Van der Waals (vdW) crystals supporting in-plane anisotropic hyperbolic phonon polaritons (HPhPs) provide a promising route toward mid-infrared (MIR) and terahertz (THz) nanophotonics by enabling deep-subwavelength confinement, low-loss propagation, and directional control of light within the crystal plane. Although such anisotropic HPhPs have been reported in a few vdW crystals, most studies have relied on bulk crystals or mechanically exfoliated flakes, which limits scalability and compatibility with device fabrication. At present, α-MoO₃ is essentially the only vdW material available as large-area nanoflakes for fabrication-ready anisotropic polaritonic structures. Here, we demonstrate the scalable physical vapor deposition (PVD) growth of free-standing, monocrystalline α-V₂O₅ nanoflakes with lateral dimensions up to hundreds of micrometers and thicknesses down to a few nanometers. Using infrared nano-imaging together with theoretical analysis, we uncover low-loss in-plane anisotropic HPhPs in α-V₂O₅ with strong confinement (λ₀/λ ≈ 100), ultraslow group velocities (~3×10^-4c), and lifetimes up to 9 ps. We further show that patterned microdisk cavities enable geometry-defined shaping of the polaritonic near field, allowing tailored in-plane electromagnetic confinement. Our results establish α-V₂O₅ as a large-area, monocrystalline, fabrication-ready vdW material for low-loss anisotropic polaritonics, and expand the materials basis for scalable infrared flat photonics and future on-chip polaritonic devices.

Electromagnetic interference (EMI) shielding in high-frequency range, especially the rapidly growing terahertz (THz) frequency range, attracts increasing attention due to the potential application of terahertz in 6G wireless communication, and security inspection. However, traditional conductive EMI films typically achieve high shielding effectiveness through strong reflection, which may cause secondary pollution to other devices. Here, a gradient structure strategy was proposed to construct Ti₃C₂T_x/hydroxypropyl methyl cellulose (HPMC) film, in which the content of Ti₃C₂T_x gradually increases along the thickness direction, resulting in different conductivity of the two surfaces (surface-M and surface-H) for the film. The obtained gradient-film exhibits an EMI shielding efficiency of over 48.5 dB in the THz range (0.2–1.6 THz) at a thickness of 40 μm. Especially, as the THz waves incident from the surface-H to the film, the absorption effectiveness reaches 48.2 dB (average absorbed power loss up to 91.4%), and the reflection effectiveness is only 0.3 dB. In additions, the gradient-film also demonstrates a high absorption rate of 95.5% in the infrared band (2.5–16.7 μm). Moreover, the gradient-film exhibits an excellent tensile stress and Young’s modulus value of 173.1 MPa and 2.8 GPa, respectively. Therefore, the gradient-film proposed in this work, with excellent electromagnetic absorption in both THz and infrared band, provides a promising candidate for the next-generation EMI shielding applications.