This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Researchers have demonstrated that a naturally occurring mineral can serve as a low-loss optical material for next-generation broadband all–van der Waals nanophotonic components. Muscovite, also known as mica, is a van der Waals mineral widely found in rocks and used in a range of industrial applications, yet it may prove to have an unexpected role in the future of nanophotonic components.
Researchers from the Institute of Physics at Yerevan State University and the Institute for Functional Intelligent Materials at National University of Singapore have demonstrated that muscovite, a layered van der Waals material, combines an unusually low refractive index with extremely low optical losses across a wide ultraviolet-to-near-infrared spectral region. Their findings, published in Advanced Optical Materials, show that muscovite provides a key missing element for building all–van der Waals ultrathin photonic devices. The team tackled this problem by determining the optical constants of muscovite over a broad spectral region, spanning wavelengths from 250 to 1,700 nm.
Using spectroscopic micro-ellipsometry, they characterized muscovite's anisotropic dielectric response and found that it maintains a low refractive index and negligible absorption throughout the investigated spectral region. They further showed that the material exhibits weak in-plane birefringence, which can be neglected in the thin-layer limit (< 250 nm). These properties make muscovite particularly attractive as a low-index optical layer—a role that has been largely missing in the broader family of layered van der Waals materials.
The researchers then demonstrated how muscovite can be combined with the high-index van der Waals material molybdenum disulfide (MoS₂) to create next-generation functional nanophotonic components. The unprecedented refractive-index contrast between them enables efficient control of light through optical interference. Using these two complementary building blocks, the team engineered all–van der Waals distributed Bragg reflectors (DBRs) and short-pass dichroic beam splitters (DSBs) operating in the near-infrared (NIR) spectral region.
The resulting devices are remarkably thin. A five-layer DBR, with a total thickness of just 650 nm, achieves an average broadband reflection exceeding 95% at wavelengths above 1,100 nm. Similarly, the short-pass DBS is only 690 nm thick while achieving an average transmission of 98% across the 990–1,040 nm spectral region and maintaining similarly high reflection at wavelengths from 1,240 to 1,700 nm.
Hayrapetyan et al, Dielectric Permittivity Tensor of Muscovite for Next Generation All Van Der Waals Broadband Photonic Components, Advanced Optical Materials (2026). Journal information: Advanced Optical Materials MA in English, copy editor since 2021 with experience in higher education and health content. Dedicated to trustworthy science news.
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