Coherent manipulation and excitation of surface plasmon polaritons by heat loss and gain at the interface of graphene-dielectric medium

A four-level atomic configuration with heat gain and loss mechanisms is used to study the manipulation and excitation of surface plasmon polaritons (SPPs) at the interface of graphene and the dielectric configuration. The study analyzes the dispersion relation, wavelength, propagation length, penetration depth, and phase shift of SPPs under different heat conditions and medium parameters. The study shows that heat gain and loss shift the dielectric medium’s absorption and dispersion resonances, while in graphene the strength of absorption and dispersion is controlled by probe and control detunings. Resonance angles shift slightly negatively under heat loss ( 𝑄 < 0 ) and positively under heat gain ( 𝑄 > 0 ), maintaining SPP excitation in the transmission and reflection spectra. Heat gain and heat loss both increase the imaginary part of the SPP wavevector relative to the no-heat case, with heat gain producing the strongest attenuation and the shortest propagation length. The penetration depths of the SPP field in graphene and the dielectric medium exhibit pronounced resonance-dependent variations, while heat gain and heat loss shift these spatial profiles, providing thermal control over SPP confinement. Near resonance, the SPP phase response varies rapidly, with heat loss producing a sharper phase variation and heat gain producing a broader response. These results pave the way for the development of temperature-controlled nanophotonic devices, optical switches, and plasmonic sensors.