Shi Xingzhe, Chen Changshui, Liu Songhao, Li Guangyuan
Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and Devices, School of Information Optoelectronic Science and Engineering, South China Normal University, Guangzhou 510006, China.
CAS Key Laboratory of Human-Machine Intelligence-Synergy Systems, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China.
Nanomaterials (Basel). 2020 Dec 16;10(12):2530. doi: 10.3390/nano10122530.
We propose a nonvolatile, reconfigurable, and narrowband mid-infrared bandpass filter based on surface lattice resonance in phase-change material Ge2Sb2Te5. The proposed filter is composed of a two-dimensional gold nanorod array embedded in a thick Ge2Sb2Te5 film. Results show that when Ge2Sb2Te5 transits from the amorphous state to the crystalline state, the narrowband reflection spectrum of the proposed filter is tuned from 3.197 μm to 4.795 μm, covering the majority of the mid-infrared regime, the peak reflectance decreases from 72.6% to 25.8%, and the corresponding quality factor decreases from 19.6 to 10.3. We show that the spectral tuning range can be adjusted by varying the incidence angle or the lattice period. By properly designing the gold nanorod sizes, we also show that the quality factor can be greatly increased to 70 at the cost of relatively smaller peak reflection efficiencies, and that the peak reflection efficiency can be further increased to 80% at the cost of relatively smaller quality factors. We expect that this work will advance the engineering of Ge2Sb2Te5-based nonvalatile tunable surface lattice resonances and will promote their applications especially in reconfigurable narrowband filters.
我们提出了一种基于相变材料Ge2Sb2Te5中的表面晶格共振的非易失性、可重构且窄带的中红外带通滤波器。所提出的滤波器由嵌入厚Ge2Sb2Te5薄膜中的二维金纳米棒阵列组成。结果表明，当Ge2Sb2Te5从非晶态转变为晶态时，所提出滤波器的窄带反射光谱从3.197μm调谐到4.795μm，覆盖了大部分中红外区域，峰值反射率从72.6%降至25.8%，相应的品质因数从19.6降至10.3。我们表明，可以通过改变入射角或晶格周期来调整光谱调谐范围。通过适当设计金纳米棒的尺寸，我们还表明，品质因数可以大幅提高到70，但代价是峰值反射效率相对较低，并且峰值反射效率可以进一步提高到80%，但代价是品质因数相对较小。我们期望这项工作将推动基于Ge2Sb2Te5的非易失性可调谐表面晶格共振的工程发展，并将促进它们的应用，特别是在可重构窄带滤波器中的应用。
