Plasmonic interferometry is a rapidly growing area of research with a huge potential for applications in the terahertz frequency range. In this Letter, we explore a plasmonic interferometer based on graphene field effect transistor connected to specially designed antennas. As a key result, we observe helicity- and phase-sensitive conversion of circularly polarized radiation into dc photovoltage caused by the plasmon-interference mechanism: two plasma waves, excited at the source and drain part of the transistor, interfere inside the channel. The helicity-sensitive phase shift between these waves is achieved by using an asymmetric antenna configuration. The dc signal changes sign with inversion of the helicity. A suggested plasmonic interferometer is capable of measuring the phase difference between two arbitrary phase-shifted optical signals. The observed effect opens a wide avenue for phase-sensitive probing of plasma wave excitations in two-dimensional materials.

中文翻译：

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螺旋敏感性等离子太赫兹干涉仪。

等离子体干涉测量法是一个快速发展的研究领域，具有在太赫兹频率范围内应用的巨大潜力。在这封信中，我们探索了一种基于石墨烯场效应晶体管的等离子干涉仪，该晶体管连接到专门设计的天线上。作为一个关键的结果，我们观察到由等离子体激元干扰机制引起的圆偏振辐射的螺旋度和相位敏感转换为直流光电压：在晶体管的源极和漏极部分激发的两个等离子体波在通道内部发生干扰。通过使用非对称天线配置，可以实现这些波之间对螺旋度敏感的相移。直流信号随着螺旋度的反转而改变符号。建议的等离子体干涉仪能够测量两个任意相移光信号之间的相位差。