Near-Unity Absorption in Semiconductor Metasurfaces Using Kerker Interference

The ability to detect light with high efficiency is an important device metric for single-photon detectors and cameras, essential for applications ranging from quantum communication to biomedical imaging. However, these photodetectors have limited detection efficiency in the 850-1100 nm wavelength range, known as the 'valley of death'. Here, we demonstrate a near-perfect absorber in the 'valley of death' using a semiconductor metasurface with spectral and spatial selectivity on a high refractive index substrate. Our design leverages higher order optical modes of InGaAs resonators to generate Kerker interference at the target wavelength of 920 nm, which leads to a measured peak absorption efficiency of ∼94%. In addition, numerical calculations show that our design enables spatial control of the absorption profile within the resonators, which is promising for improving response time. Our approach offers tunability over a desired spectral range and paves the way for development of high-performance photodetectors.