Аннотация:We present an experimental investigation of photooxidation of a diamond surface exposed to femtosecond laser pulses that induce transient high concentrations of free carriers (>10(22)cm(-3)) while the lattice stays cold. Etching rate measurements and a laser-induced plasma study indicated that the rate of desorption of carbon species is proportional to the square of the induced plasma density, which contrasts with previous investigations of diamond etching by nanosecond pulses. We discuss how laser-induced ionization of diamond occurs and how it affects the photoreaction mechanism.