near-zero-index photonics

exploring wave propagation and light-matter interactions in media with vanishing refractive indices

introduction

The field of near-zero-index (NZI) photonics investigates materials where the effective permittivity, permeability, or both approach zero simultaneously. In these exotic media, the phase velocity of light approaches infinity, leading to a decoupling of spatial and temporal field variations. Consequently, the spatial phase of an electromagnetic wave remains uniform over macroscopic distances, fundamentally transforming how light propagates and interacts with physical structures. (Wu et al., 2021)

This research direction bridges foundational electromagnetics and advanced material science. By neutralizing the spatial phase accumulation of light, NZI media allow for the exploration of extreme optical regimes and wave phenomena that cannot be observed in conventional dielectric or metallic environments.

significance & applications

Operating in the near-zero-index regime unlocks unprecedented control over electromagnetic fields, offering a versatile platform for shaping wave fronts and enhancing quantum processes. The potential applications are highly disruptive, spanning shape-independent optical tunneling, highly efficient nonlinear optical frequency conversion, large-area single-mode coherent emission, and ultra-compact optical logic components for advanced computing and telecommunications.

research focus

new phenomena and mechanisms: investigating novel wave physics and unique light-matter interaction regimes that emerge exclusively within zero-index environments. (e.g., (Wu et al., 2021; Wu† et al., 2022; Wu* et al., 2024; Wu* et al., 2025; Wu*† et al., 2026))
advanced micro- and nano-fabrication: developing high-precision lithography and etching methodologies to realize intricate metamaterial structures possessing tailored near-zero-index properties. (e.g., (Wu et al., 2021; Huang et al., 2023))
advanced device design: engineering innovative photonic components that leverage spatially uniform phases to achieve non-traditional and extreme optical functionalities. (e.g., (Xie et al., 2020; Sha et al., 2021; Sha et al., 2022; Xie et al., 2022))
advanced on-chip integration: integrating near-zero-index architectures onto standard photonic platforms to enable scalable, multi-functional, and high-density optical circuits. (e.g., (Sha et al., 2022; Wu* et al., 2024), also see project: integrated photonic devices and chips
advanced packaging processes: establishing robust, low-loss, and excellent thermal management packaging solutions to ensure long-term environmental stability and reliable optical coupling for integrated near-zero-index systems. (e.g., (Wu et al., 2021; Wu* et al., 2024))

Near-zero-index photonic media: fabrication, prerequisite studies, new phenomena, and applications.

We also aim to develop and introduce new techniques (Wu et al., 2021; Wang et al., 2021; Huang et al., 2022) in a multi- and inter-disciplinary way, and are active on theories, simulations, and experiments (Wu et al., 2021; Wu et al., 2020; Wu* et al., 2024; Wu* et al., 2025).

References

2026

Thermo-optic dynamics of effective epsilon-near-zero media

Jiaye Wu^*†, Xuanyi Liu^†, Marco Clementi, Shuang Qiu, Limin Lin, Zhang-Kai Zhou^*, and Camille-Sophie Brès^*

arXiv preprint, Apr 2026

DOI arXiv Bib HTML

@article{Wu2026,
  title = {{Thermo-optic dynamics of effective epsilon-near-zero media}},
  author = {Wu, Jiaye and Liu, Xuanyi and Clementi, Marco and Qiu, Shuang and Lin, Limin and Zhou, Zhang-Kai and Br{\`e}s, Camille-Sophie},
  year = {2026},
  month = apr,
  journal = {arXiv preprint},
  volume = {0},
  number = {0},
  pages = {0},
  issn = {0-0},
  doi = {10.48550/arXiv.2604.25656},
  lccn = {1},
}

2025

Intracavity Epsilon-Near-Zero Dual-Range Frequency Switch

Jiaye Wu^*, Gang Wang, Marco Clementi, Ji Zhou, Chenxingyu Huang, Xuanyi Liu, H. Y. Fu, Qian Li, and Camille-Sophie Brès^*

