Deep-Subwavelength Plasmon Polariton Atomic Cavity Detector for Frequency- and Polarization-Sensitive Terahertz Detection and Imaging

TL;DR

This paper introduces a graphene-based plasmonic cavity detector capable of deep-subwavelength, polarization-sensitive terahertz detection with high responsivity and fast response, suitable for imaging and semiconductor inspection.

Contribution

The work presents a novel graphene plasmon polariton atomic cavity detector that maintains high performance at deep-subwavelength scales, enabling compact, polarization-sensitive THz detection.

Findings

Achieves polarization-sensitive THz detection from 0.53 to 4.24 THz.

Demonstrates a responsivity of 1007 V/W and a response time of 230 ps.

Enables integration for polarization imaging and semiconductor inspection.

Abstract

Room-temperature, miniaturized, polarization-resolved terahertz (THz) detection of high speed is vital for high-resolution imaging in radar, remote sensing, and semiconductor inspection, and is essential for large-scale THz focal plane arrays. However, miniaturization below deep-subwavelength scales (< 1/50 wavelength) remain challenging due to weak light-matter interaction, which degrades responsivity and polarization sensitivity. Here, we present a graphene plasmon polariton atomic cavity (PPAC) monolithic detector that overcomes this limitation by maintaining and even enhancing performance at a deep-subwavelength channel length of just 2 micrometers (1/60 wavelength). The device integrates graphene rectangle PPAC arrays with dissimilar metal contacts, where graphene functions as both absorber and conductor, simplifying the architecture. Exploiting plasmon polariton resonances and the photothermoelectric (PTE) effect, the detector achieves polarization-sensitive, frequency-selective, and fast THz detection spanning 0.53 to 4.24 THz with a polarization ratio of 93, featuring a responsivity (RV) of 1007 V/W, a noise-equivalent power (NEP) of 16 pW/Hz^0.5, a specific detectivity (D*) of 2.9 x 10^7 Jones, and a response time of 230 ps. We further demonstrate monolithic integration for polarization imaging and non-destructive semiconductor chip inspection, advancing room-temperature, compact, and polarization-sensitive THz technologies.