Perfect Absorption in a Disordered Medium with Programmable Meta‐Atom Inclusions
Mohammadreza F. Imani, David R. Smith, Philipp del Hougne
Abstract
Abstract Achieving the very special condition of perfect absorption (PA) in a complex scattering enclosure promises to enable a wealth of applications in secure communication, precision sensing, wireless power transfer, analog signal processing, and random lasing. Consequently, a lot of recent research effort is dedicated to proposing wave‐front shaping protocols to implement coherent PA in complex scattering environments with tunable localized absorption as well as a tunable excitation frequency. Here, the conceptually different route of solely tweaking the randomness of the complex scattering environment in order to achieve PA is proposed. An experimental proof‐of‐concept in the microwave domain is provided where the randomness of a 3D chaotic cavity is tuned with programmable meta‐atom inclusions. The achievability and extreme sensitivity of the PA condition are systematically investigated. The presented technique can impose a PA condition at over hundred distinct frequencies within a small frequency band, enabling the proposal and experimental demonstration of a concrete practical application: receiver‐powered secure wireless communication in a complex scattering enclosure. The presented fundamentally new perspective on PA applies to all types of wave phenomena; the experimental results foreshadow the large potential of this novel tool for minute wave control in sensing, communication, and energy transfer.