Cusworth Emma, Ho Shermine, Kravets Vasyl G, Ong Bin Leong, Rusydi Andrivo, Novoselov Kostya S, Grigorenko Alexander N
Opt Express. 2024 May 6;32(10):17922-17931. doi: 10.1364/OE.522045.
Miniaturization of optical devices is a modern trend essential for optoelectronics, optical sensing, optical computing and other branches of science and technology. To satisfy this trend, optical materials with a small footprint are required. Here we show that extremely thin, flat, nanostructured gold films made of highly oriented single-crystalline gold quantum-dots can provide elements of topological photonics in visible light and be used as high-index dielectric materials in the infrared part of the spectra. We measure and theoretically confirm the presence of topological darkness and associated phase singularities in studied gold films of thickness of below 10 nm placed on MgO substrates in the red part of the spectrum. At telecom wavelengths, the fabricated gold metasurface behaves as a dielectric with the refractive index of n≈2.75 and the absorption coefficient of k≈0.005.
光学器件的小型化是光电子学、光学传感、光学计算以及其他科技分支的现代发展趋势。为顺应这一趋势，需要占用空间小的光学材料。在此我们表明，由高度取向的单晶金量子点制成的极薄、扁平的纳米结构金膜可在可见光中提供拓扑光子学元件，并在光谱的红外部分用作高折射率介电材料。我们测量并从理论上证实，在光谱的红色部分，置于氧化镁衬底上厚度低于10纳米的金膜中存在拓扑暗态及相关的相位奇点。在电信波长下，所制备的金超表面表现为一种介电材料，其折射率n≈2.75，吸收系数k≈0.005。
