A method is disclosed for applying laser energy having desired pulse characteristics, including a sufficiently short duration and/or a sufficiently high energy for the photomechanical treatment of skin tattoos. The laser energy may be generated with an apparatus having a resonator with the capability of switching between a modelocked pulse operating mode and an amplification operating mode. The operating modes are carried out through the application of a time-dependent bias voltage, having waveforms as described herein, to an electro-optical device - e.g., a Pockels cell 20 - positioned along the optical axis of the resonator formed by two mirrors 12, 14 comprising a lasing medium 16 and a polarizer 18 to dump the beam out of the cavity.