This invention provides a solution for operating a mode-locking and cavity dumping laser apparatus using a single electro-optical switch or modulator, such as a Pockels cell, without the need of multiplexing between two sources of voltage. The complex waveform of electrical signal, which controls the Pockels Cell is achieved by employing the phenomena, called LC circuit ringing, where the LC circuit is formed from an inductive element and a capacitor, where the Pockels Cell works as a capacitor itself. The ringing frequency should be calculated such that the period of oscillations is preferably two times longer than the round-trip time of a light pulse inside the optical cavity. As a result, optical losses are created inside the cavity with a period, which coincides with the travel of a light pulse, thus the pulse build-up is consistent and stable.