This paper demonstrates that 100% light absorption can be achieved in a single patterned sheet of doped graphene. The key idea is that a planar array of small lossy particles can exhibit full absorption under critical-coupling conditions when the cross-section of each particle is comparable to the area of the lattice unit-cell. Specifically, arrays of doped graphene nanodisks can achieve full absorption when supported on a substrate under total internal reflection or lying on a dielectric layer coating a metal. This has potential applications in infrared light detectors and sources, which can be made tunable via electrostatic doping of graphene. The paper discusses the optical response of graphene nanodisks, showing that doped graphene can support strongly confined, long-lived plasmons, which produce sharp infrared resonances in nanodisks much smaller than the light wavelength. The extinction cross-section of graphene disks can exceed their geometrical area by over an order of magnitude. This is due to the fact that the maximum extinction cross-section can be much larger than the geometrical area, even though the disks are not perfect two-level systems. The paper also discusses the universal limit to absorption by a thin layer. In a symmetric environment, the maximum absorption is limited to 50%, but this can be increased by considering asymmetric environments. The paper shows that the maximum possible absorption produced by a thin, periodically structured material layer is determined by the properties of the interface between two media. The paper also discusses the robustness of total light absorption under total internal reflection. It shows that the peak absorbance is represented as a function of incidence angle for various values of the lattice spacing, and nearly total light absorption is observed within a certain range of incidence angles under critical coupling conditions. Finally, the paper discusses omnidirectional total light absorption. It shows that the above prediction of total light absorption under total internal reflection can be generalized to systems in which the transmission channel is suppressed. The paper also discusses the possibility of omnidirectional absorption, which is achieved when the second term in the resonant frequency dominates. This condition is fulfilled by many non-ideal two-level atoms/molecules, such as NV centers. The paper concludes that planar textured materials can produce large light absorption, which reaches 100% when the transmission channel is suppressed.This paper demonstrates that 100% light absorption can be achieved in a single patterned sheet of doped graphene. The key idea is that a planar array of small lossy particles can exhibit full absorption under critical-coupling conditions when the cross-section of each particle is comparable to the area of the lattice unit-cell. Specifically, arrays of doped graphene nanodisks can achieve full absorption when supported on a substrate under total internal reflection or lying on a dielectric layer coating a metal. This has potential applications in infrared light detectors and sources, which can be made tunable via electrostatic doping of graphene. The paper discusses the optical response of graphene nanodisks, showing that doped graphene can support strongly confined, long-lived plasmons, which produce sharp infrared resonances in nanodisks much smaller than the light wavelength. The extinction cross-section of graphene disks can exceed their geometrical area by over an order of magnitude. This is due to the fact that the maximum extinction cross-section can be much larger than the geometrical area, even though the disks are not perfect two-level systems. The paper also discusses the universal limit to absorption by a thin layer. In a symmetric environment, the maximum absorption is limited to 50%, but this can be increased by considering asymmetric environments. The paper shows that the maximum possible absorption produced by a thin, periodically structured material layer is determined by the properties of the interface between two media. The paper also discusses the robustness of total light absorption under total internal reflection. It shows that the peak absorbance is represented as a function of incidence angle for various values of the lattice spacing, and nearly total light absorption is observed within a certain range of incidence angles under critical coupling conditions. Finally, the paper discusses omnidirectional total light absorption. It shows that the above prediction of total light absorption under total internal reflection can be generalized to systems in which the transmission channel is suppressed. The paper also discusses the possibility of omnidirectional absorption, which is achieved when the second term in the resonant frequency dominates. This condition is fulfilled by many non-ideal two-level atoms/molecules, such as NV centers. The paper concludes that planar textured materials can produce large light absorption, which reaches 100% when the transmission channel is suppressed.