Objects invisible from multiple directions

The first proposed invisibility cloaks required materials that are highly anisotropic, spatially inhomogeneous, and that possess a magnetic response. These properties are still difficult or impractical to achieve in practice, leading many researchers to explore simplified invisibility schemes that trade perfection for simplicity in design. In this paper, we investigate a traditional method by Devaney for constructing multi-angle invisibility devices, i.e., devices that are invisible for a finite number of directions of illumination in the weak scattering limit. We demonstrate that the scattering cross-section of these objects decreases dramatically as the number of invisibility directions is increased.