Controlling light emission and detection using subwavelength interlayers

Light emission and detection are basic processes at the core of applications in optics and photonics, such as lighting, sensing and telecom. Despite extensive work on the design of light-matter interfaces, the exchange of electromagnetic radiation with matter is still a challenge. Here, we show how subwavelength interlayers can lead to light outcoupling efficiencies approaching 100% in combination with strong directional emission, specifically from materials with a large refractive index. We also highlight potentials for enhanced light detection and control, via structural reciprocity. Our findings are particularly relevant for semiconductor-based nanophotonic devices, which typically suffer from a large mismatch with respect to free-space and guided modes.