Fig. 1. Fundamental of surface plasmons^[29]. (a) Schematic of surface plasmon polaritons at metal-dielectric interface; (b) schematic of localized surface plasmon resonance in metal nanosphere

Fig. 2. Schematic of the graphene photo-detector experiment. (a) Structure schematic of the graphene photo-detector^[37]; (b) photocurrents at different polarization angles; (c) schematic diagram of the graphene plasmon device for gas identification^[38]

Fig. 3. Detector schematic. (a) Experimental setup for optical data reception^[39]; (b) schematic of a plasma enhanced graphene detector^[39]; (c) schematic of the proposed graphene plasmonic potodetector ^[40]; (d) photocurrents depending on the light excitation on and off^[40]; (e) top- and side-view illustration of a typical graphene micro-ribbon array^[41]; (f) variation of the absorption peak of graphene plasmon with gate pressure^[41]; (g) change of the absorption peak of graphene plasmon with different graphene micro-ribbon widths^[41]

Fig. 4. Schematic of the graphene photo-detector experiment. (a) Schematic of the device architecture of the plasmon-assisted hot carrier generation on an asymmetrically nanopatterned graphene ^[42]; (b) a scanning electron microscope image of the partly patterned graphene^[42]; (c) simulated temperature and potential of a graphene photodetector^[42]; (d) schematic of the sensor^[43]; (e) a scanning electron microscope image of the graphene nanoribbon pattern^[43]; (f) transfer curve of our graphene/CaF₂ fingerprint sensor^[43]; (g) schematic illustration of the acoustic plasmon resonator architecture and coupling routes to plasmon modes for a incident plane wave with TM polarization ^[44]

Fig. 5. Schematic diagrams of graphene-based detector. (a) Schematic diagram of the graphene-based detector with plasmonic nanoparticles^[45]; (b) a plasmonic excitation map of nanostructure-free and nanostructure^[45]; (c) schematic illustration of the step-wise process for fabrication of the near infrared photodetector^[46]; (d) photoresponse of three representative devices under 850 nm light illumination at biasvoltageVbias=0V^[46]; (e) schematic diagram of the graphene-based photodetector ^[47]; (f) responsivity of monolayer graphene with and without Au nanoparticles versus excitation wavelength varying from 550 nm to 850 nm^[47]

Fig. 6. Schematic diagram of quantum dot detector. (a) Structure schematic of the hybrid phototransistor based on Si QDs and graphene^[48]; (b) two distinct optical optical phenomena of Si QDs exploited during the phototransistor operation^[48]; (c) schematic of quantum dot photodetector based on plasma^[50]

Fig. 7. Schematic diagram of detector based on periodic nanostructure. (a) Schematic diagram of proposed LWIR photodetector with hybrid plasmonic structure^[55]; (b) zoomed view of the aperture nanobar antennas^[55]; (c) depiction of the interference mechanism^[56]; (d) schematic map of the photodetector^[56]; (e) scanning electron microscope image^[56]; (f) schematic diagram of the Schottky photodetector composed of Si substrate/Au nanograting^[57]; (g) graphene nanoribbon arrays with different filling factors, in which the ribbon widths are 140 nm^[58]; (h) schematic of graphene nanodisk plasmon arrays^[58]