Phys.org August 25, 2022
One of the key insights of non-Hermitian photonics is that well-established concepts such as the laser can be operated in reverse to realize a coherent perfect absorber (CPA). Although conceptually appealing, such CPAs are limited so far to a single, judiciously shaped wavefront or mode. An international team of researchers (Israel, Austria) built a “light trap” around the thin layer using mirrors and lenses, in which the light beam is steered in a circle and then superimposed on itself—exactly in such a way that the beam of light blocks itself and can no longer leave the system. Thus, the light has no choice but to be absorbed by the thin layer. Placing a weak, critically coupled absorber into this cavity, any incoming wavefront, even a complex and dynamically varying speckle pattern, is absorbed with close to perfect efficiency in a massively parallel interference process. These characteristics open interesting new possibilities for applications in light harvesting, energy delivery, light control, and imaging…read more. TECHNICAL ARTICLE
The “light trap” setup is shown, consisting of a partially transparent mirror, a thin, weak absorber, two converging lenses and a totally reflecting mirror…Credit: TU Wien