Comparison of Harmonic Generation from Crystalline and Amorphous Gallium Phosphide Nanofilms
Comparison of Harmonic Generation from Crystalline and Amorphous Gallium Phosphide Nanofilms
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DOI：
10.1002/adom.202300269
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发表时间：
2023-06
影响因子：
9
通讯作者：
Benjamin Tilmann;T. Huq;Thomas Possmayer;J. Dranczewski;B. Nickel;Haizhong Zhang;L. Krivitsky;A. Kuznetsov;L. de S. Menezes;S. Vezzoli;R. Sapienza;Stefan A. Maier
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文献类型：
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作者：
Benjamin Tilmann;T. Huq;Thomas Possmayer;J. Dranczewski;B. Nickel;Haizhong Zhang;L. Krivitsky;A. Kuznetsov;L. de S. Menezes;S. Vezzoli;R. Sapienza;Stefan A. Maier
磷化镓（GaP）是一种很有前途的纳米光子学材料，因为它具有很大的折射率和在大部分可见光谱上的透明度。然而，由于体相GaP不可能实现简单的相位匹配，因此仍然缺少对其谐波产生的非线性光学特性的全面研究，特别是当生长为薄膜时。在这里，二次谐波产生研究从外延生长的磷化镓薄膜，表明绝对转换效率是可比的散装晶圆在泵浦波长范围从1060到1370 nm。此外，将结果与非线性模拟进行比较，并提取了二阶非线性极化率，显示出与体材料相似的色散和幅度。此外，非晶GaP薄膜的三阶非线性极化率从三次谐波产生中提取，比晶体材料的三阶非线性极化率大一个数量级以上，并且报道了高达五次谐波的产生。结果表明，晶体和非晶薄膜的非线性光学与纳米天线和metasurfaces的潜力，特别是在可见光到近红外光谱的一部分。
Gallium phosphide (GaP) is a promising material for nanophotonics, given its large refractive index and a transparency over most of the visible spectrum. However, since easy phase‐matching is not possible with bulk GaP, a comprehensive study of its nonlinear optical properties for harmonic generation, especially when grown as thin films, is still missing. Here, second harmonic generation is studied from epitaxially grown GaP thin films, demonstrating that the absolute conversion efficiencies are comparable to a bulk wafer over the pump wavelength range from 1060 to 1370 nm. Furthermore, the results are compared to nonlinear simulations, and the second order nonlinear susceptibility is extracted, showing a similar dispersion and magnitude to that of the bulk material. Furthermore, the third order nonlinear susceptibility of amorphous GaP thin films is extracted from third harmonic generation to be more than one order of magnitude larger than that of the crystalline material, and generation of up to the fifth harmonic is reported. The results show the potential of crystalline and amorphous thin films for nonlinear optics with nanoantennas and metasurfaces, particularly in the visible to near infrared part of the spectrum.