Ученые создали гибкое стекло, прозрачное для инфракрасного излучения до 21 мкм

Researchers have developed a chalcogenide glass that achieves broad IR transparency up to 21 μm and polymer-like mechanical flexibility for advanced adaptive optics applications. The material is infrared-transparent and ultra-flexible, designed with a novel chain-ring dual-network architecture. Their findings were published in Light: Science & Applications. IR Transparency-Flexibility Challenge The development of transparent, flexible inorganic-organic composite materials is critical for advancing adaptive optics, bio-integrated sensing, and reconfigurable photonics. However, a long-standing challenge in optics is creating materials that combine both broad-spectrum infrared (IR) transparency and high mechanical flexibility. Typically, materials that offer wide IR transmission require rigid, heavy-element-based three-dimensional networks to minimize vibrational absorption, resulting in brittle behavior and high Young’s moduli (~100 GPa). Conversely, flexible materials such as polymers exhibit low stiffness but strong IR absorption, limiting their use in IR optical applications. Existing materials, including flexible chalcogenides, ultrathin polymer films, and sulfur-based hybrids, have not effectively bridged this trade-off, inhibiting the implementation of compact, high-performance adaptive optical systems operating across the IR regime. The urgency of this problem is particularly pronounced in fields such as space-based laser communication, high-resolution IR surveillance, laser machining, and biomedical imaging, where adaptive optics require real-time, precise wavefront correction under mechanical stress. Synthesis and Characterization Techniques To overcome the inherent optical-mechanical conflict, the authors designed an infrared ultra-flexible chalcogenide glass with the composition S60Se40 (IR-FCh-60) that exhibits a novel chain-ring dual-network (DN) architecture. This architecture synergistically integrates covalent chains made from heavy chalcogen elements (sulfur and selenium) with physically cross-linked ring domains. The covalent [Se, S]n chains suppress multi-phonon vibration absorption, ensuring broadband IR transparency up to 21 μm, while the physically cross-linked rings provide dynamic cross-links that enable ultralow modulus and high flexibility. This dual-network design incorporates dynamic covalent bonds (S–S, Se–Se, Se–S) that promote autonomous self-healing and shape-memory behavior at room temperature. Synthesis involved vacuum melt-quenching of high-purity sulfur and selenium in quartz tubes under vacuum, heated to 673 K for 48 hours to homogenize, followed by water quenching to form glass ingots. Wafers were cut and polished for optical quality. Structural characterization was performed using micro-Raman spectroscopy and Fourier-transform IR spectroscopy, while refractive dispersion was measured via ellipsometry. Mechanical properties were evaluated through tension, compression, three-point bending, and dynamic mechanical analysis under ambient conditions. Molecular dynamics simulations were performed using Materials Studio and LAMMPS to model the atomic structure and simulate tensile deformation, revealing the reversible behavior of molecular chains and rings during strain. Dual-Network Glass Properties The IR-FCh-60 glass surpasses the classical trade-off between IR transparency and flexibility. It demonstrates IR transmission from 0.62 to 21 μm, encompassing crucial atmospheric windows (3–5 μm and 8–14 μm). Download a PDF copy of this page! This far exceeds typical polymers (PMMA, PDMS, PU), which become opaque beyond 2.5–6.5 μm, and even surpasses many commercial IR glasses and fluoride crystals, which cut off around 6–13 μm. Remarkably, the material maintains this transmission after one year in ambient conditions and under repeated mechanical deformation cycles, indicating excellent optical stability. Mechanically, IR-FCh-60 exhibits a dramatically low Young’s modulus (~0.0037 GPa), comparable to soft polymers but with a tensile strain capacity near 650%. It recovers elastically (~80%) over a broad strain range (25–400%), outperforming conventional high-modulus optical polymers, which undergo plastic deformation under strain. The low interchain friction and dynamic physical bonding between ring and chain domains facilitate reversible elongation and slippage, contributing to exceptional mechanical compliance without sacrificing structural integrity. This polymer-like mechanical behavior with glass-like IR transparency is unique among optical materials. Dynamic Raman spectrometry and molecular simulations reveal that the glass network’s elasticity arises from reversible elongation and reconfiguration of Se–Se and related bonds, key to accommodating strain while preserving optical properties. The physically cross-linked rings act as dynamic topological junctions that dissipate energy under stress yet maintain connectivity. The dynamic covalent bonds confer autonomous room-temperature self-healing and shape memory, enhancing the material’s robustness compared to brittle inorganic glasses or IR-opaque polymers. Cyclic stretching experiments indicate minimal hysteresis in IR transmittance across wavelengths (850 nm to 10.6 μm), underscoring excellent optomechanical stability during deformation cycles. To demonstrate practical applicability, the authors fabricated infrared deformable lenses (IR-DLs) using IR-FCh-60. These lenses exhibit tunable focal lengths and real-time wavefront aberration correction under moderate mechanical actuation, capabilities unattainable with conventional rigid IR materials or strongly absorbing flexible polymers. Implications for Adaptive Optics This research establishes a new class of infrared optical materials that seamlessly integrate glass-like broad IR transparency with polymer-like mechanical flexibility. By pioneering a chain-ring dual-network architecture based on heavy chalcogen elements, the IR-FCh-60 glass addresses the longstanding material challenge in flexible IR optics. It achieves an unprecedented combination of ultralow Young’s modulus, extreme strain capacity, self-healing ability, and durable optical transmission up to 21 μm, suitable for adaptive optics applications requiring dynamic wavefront tuning and robust mechanical deformations. This novel material platform opens promising avenues in infrared adaptive optics, biomedical imaging, and compact photonic devices, enabling next-generation reconfigurable and soft IR optical systems that were previously beyond reach. Journal Reference Li, S., Tan, L., et al. (2026). An infrared-transparent flexible glass for adaptive optics. Light: Science & Applications. 15. DOI: 10.1038/s41377-026-02409-z. https://www.nature.com/articles/s41377-026-02409-z.