Nanophotonic chip-space interfaces for multidimensional nonlinear optics

Nature Materials (2026)Cite this article Reconfigurable interfaces between confined optical modes in integrated photonic chips and structured light in free space would benefit fundamental optical science and photonic technologies. Here we exploit the anisotropic nonlinear susceptibility tensors associated with thin-film lithium niobate to construct nanophotonic chip-space interfaces capable of generating and multidimensionally engineering structured light via injections of photons to on-chip waveguides. Harnessing the nonlinear Čerenkov radiation in integrated nonlinear microring resonators, we tailor the spatial profile, polarization state, emission wavelength, topological charge and temporal wave packet of structured optical vortices, exhibiting reconfigurability and tunability. To showcase the capabilities of our platform, we use continuous-wave excitation to generate tunable optical skyrmions via the spin–orbit coupling and multistate integrated vortex microcombs in the short near-infrared range via synergistic χ(2) and χ(3) nonlinear optical processes. 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Opt. 20, 083501 (2018).Article Google Scholar Download referencesThis research is supported by the National Key R&D Program of China (2021YFA1400800, X.W.), the National Natural Science Foundation of China (12293052, C.-H.D.; 12361141824, J.L.; 12274474, D.W.; 62522519, B.C.; 12574428, B.C.; 92250302, C.-H.D.; 12434012, Q.Z.; 62535013, Q.Z.), the Natural Science Foundation of Guangdong (2022B1515020067, D.W.; 2023B1515120070, J.L.; 2024B1515040013, D.W.; 2025B1515020004, B.C.), Guangdong Introducing Innovative and Entrepreneurial Teams of ‘The Pearl River Talent Recruitment Program’ (2021ZT09X044, S.F.) and Innovation Program for Quantum Science and Technology (2023ZD0300804, S.W.). We thank C. Zou for an insightful discussion and J. Li and H. Liang for loaning the equipment. This work was partially carried out at the USTC Center for Micro and Nanoscale Research and Fabrication.These authors contributed equally: Dunzhao Wei, Bo Chen, Shuai Wan, Yixuan Wang.State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics, Sun Yat-sen University, Guangzhou, ChinaDunzhao Wei, Bo Chen, Yixuan Wang, Jiantao Ma, Chun Chang, Guixin Qiu, Xuehua Wang & Jin LiuCAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, ChinaShuai Wan, Pi-Yu Wang & Chun-hua DongCAS Center for Excellence in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, ChinaShuai Wan, Pi-Yu Wang & Chun-hua DongCollege of Science, National University of Defense Technology, Changsha, ChinaZelin Tan, Yan Chen & Tian JiangInstitute of Advanced Photonics Technology, School of Information Engineering, Guangdong University of Technology, Guangzhou, ChinaXiaoshan Huang & Songnian FuSchool of Optical-Electrical and Computer Engineering, University of Shanghai for Science and Technology, Shanghai, ChinaQiwen ZhanZhangjiang Laboratory, Shanghai, ChinaQiwen ZhanMOE Key Laboratory of Weak-Light Nonlinear Photonics, TEDA Applied Physics Institute and School of Physics, Nankai University, Tianjin, ChinaFang BoQuantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area, Shenzhen, ChinaXuehua Wang & Jin LiuSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarJ.L. and D.Z.W. conceived the project. D.Z.W., C.C., X.H.W. and J.L. developed the theory. B.C., D.Z.W., S.W. and Y.X.W. performed the numerical simulations. S.W., P.Y.W., Z.L.T. and Y.C. fabricated the devices. D.Z.W., B.C., S.W., Y.X.W., J.T.M. and J.L. built the setup and characterized the devices. D.Z.W., B.C., S.W., Y.X.W., J.T.M., G.X.Q., X.S.H, T.J., S.N.F., C.H.D. and J.L. analysed the data. D.Z.W. and J.L. wrote the manuscript with inputs from all authors. D.Z.W., S.N.F., Q.W.Z., F.B., X.H.W., C.H.D. and J.L. supervised the project.Correspondence to Dunzhao Wei, Xuehua Wang, Chun-hua Dong or Jin Liu.The authors declare no competing interests.Nature Materials thanks Shai Tsesses 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.(a) Fabrication processes of the TFLN microring. (b, c) Top-view and cross-section SEM images of a typical TFLN microring. (d, e, f) Transmission spectra and quality factors of x-cut microring (Sample 1) for generation of scalar SF vortices in cases 1 and 2, z-cut microring (Sample 2) for generation of vector SF vortices in cases 3 and 4, z-cut microring (Sample 3) for generation of short NIR vortex microcombs. (g) Thermal tuning of three resonant TM modes for the x-cut microring (Sample 1). The microring is placed on the platform with a temperature controller in the fiber-waveguide coupling system. As the temperature increased from 30∘C to 100∘C, the resonant wavelength for the same mode order exhibits a redshift of approximately 0.8 nm. This shift is larger than half of the free spectral range (1.4 nm for Sample 1), allowing for compensation of the SF wavelength difference for SF optical vortices with even and odd TCs, as shown in Fig. 3d. (h) Simulated and measured integrated dispersions of the z-cut microring (Sample 3) for the generation of Kerr solitons.