ACS Photonics, Mar 2025

Featured Journal Cover Art DOI Bib HTML

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@article{Wu2025,
  title = {Intracavity Epsilon-Near-Zero Dual-Range Frequency Switch},
  author = {Wu, Jiaye and Wang, Gang and Clementi, Marco and Zhou, Ji and Huang, Chenxingyu and Liu, Xuanyi and Fu, H. Y. and Li, Qian and Br{\`e}s, Camille-Sophie},
  year = {2025},
  month = mar,
  journal = {ACS Photonics},
  volume = {12},
  number = {3},
  pages = {1276--1283},
  issn = {2330-4022},
  doi = {10.1021/acsphotonics.4c01322},
  lccn = {1},
}

2024

Thermo-optic epsilon-near-zero effects

Jiaye Wu^*, Marco Clementi, Chenxingyu Huang, Feng Ye, Hongyan Fu, Lei Lu, Shengdong Zhang, Qian Li^*, and Camille-Sophie Brès^*

Nature Communications, Jan 2024

DOI Bib HTML Blog

@article{Wu2024a,
  title = {Thermo-optic epsilon-near-zero effects},
  author = {Wu, Jiaye and Clementi, Marco and Huang, Chenxingyu and Ye, Feng and Fu, Hongyan and Lu, Lei and Zhang, Shengdong and Li, Qian and Br{\`e}s, Camille-Sophie},
  year = {2024},
  month = jan,
  journal = {Nature Communications},
  volume = {15},
  number = {1},
  pages = {794},
  issn = {2041-1723},
  doi = {10.1038/s41467-024-45054-z},
  lccn = {1},
}

2023

Manufacturing-Enabled Tunability of Linear and Nonlinear Epsilon-Near-Zero Properties in Indium Tin Oxide Nanofilms

Chenxingyu Huang, Siwei Peng, Xuanyi Liu, Jiaye Wu, Hongyan Fu, Lei Lu, Shengdong Zhang, and Qian Li^*

ACS Applied Materials & Interfaces, Jul 2023

DOI Bib HTML

@article{Huang2023,
  title = {{Manufacturing-Enabled Tunability of Linear and Nonlinear Epsilon-Near-Zero Properties in Indium Tin Oxide Nanofilms}},
  author = {Huang, Chenxingyu and Peng, Siwei and Liu, Xuanyi and Wu, Jiaye and Fu, Hongyan and Lu, Lei and Zhang, Shengdong and Li, Qian},
  year = {2023},
  month = jul,
  journal = {ACS Applied Materials \& Interfaces},
  volume = {15},
  number = {29},
  pages = {35186--35195},
  issn = {1944-8244},
  doi = {10.1021/acsami.3c06270},
  lccn = {2},
}

2022

Observation of SQUID-Like Behavior in Fiber Laser with Intra-Cavity Epsilon-Near-Zero Effect

Jiaye Wu^†, Xuanyi Liu^†, Boris A. Malomed, Kuan-Chang Chang, Minghe Zhao, Kang Qi, Yanhua Sha, Ze Tao Xie, Marco Clementi, Camille-Sophie Brès, Shengdong Zhang, Hongyan Fu^*, and Qian Li^*

Laser & Photonics Reviews, Dec 2022

DOI arXiv Bib HTML

@article{Wu2022,
  title = {{Observation of SQUID-Like Behavior in Fiber Laser with Intra-Cavity Epsilon-Near-Zero Effect}},
  author = {Wu, Jiaye and Liu, Xuanyi and Malomed, Boris A. and Chang, Kuan-Chang and Zhao, Minghe and Qi, Kang and Sha, Yanhua and Xie, Ze Tao and Clementi, Marco and Br{\`e}s, Camille-Sophie and Zhang, Shengdong and Fu, Hongyan and Li, Qian},
  year = {2022},
  month = dec,
  journal = {Laser \& Photonics Reviews},
  volume = {16},
  number = {12},
  pages = {2200487},
  issn = {1863-8880},
  doi = {10.1002/lpor.202200487},
  lccn = {1},
}

