Chernow Victoria F, Ng Ryan C, Peng Siying, Atwater Harry A, Greer Julia R
Division of Engineering and Applied Sciences, California Institute of Technology, Pasadena, California 91125, United States.
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States.
Nano Lett. 2021 Nov 10;21(21):9102-9107. doi: 10.1021/acs.nanolett.1c02851. Epub 2021 Oct 21.
Engineering of the dispersion properties of a photonic crystal (PhC) opens a new paradigm for the design and function of PhC devices. Exploiting the dispersion properties of PhCs allows control over wave propagation within a PhC. We describe the design, fabrication, and experimental observation of photonic bands for 3D PhCs capable of negative refraction in the mid-infrared. Band structure and equifrequency contours were calculated to inform the design of 3D polymer-germanium core-shell PhCs, which were fabricated using two-photon lithography direct laser writing and sputtering. We successfully characterized a polymer-Ge core-shell lattice and mapped its band structure, which we then used to calculate the PhC refraction behavior. An analysis of wave propagation revealed that this 3D core-shell PhC refracts light negatively and possesses an effective negative index of refraction in the experimentally observed region. These results suggest that architected nanolattices have the potential to serve as new optical components and devices across infrared frequencies.
光子晶体（PhC）色散特性的工程设计为PhC器件的设计和功能开启了新的范式。利用PhC的色散特性能够控制波在PhC内的传播。我们描述了用于中红外负折射的三维PhC光子带的设计、制造和实验观察。计算了能带结构和等频线以指导三维聚合物-锗核壳PhC的设计，该结构通过双光子光刻直接激光写入和溅射制造。我们成功地表征了聚合物-锗核壳晶格并绘制了其能带结构，然后用它来计算PhC的折射行为。对波传播的分析表明，这种三维核壳PhC对光进行负折射，并且在实验观察区域具有有效的负折射率。这些结果表明，构建的纳米晶格有潜力作为跨越红外频率的新型光学元件和器件。
