Lodahl, P. et al. Chiral quantum optics. Nature 541, 473–480 (2017).
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).
Splendiani, A. et al. Emerging photoluminescence in monolayer MoS2. Nano Lett. 10, 1271–1275 (2010).
Xiao, D., Liu, G. B., Feng, W. X., Xu, X. D. & Yao, W. Coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides. Phys. Rev. Lett. 108, 196802 (2012).
Zeng, H., Dai, J., Yao, W., Xiao, D. & Cui, X. Valley polarization in MoS2 monolayers by optical pumping. Nat. Nanotechnol. 7, 490–493 (2012).
Mak, K. F., He, K., Shan, J. & Heinz, T. F. Control of valley polarization in monolayer MoS2 by optical helicity. Nat. Nanotechnol. 7, 494–498 (2012).
Cao, T. et al. Valley-selective circular dichroism of monolayer molybdenum disulphide. Nat. Commun. 3, 887 (2012).
Chervy, T. et al. Room temperature chiral coupling of valley excitons with spin-momentum locked surface plasmons. ACS Photonics 5, 1281–1287 (2018).
Sun, L. Y. et al. Separation of valley excitons in a MoS2 monolayer using a subwavelength asymmetric groove array. Nat. Photonics 13, 180–184 (2019).
Yang, Z. L., Aghaeimeibodi, S. & Waks, E. Chiral light–matter interactions using spin-valley states in transition metal dichalcogenides. Opt. Express 27, 21367–21379 (2019).
Guo, Q. B. et al. Routing a chiral Raman signal based on spin–orbit interaction of light. Phys. Rev. Lett. 123, 183903 (2019).
Gong, S. H., Komen, I., Alpeggiani, F. & Kuipers, L. Nanoscale optical addressing of valley pseudospins through transverse optical spin. Nano Lett. 20, 4410–4415 (2020).
Liu, W. J. et al. Generation of helical topological exciton–polaritons. Science 370, 600–604 (2020).
Barbone, M. et al. Charge-tuneable biexciton complexes in monolayer WSe2. Nat. Commun. 9, 3721 (2018).
Dey, P. et al. Gate-controlled spin-valley locking of resident carriers in WSe2 monolayers. Phys. Rev. Lett. 119, 137401 (2017).
Rice, W. D. et al. Persistent optically induced magnetism in oxygen-deficient strontium titanate. Nat. Mater. 13, 481–487 (2014).
Lalieu, M. L. M., Lavrijsen, R. & Koopmans, B. Integrating all-optical switching with spintronics. Nat. Commun. 10, 110 (2019).
Cadiz, F. et al. Excitonic linewidth approaching the homogeneous limit in MoS2-based van der Waals heterostructures. Phys. Rev. X 7, 21026 (2017).
Ajayi, O. A. et al. Approaching the intrinsic photoluminescence linewidth in transition metal dichalcogenide monolayers. 2d Mater. 4, 31011 (2017).
Zhou, Y. et al. Probing dark excitons in atomically thin semiconductors via near-field coupling to surface plasmon polaritons. Nat. Nanotechnol. 12, 856–860 (2017).
Butcher, A. et al. High-Q nanophotonic resonators on diamond membranes using templated atomic layer deposition of TiO2. Nano Lett. 20, 4603–4609 (2020).
Ye, Z. L. et al. Efficient generation of neutral and charged biexcitons in encapsulated WSe2 monolayers. Nat. Commun. 9, 3718 (2018).
Li, Z. P. et al. Revealing the biexciton and trion-exciton complexes in BN encapsulated WSe2. Nat. Commun. 9, 3719 (2018).
Yu, T. & Wu, M. W. Valley depolarization due to intervalley and intravalley electron–hole exchange interactions in monolayer MoS2. Phys. Rev. B 89, 205303 (2014).
Singh, A. et al. Long-lived valley polarization of intravalley trions in monolayer WSe2. Phys. Rev. Lett. 117, 257402 (2016).
Scuri, G. et al. Electrically tunable valley dynamics in twisted WSe2/WSe2 bilayers. Phys. Rev. Lett. 124, 217403 (2020).
Kulig, M. et al. Exciton diffusion and halo effects in monolayer semiconductors. Phys. Rev. Lett. 120, 207401 (2018).
Glazov, M. M. Quantum interference effect on exciton transport in monolayer semiconductors. Phys. Rev. Lett. 124, 166802 (2020).
Unuchek, D. et al. Room-temperature electrical control of exciton flux in a van der Waals heterostructure. Nature 560, 340–344 (2018).
Zipfel, J. et al. Exciton diffusion in monolayer semiconductors with suppressed disorder. Phys. Rev. B 101, 115430 (2020).
Rivera, P. et al. Valley-polarized exciton dynamics in a 2D semiconductor heterostructure. Science 351, 688–691 (2016).
Jin, C. H. et al. Imaging of pure spin-valley diffusion current in WS2–WSe2 heterostructures. Science 360, 893–896 (2018).
