Gold nanocrystals (golden cubes) on surface of thin ferromagnetic (FM) heterostructures. Magnetization dynamics in FM is excited by microwaves (black half-circles) or by THz pulses (magenta arrow). Absorption of white light by gold nanocrystals and in turn excitation of surface plasmon resonance in AuNC affects magnetization dynamics in underlying FM layer. Spins with precession altered by AuNCs`light absorption are depicted with turquoise color, spins with unchanged precession with red.