(a) The setup for characterizing single-wavelength SF vortices. (b) Schematic of TC measurement in cases 1 and 2 via on-chip interference. (c) The setup for producing and characterizing the short NIR vortex microcombs. WP: waveplate; EDFA: Erbium Doped Fiber Amplifier; BS: beam splitter; FPC: fiber polarization controllers; Fiber BS: 2 × 2 fiber beam splitter; M: mirror.(a) Dependence of the effective nonlinear coefficients on the azimuthal angle for the four cases. The non-zero nonlinear coefficients of the TFLN are set to χ22=2pm/V, χ31= χ15=5pm/V, and χ33=30 pm/V. (b) Simulated far-field intensity patterns in cases 1 to 4 based on the dominant polarization components given in Table 1. The simulated results match well with the experimental results in Fig. 2b,f,j,n. (c) Simulated far-field intensity patterns for lWGM = m − n = ± 4, ± 2, ± 2 and ± 1 in cases 1 to 4, respectively, being in excellent agreement with experimental results in Fig. 2d,h,l,p. (d) Simulation on intensity patterns in the x-y plane induced by z-component of the NP in case 4 by using the dipole model representing the SH sources in finite-different time-domain (FDTD). The z-polarized dipoles azimuthally distributing around a circle in the cylindrical coordinate (ρ, φ, z) mimic the NPs for generating out-of-plane SH wave that are produced by χ33 but confined within a circularly subwavelength diffraction structure. Here, ρ and φ are the polar radius and azimuthal angle, respectively, while z denotes the distance from the microring plane. A monitor is placed above the ring to collect the diffracted SH field in the plane perpendicular to the z-axis. (e) The simulated SH far-field intensity distribution, horizontal (y-) polarized intensity distribution and vertical (x-) polarized intensity distribution, respectively. The rotation of 90∘ between x-polarization and y-polarization reveals a a cylindrical vector beam \({[\cos \varphi \sin \varphi ]}^{T}\), being excellently agreement with the experiment results in Fig. 2n.(a) Spectra of the fundamental and SH waves for the four cases. The degenerated fundamental wavelengths are 1562.04 nm, 1561.30 nm, 1563.37 nm, and 1563.91 nm, leading to the exactly frequency-doubled emission at 781.02 nm, 780.65 nm, 781.69 nm, and 781.96 nm, respectively. (b) Spectra of the fundamental and SF waves for lWGM = m − n = ± 4, ± 2, ± 2 and ± 1 in cases 1 to 4, respectively. The fundamental wavelengths for the four cases are fixed at λm = 1556.55 nm, 1558.43 nm, 1557.91 nm, and 1561.30 nm for CCW modes and λn = 1562.02 nm, 1561.30 nm, 1563.37 nm, and 1563.88 nm for CW modes to get a positive lWGM, while swap them to obtain a negative lWGM. Correspondingly, strong SF signals are located at 779.64 nm, 779.93 nm, 780.31 nm, and 781.29 nm, respectively, demonstrating that the prominent out-of-plane radiation comes from nonlinear interactions of the two counter-propagating fundamental waves. (c) Power dependence of SHG on the pump power of the CCW resonant mode in case 2. (d) Power dependence of SFG on the pump power of the CCW resonant mode in case 2. (e-f) Power dependences of SHG and SFG using the unit of dBm corresponding to (c) and (d), respectively.(a) Intensity profiles of optical vortices carrying a single TC of m − n = 4 at different SF wavelength. (b) Interference patterns between optical vortices in (a) and those carrying a TC of − 4 at the same wavelength. The uniformly distributed 8 antinodes confirm the unchanged TC of lSF = 4 in (a). (c) Intensity profiles of optical vortices carrying single TCs of m − n = 1 to 7 at same SF wavelength. (d) Interference patterns between optical vortices in (c) and those carrying single TCs of -1 to -7, respectively. The number of antinodes following the 2lSF scaling law demonstrates the stable tuning of a single TC. The residual signal near the center in (b) and (d) originates from incompletely filtered SH signals carrying zero TC during the interference measurement.An additional fundamental CCW beam is set to match higher resonant modes with 5 (I), 11 (II), 17 (III), and 23 (IV) FSRs from the λn = 1554.45 nm highlighted in Fig. 5d, resulting in the enhanced SF signals with lWGM = − 5, − 11, − 17, and − 23 at different SF wavelengths in both spectra and the corresponding far-field patterns. Different colors are overlaid on the spectrum and intensity patterns to highlight the amplified SF signals.Supplementary Notes 1–3.Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.Reprints and permissionsWei, D., Chen, B., Wan, S. et al. Nanophotonic chip-space interfaces for multidimensional nonlinear optics. Nat. Mater. (2026). https://doi.org/10.1038/s41563-026-02570-1Download citationReceived: 04 June 2025Accepted: 06 March 2026Published: 03 April 2026Version of record: 03 April 2026DOI: https://doi.org/10.1038/s41563-026-02570-1Anyone you share the following link with will be able to read this content:Sorry, a shareable link is not currently available for this article. 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