Nonreflector

Nonreflector is a term used to describe a surface, material, or boundary condition designed to minimize or eliminate the reflection of waves. It is not a standard technical term with a single definition, but in practice it encompasses anti-reflective and absorbing technologies across optics, acoustics, and computational modeling.

Optical nonreflectors aim to reduce Fresnel reflections at interfaces such as air-glass or air-lens. Common approaches include anti-reflective coatings, which use thin-film interference to match refractive indices, and multilayer dielectric stacks that extend the bandwidth; bio-inspired solutions such as moth-eye nanostructures provide broadband suppression.

Acoustic nonreflectors use impedance-matching materials and porous structures to absorb incident sound, reducing reflections in rooms, vehicles, or enclosures. Porous foams, fibrous materials, and microperforated panels are typical solutions.

In computational physics, nonreflecting or absorbing boundary conditions prevent artificial reflections from the edges of a simulated domain. Techniques include Sommerfeld radiation conditions and perfectly matched layers (PML).

Limitations include bandwidth, angular dependence, cost, and physical constraints; no perfect nonreflection over all frequencies and directions. Real-world nonreflectors aim for acceptable performance within operational ranges.