All-optical switching in epsilon-near-zero asymmetric directional coupler

Yanhua Sha, Ze Tao Xie, Jiaye Wu, H. Y. Fu, and Qian Li^*

Scientific Reports, Oct 2022

DOI Bib HTML

@article{Sha2022,
  title = {All-optical switching in epsilon-near-zero asymmetric directional coupler},
  author = {Sha, Yanhua and Xie, Ze Tao and Wu, Jiaye and Fu, H. Y. and Li, Qian},
  year = {2022},
  month = oct,
  journal = {Scientific Reports},
  volume = {12},
  number = {1},
  pages = {17958},
  issn = {2045-2322},
  doi = {10.1038/s41598-022-22573-7},
  lccn = {2},
}

Ultrafast dynamic switching of optical response based on nonlinear hyperbolic metamaterial platform

Ze Tao Xie, Yanhua Sha, Jiaye Wu, H. Y. Fu, and Qian Li^*

Optics Express, Jun 2022

DOI Bib HTML

@article{Xie2022,
  title = {Ultrafast dynamic switching of optical response based on nonlinear hyperbolic metamaterial platform},
  author = {Xie, Ze Tao and Sha, Yanhua and Wu, Jiaye and Fu, H. Y. and Li, Qian},
  year = {2022},
  month = jun,
  journal = {Optics Express},
  volume = {30},
  number = {12},
  pages = {21634--21648},
  issn = {1094-4087},
  doi = {10.1364/OE.457875},
  lccn = {2},
}

Pulse interactions in periodic and genetic-algorithm-optimized aperiodic epsilon-near-zero multilayers

Chenxingyu Huang, Jiaye Wu, Yuqing Wang, Zimiao Wang, H. Y. Fu, and Qian Li^*

Journal of the Optical Society of America B, Jan 2022

DOI Bib HTML

@article{Huang2022,
  title = {Pulse interactions in periodic and genetic-algorithm-optimized aperiodic epsilon-near-zero multilayers},
  author = {Huang, Chenxingyu and Wu, Jiaye and Wang, Yuqing and Wang, Zimiao and Fu, H. Y. and Li, Qian},
  year = {2022},
  month = jan,
  journal = {Journal of the Optical Society of America B},
  volume = {39},
  number = {1},
  pages = {258--265},
  issn = {0740-3224},
  doi = {10.1364/JOSAB.444596},
}

2021

Epsilon-near-zero photonics: Infinite potentials

Jiaye Wu, Ze Tao Xie, Yanhua Sha, H. Y. Fu, and Qian Li^*

Photonics Research, Aug 2021

DOI Bib HTML

@article{Wu2021,
  title = {Epsilon-near-zero photonics: {{Infinite}} potentials},
  author = {Wu, Jiaye and Xie, Ze Tao and Sha, Yanhua and Fu, H. Y. and Li, Qian},
  year = {2021},
  month = aug,
  journal = {Photonics Research},
  volume = {9},
  number = {8},
  pages = {1616--1644},
  issn = {2327-9125},
  doi = {10.1364/PRJ.427246},
  lccn = {1},
}

Numerical investigations on the cascaded high harmonic and quasi-supercontinuum generations in epsilon-near-zero aluminum-doped zinc oxide nanolayers

Jiaye Wu, Ze Tao Xie, H.Y. Fu, and Qian Li^*

Results in Physics, May 2021

DOI Bib HTML

@article{Wu2021a,
  title = {Numerical investigations on the cascaded high harmonic and quasi-supercontinuum generations in epsilon-near-zero aluminum-doped zinc oxide nanolayers},
  author = {Wu, Jiaye and Xie, Ze Tao and Fu, H.Y. and Li, Qian},
  year = {2021},
  month = may,
  journal = {Results in Physics},
  volume = {24},
  pages = {104086},
  issn = {22113797},
  doi = {10.1016/j.rinp.2021.104086},
  lccn = {2},
}

Manipulation of epsilon-near-zero wavelength for the optimization of linear and nonlinear absorption by supercritical fluid

Jiaye Wu, Xuanyi Liu, Haishi Fu, Kuan-Chang Chang, Shengdong Zhang, H. Y. Fu, and Qian Li^*

