  Plasmon excitations in metallic nanostructures can decay directly into
dynamic electron-hole pairs (EHPs), exploitable for photocurrent generation.
This approach has extensively been employed to develop nanoplasmonic
light-sensing devices with significant responsivity and quantum efficiency. Of
particular interest is infrared plasmonic photodetectors with a wide range of
technological applications, including spectroscopy, biosensing, and
surveillance. This Review discusses fundamentals, recent advances, and trending
mechanisms in the understanding and applications of plasmon-enhanced
photocurrent generation in nanostructures across the infrared spectrum. By
highlighting and comparing the developed techniques, we demonstrate the newly
introduced directions toward achieving high-photon yield infrared plasmonic
photodetection tools. As a promising concept in modern photonics, we represent
the emergence of toroidal meta-atoms as plasmon-induced carrier generators with
unconventionally exquisite properties for designing advanced, rapid, and
next-generation plasmonic photodetectors with significantly high responsivity
and photocurrent.
