Field-Effect Plasmonic Transistors Based on Metallic–Semiconducting Carbon Nanotube Junctions

Nanophotonic circuits are regarded as a transformative technology that can overcome many challenges faced by electronic circuits, particularly concerning operating frequency limits. However, the development of nanophotonic circuits utilizing plasmons is strongly hampered by the absence of fundamental building blocks such as long-lived deep-subwavelength plasmons, plasmonic waveguides, and field-effect plasmonic transistors (FEPTs). Here, we demonstrate Luttinger-liquid FEPTs based on metallic-semiconducting carbon nanotube junctions. In these devices, the propagation of plasmon waves across the junction can be efficiently controlled by electrostatic gating. Theoretical analysis and numerical simulations indicate that the reflection/transmission of Luttinger-liquid plasmons at junctions can be captured well by the Fresnel equation. This result suggests that the classical Fresnel law persists for Luttinger-liquid plasmons with a reduced dimensionality. Our study not only uncovers the fundamental propagation characteristics of Luttinger-liquid plasmons at junctions but also introduces a new category of FEPTs that could facilitate the development of high-frequency nanophotonic circuits.