Scientific Reports, Dec 2021

DOI Bib HTML

@article{Wu2021b,
  title = {Manipulation of epsilon-near-zero wavelength for the optimization of linear and nonlinear absorption by supercritical fluid},
  author = {Wu, Jiaye and Liu, Xuanyi and Fu, Haishi and Chang, Kuan-Chang and Zhang, Shengdong and Fu, H. Y. and Li, Qian},
  year = {2021},
  month = dec,
  journal = {Scientific Reports},
  volume = {11},
  number = {1},
  pages = {15936},
  issn = {2045-2322},
  doi = {10.1038/s41598-021-95513-6},
  lccn = {2},
}

Comparison Study of Multi-Slot Designs in Epsilon-Near-Zero Waveguide-Based Electro-Optical Modulators

Yanhua Sha, Jiaye Wu, Ze Tao Xie, H. Y. Fu, and Qian Li^*

IEEE Photonics Journal, Jun 2021

DOI Bib HTML

@article{Sha2021,
  title = {{Comparison Study of Multi-Slot Designs in Epsilon-Near-Zero Waveguide-Based Electro-Optical Modulators}},
  author = {Sha, Yanhua and Wu, Jiaye and Xie, Ze Tao and Fu, H. Y. and Li, Qian},
  year = {2021},
  month = jun,
  journal = {IEEE Photonics Journal},
  volume = {13},
  number = {3},
  pages = {1--12},
  issn = {1943-0655},
  doi = {10.1109/JPHOT.2021.3084943},
  lccn = {4},
}

Optimization of Epsilon-Near-Zero Multilayers for Near-Perfect Light Absorption Using an Enhanced Genetic Algorithm

Yuqing Wang, Jiaye Wu, Zimiao Wang, Chenxingyu Huang, H. Y. Fu, and Qian Li^*

IEEE Photonics Journal, Oct 2021

DOI Bib HTML

@article{Wang2021,
  title = {{Optimization of Epsilon-Near-Zero Multilayers for Near-Perfect Light Absorption Using an Enhanced Genetic Algorithm}},
  author = {Wang, Yuqing and Wu, Jiaye and Wang, Zimiao and Huang, Chenxingyu and Fu, H. Y. and Li, Qian},
  year = {2021},
  month = oct,
  journal = {IEEE Photonics Journal},
  volume = {13},
  number = {5},
  pages = {1--10},
  issn = {1943-0655},
  doi = {10.1109/JPHOT.2021.3113924},
  lccn = {4},
}

2020

Tunable Electro- and All-Optical Switch Based on Epsilon-Near-Zero Metasurface

Ze Tao Xie, Jiaye Wu, H. Y. Fu, and Qian Li^*

IEEE Photonics Journal, Aug 2020

DOI Bib HTML

@article{Xie2020a,
  title = {{Tunable Electro- and All-Optical Switch Based on Epsilon-Near-Zero Metasurface}},
  author = {Xie, Ze Tao and Wu, Jiaye and Fu, H. Y. and Li, Qian},
  year = {2020},
  month = aug,
  journal = {IEEE Photonics Journal},
  volume = {12},
  number = {4},
  pages = {1--10},
  issn = {1943-0655},
  doi = {10.1109/JPHOT.2020.3010284},
  lccn = {4},
}

Comparative study on epsilon-near-zero transparent conducting oxides: High-order chromatic dispersions and modeling of ultrashort pulse interactions

Jiaye Wu, Ze Tao Xie, Yanhua Sha, H. Y. Fu, and Qian Li^*

Physical Review A, Nov 2020

DOI Bib HTML

@article{Wu2020a,
  title = {Comparative study on epsilon-near-zero transparent conducting oxides: {{High-order}} chromatic dispersions and modeling of ultrashort pulse interactions},
  author = {Wu, Jiaye and Xie, Ze Tao and Sha, Yanhua and Fu, H. Y. and Li, Qian},
  year = {2020},
  month = nov,
  journal = {Physical Review A},
  volume = {102},
  number = {5},
  pages = {053503},
  issn = {2469-9926},
  doi = {10.1103/PhysRevA.102.053503},
  lccn = {2},
}