Thermo-optical Effect in Phase-Change Nanophotonics
Thermo-optical Effect in Phase-Change Nanophotonics
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DOI：
10.1021/acsphotonics.6b00032
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发表时间：
2016-05-01
期刊：
影响因子：
7
通讯作者：
Pernice, Wolfram H. P.
中科院分区：
文献类型：
--
作者：
Stegmaier, Matthias;Rios, Carlos;Pernice, Wolfram H. P.
与纳米光子器件集成的相变材料(PCM)可以实现可调谐的集成光学器件，并通过利用在非晶态和晶态之间切换时的光学特性的巨大对比度，在长期光子数据存储方面具有潜在的应用前景。相变依赖于短的热脉冲，这可以通过光学手段方便地提供。因此，正确理解温度引起的折射率波动，即热光效应，对于控制和优化器件运行是至关重要的。在这里，我们分析了集成在纳米光子波导上的Ge2Sb2Te5纳米结在通信波长下的热光效应。我们提取了晶态和非晶态的实部和虚部的热光系数。我们观察到热光系数在相变时的符号反转，我们追溯到在所研究的光谱范围内两个相态的不同色散。我们的发现将允许设计基于PCM的调制器、非易失性存储系统和可重新配置的光子器件。
Phase-change materials (PCMs) integrated with nanophotonic components enable tunable integrated optical devices and hold promise for emerging applications in long-term photonic data storage by exploiting the large contrast in optical properties when switched between amorphous and crystalline phase states. The phase transitions rely on short heat pulses, which can be conveniently supplied by optical means. Therefore, a proper understanding of the temperature-induced refractive index fluctuations, the thermo-optical effect, is essential for controlled and optimized device operation. Here we analyze the thermooptical effect of Ge2Sb2Te5 nanojunctions integrated atop nanophotonic waveguides at telecommunication wavelengths. We extract the thermo-optical coefficients for the crystalline and amorphous phase state, both the real and imaginary part. We observe sign reversal of the thermo-optical coefficient upon phase change, which we trace back to different chromatic dispersion of the two phase states within the studied spectral regime. Our findings will allow for designing PCM-based modulators, nonvolatile memory systems, and reconfigurable photonic devices.