Optical-field emission from nanostructured solids such as subwavelength nanoantennas can be leveraged to create sub-femtosecond, petahertz-scale electronics for optical-field detection. One application of particular interest is the detection of an incident optical pulse’s carrier–envelope phase (CEP). Such CEP detection requires few-cycle, broadband optical excitation where the resonant properties of the nanoantenna can strongly alter the response of the near field in time. Little quantitative investigation has been performed to understand how the geometry and resonant properties of the antennas should be tuned to enhance the CEP sensitivity and signal-to-noise ratio. Here we examine how the geometry and resonance frequency of planar plasmonic nanoantennas can be engineered to enhance the emitted CEP-sensitive photocurrent when driven by a few-cycle optical pulse. We find that with the simple addition of curved sidewalls leading to the apex, and proper tuning of the resonance wavelength, the net CEP-sensitive current per nanoantenna can be improved by $5 \!-\! 10 \times$, and the signal-to-noise-ratio by $50\! -\! 100 \times$ relative to simple triangular antennas operated on resonance. Our findings will inform the next generation of nanoantenna designs for emerging applications in ultrafast photoelectron metrology and petahertz electronics.

中文翻译：

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用于增强载波-包络相位灵敏度的纳米天线设计

可以利用来自纳米结构固体（例如亚波长纳米天线）的光场发射来创建用于光场检测的亚飞秒、太赫兹级电子设备。一个特别令人感兴趣的应用是检测入射光脉冲的载波包络相位 (CEP)。这种 CEP 检测需要少周期的宽带光激发，其中纳米天线的谐振特性可以及时强烈地改变近场的响应。很少进行定量研究来了解应如何调整天线的几何形状和谐振特性以提高 CEP 灵敏度和信噪比。在这里，我们研究了如何设计平面等离子体纳米天线的几何形状和共振频率，以在由几个周期的光脉冲驱动时增强发射的 CEP 敏感光电流。我们发现，通过简单地添加通向顶点的弯曲侧壁，并适当调整谐振波长，可以通过以下方式改善每个纳米天线的净 CEP 敏感电流$5 \!-\! 10 \times$，信噪比为$50\！-\! 100 \times$相对于谐振操作的简单三角形天线。我们的发现将为下一代纳米天线设计提供信息，用于超快光电子计量学和太赫兹电子学中的新兴应用。