The paper discusses the properties of plasmons in doped graphene at infra-red frequencies, highlighting their potential for low-loss and significant wave localization. Plasmons in graphene can achieve low losses and high wave localization for frequencies below the optical phonon frequency ($\omega_{Oph} \approx 0.2$ eV). Interband losses, which occur via the excitation of electron-hole pairs, can be reduced by increasing doping levels, pushing the interband threshold frequency towards higher frequencies. For sufficiently large dopings, there is a bandwidth of frequencies from $\omega_{Oph}$ to the interband threshold where plasmon decay via the emission of an optical phonon and an electron-hole pair becomes significant. The calculations are performed using the random-phase approximation and number-conserving relaxation-time approximation, with the DC relaxation time serving as an input parameter. The optical properties of plasmons in graphene are similar to those of surface plasmons on dielectric-metal interfaces, making graphene plasmons potentially useful for nanophotonic applications. The study also explores the relaxation times due to electron-phonon coupling, showing that optical phonons are an important decay mechanism for frequencies above $\omega_{Oph}$. Overall, the results suggest that graphene plasmons could offer advantages over conventional surface plasmons in terms of wave localization and propagation lengths, making them promising for nano-photonics and metamaterials applications.The paper discusses the properties of plasmons in doped graphene at infra-red frequencies, highlighting their potential for low-loss and significant wave localization. Plasmons in graphene can achieve low losses and high wave localization for frequencies below the optical phonon frequency ($\omega_{Oph} \approx 0.2$ eV). Interband losses, which occur via the excitation of electron-hole pairs, can be reduced by increasing doping levels, pushing the interband threshold frequency towards higher frequencies. For sufficiently large dopings, there is a bandwidth of frequencies from $\omega_{Oph}$ to the interband threshold where plasmon decay via the emission of an optical phonon and an electron-hole pair becomes significant. The calculations are performed using the random-phase approximation and number-conserving relaxation-time approximation, with the DC relaxation time serving as an input parameter. The optical properties of plasmons in graphene are similar to those of surface plasmons on dielectric-metal interfaces, making graphene plasmons potentially useful for nanophotonic applications. The study also explores the relaxation times due to electron-phonon coupling, showing that optical phonons are an important decay mechanism for frequencies above $\omega_{Oph}$. Overall, the results suggest that graphene plasmons could offer advantages over conventional surface plasmons in terms of wave localization and propagation lengths, making them promising for nano-photonics and metamaterials applications.