Unuchek, D. et al. Valley-polarized exciton currents in a van der Waals heterostructure. Nat. Nanotechnol. 14, 1104–1109 (2019).
Costache, M. V., Sladkov, M., Watts, S. M., van der Wal, C. H. & van Wees, B. J. Electrical detection of spin pumping due to the precessing magnetization of a single ferromagnet. Phys. Rev. Lett. 97, 216603 (2006).
Sanchez, O. L., Ovchinnikov, D., Misra, S., Allain, A. & Kis, A. Valley polarization by spin injection in a light-emitting van der Waals heterojunction. Nano Lett. 16, 5792–5797 (2016).
Zutic, I., Fabian, J. & Das Sarma, S. Spintronics: fundamentals and applications. Revi. Mod. Phys. 76, 323–410 (2004).
Cadiz, F. et al. Exciton diffusion in WSe2 monolayers embedded in a van der Waals heterostructure. Appl. Phys. Lett. 112, 152106 (2018).
Liu, E. et al. Gate tunable dark trions in monolayer WSe2. Phys. Rev. Lett. 123, 027401 (2019).
Datta, I. et al. Low-loss composite photonic platform based on 2D semiconductor monolayers. Nat. Photonics 14, 256–262 (2020).
Seol, M. et al. High-throughput growth of wafer-scale monolayer transition metal dichalcogenide via vertical Ostwald ripening. Adv. Mater. 32, 2003542 (2020).
Liu, F. et al. Disassembling 2D van der Waals crystals into macroscopic monolayers and reassembling into artificial lattices. Science 367, 903–906 (2020).
Huang, Y. et al. Universal mechanical exfoliation of large-area 2D crystals. Nat. Commun. 11, 2453 (2020).
Mannix, A. J. et al. Robotic four-dimensional pixel assembly of van der Waals Solids. Nat. Nanotechnol. https://doi.org/10.1038/s41565-021-01061-5 (2022).
Seyler, K. L. et al. Signatures of moire-trapped valley excitons in MoSe2/WSe2 heterobilayers. Nature 567, 66–70 (2019).
Tran, K. et al. Evidence for moire excitons in van der Waals heterostructures. Nature 567, 71–75 (2019).
Jin, C. H. et al. Observation of moire excitons in WSe2/WS2 heterostructure superlattices. Nature 567, 76–80 (2019).
Ciarrocchi, A. et al. Polarization switching and electrical control of interlayer excitons in two-dimensional van der Waals heterostructures. Nat. Photonics 13, 131–136 (2019).
High, A. A., Novitskaya, E. E., Butov, L. V., Hanson, M. & Gossard, A. C. Control of exciton fluxes in an excitonic integrated circuit. Science 321, 229–231 (2008).
Jauregui, L. A. et al. Electrical control of interlayer exciton dynamics in atomically thin heterostructures. Science 366, 870–875 (2019).
Liu, Y. et al. Electrically controllable router of interlayer excitons. Sci. Adv. https://doi.org/10.1126/sciadv.aba1830 (2020).
Li, J. et al. Valley relaxation of resident electrons and holes in a monolayer semiconductor: dependence on carrier density and the role of substrate-induced disorder. Phys. Rev. Mater. 5, 044001 (2021).
Robert, C. et al. Spin/valley pumping of resident electrons in WSe2 and WS2 monolayers. Nat. Commun. 12, 5455 (2021).
Hao, K., Shreiner, R., & High, A. A. Optically controllable magnetism in atomically thin semiconductors. Preprint at https://arxiv.org/abs/2108.05931 (2021).
Guddala, S. et al. All-optical nonreciprocity due to valley polarization pumping in transition metal dichalcogenides. Nat. Commun. 12, 3746 (2021).
Zomer, P. J., Guimarães, M. H. D., Brant, J. C., Tombros, N. & van Wees, B. J. Fast pick up technique for high quality heterostructures of bilayer graphene and hexagonal boron nitride. Appl. Phys. Lett. 105, 13101 (2014).
This work made use of the Pritzker Nanofabrication Facility part of the Pritzker School of Molecular Engineering at the University of Chicago, which receives support from Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-2025633), a node of the National Science Foundation’s National Nanotechnology Coordinated Infrastructure. This work also made use of the shared facilities at the University of Chicago Materials Research Science and Engineering Center, supported by the National Science Foundation under award number DMR-2011854. Funding was provided by Army Research Office Grant #W911NF-20-1-0217 (R.S. and K.H.) and the Boeing company (A.B.). A.B. acknowledges support from the NSF Graduate Research Fellowship under grant no. DGE-1746045. We acknowledge Y. Zhou, J. Park and A. Dibos for helpful discussions.
The authors declare no competing interests.
Peer review information
Nature Photonics thanks Mikhail Kats and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Shreiner, R., Hao, K., Butcher, A. et al. Electrically controllable chirality in a nanophotonic interface with a two-dimensional semiconductor. Nat. Photon. 16, 330–336 (2022). https://doi.org/10.1038/s41566-022-00971-7
Nature Photonics (2022)