2021/06/23 by Zhaogang Dong, Lei Jin, Dong, Zhaogang +22 · 1 citation
Computer Science · Engineering · Physics and Astronomy · #Applied Physics (physics.app-ph) #FOS: Physical sciences #Neural Networks and Reservoir Computing #Optics (physics.optics) #Photonic and Optical Devices #Quantum-Dot Cellular Automata #physics.app-ph #physics.optics
paper · pdf · doi:10.48550/arxiv.2106.12285
40 pages, 4 figures in the main text, 15 figures in the supplementary information
arxiv created 2021/06/23 · openalex publication_date 2021/06/23 · arxiv updated 2021/06/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
While structural colors are ubiquitous in nature, saturated reds are mysteriously absent. Hence, a longstanding problem is in fabricating nanostructured surfaces that exhibit reflectance approaching the theoretical limit. This limit is termed the Schrodinger red and demands sharp spectral transitions from "stopband" to a high reflectance "passband" with total suppression of higher-order resonances at blue and green wavelengths. Current approaches based on metallic or dielectric nanoantennas are insufficient to simultaneously meet these conditions. Here, for the 1st time, we designed and fabricated tall Si nanoantenna arrays on quartz substrate to support two partially overlapping y polarized quasi bound-state-in-the-continuum (q-BIC) modes in the red wavelengths with sharp spectral edges. These structures produce possibly the most saturated and brightest reds with ~80% reflectance, exceeding the red vertex in sRGB and even the cadmium red pigment. We employed a gradient descent algorithm with structures supporting q BIC as the starting point. Although the current design is polarization dependent, the proposed paradigm has enabled us to achieve the elusive structural red and the design principle could be generalized to Schrodinger's pixels of other colors. The design is suitable for scale up using other nanofabrication techniques for larger area applications, such as red pixels in displays, decorative coatings, and miniaturized spectrometers with high wavelength selectivity.