Breaking the fundamental scattering limit with gain metasurfaces

• DOI: 10.1038/s41467-022-32067-9
• Publication Date: 2022-07-28T14:09:55Z
• Authors: Chao Qian; Yi Yang; Yifei Hua; Chan Wang; Xiao Lin; Tong Cai; Dexin Ye; Erping Li; Ido Kaminer; Hongsheng Chen
• Keywords: Science; Q; 0103 physical sciences; 02 engineering and technology; 0210 nano-technology; 01 natural sciences; 7. Clean energy; Article

A long-held tenet in physics asserts that particles interacting with light suffer from a fundamental limit to their scattering cross section, referred as the single-channel limit. This notion, appearing all one, two, and three dimensions, severely limits interaction strength between types of passive resonators photonic environments thus constrains plethora applications bioimaging, sensing, photovoltaics. Here, we propose route overcome this by exploiting gain media. We show when an excited resonance is critically coupled desired channel, arbitrarily large section can be achieved principle. From transient analysis, explain formation relaxation phenomenon compare it degeneracy-induced multi-channel superscattering, whose temporal behaviors have been usually overlooked. To experimentally test our predictions, design two-dimensional resonator encircled metasurfaces incorporating negative- resistance components demonstrate exceeds single- channel more than 40-fold. Our findings verify possibility stronger beyond herald novel class light-matter interactions enabled metasurfaces.