Anti-Hermitian photodetector facilitating efficient subwavelength photon sorting

• Published in: Nature communications 2018-01, Vol.9 (1), p.316-7, Article 316
• Main Authors: Kim, Soo Jin, Kang, Ju-Hyung, Mutlu, Mehmet, Park, Joonsuk, Park, Woosung, Goodson, Kenneth E., Sinclair, Robert, Fan, Shanhui, Kik, Pieter G., Brongersma, Mark L.
• Format: Article
• Language: English
• Subjects: 639/624/399/1015; 639/766/1130/2799; 639/925/927/1021; Biosensors; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Electric fields; Electrical engineering; electrodes - solar; Energy harvesting; ENGINEERING; Humanities and Social Sciences; Incident light; Light; materials and chemistry by design; MATERIALS SCIENCE; Microscopy; multidisciplinary; optics; Optoelectronic devices; phonons; Photoelectric effect; Photoelectric emission; Photometers; Photons; Photovoltaic cells; Photovoltaics; Science; Science (multidisciplinary); solar (photovoltaic); Solar cells; solid state lighting; Spectra; Spectral control; Spectral sensitivity; Spectrum analysis; synthesis (novel materials); synthesis (self-assembly); thermal conductivity; Unity; Wavelength; Wavelengths
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-017-02496-y

The ability to split an incident light beam into separate wavelength bands is central to a diverse set of optical applications, including imaging, biosensing, communication, photocatalysis, and photovoltaics. Entirely new opportunities are currently emerging with the recently demonstrated possibility to spectrally split light at a subwavelength scale with optical antennas. Unfortunately, such small structures offer limited spectral control and are hard to exploit in optoelectronic devices. Here, we overcome both challenges and demonstrate how within a single-layer metafilm one can laterally sort photons of different wavelengths below the free-space diffraction limit and extract a useful photocurrent. This chipscale demonstration of anti-Hermitian coupling between resonant photodetector elements also facilitates near-unity photon-sorting efficiencies, near-unity absorption, and a narrow spectral response (∼ 30 nm) for the different wavelength channels. This work opens up entirely new design paradigms for image sensors and energy harvesting systems in which the active elements both sort and detect photons. Subwavelength photon sorting in photodetection systems with a narrow spectral bandwidth has remained elusive. The authors spectrally sort and detect photons by suppressing the near-field interaction and maximizing the far-field interactions between photodetector elements, achieving a spectral separation of 30 nm.