We present a detailed study of the photoinduced magnetization precession and magnetic relaxation in epitaxial Pd/Fe films on MgO(0 0 1) substrates via all-optical pump-probe techniques. We explicitly formulate the correlation between the Gilbert damping and the effective damping in the optical approach. Furthermore, a non-local Gilbert damping induced by spin pumping is demonstrated self-consistently by the Gilbert damping dependence on Pd thickness and the 1/d Fe relationship of damping with Fe thickness d Fe . The non-local Gilbert damping enables the determination of spin diffusion length λ SD = (7.4 ± 3.0) nm in Pd and interfacial spin mixing conductance g ↑↓ = (2.7 ± 0.4) × 10 19 m −2 . Our work paves the way toward the optical determination of spin transport parameters.

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