A laser system for generating at least one pulse and/or pulse sequence(s) of pulses having at least one specified property, such as pulse energy, duration, peak intensity, pulse form and/or timing includes an amplifying cavity. The amplification process is monitored in the amplifying cavity to obtain data about at least one property of the pulse sequence and/or the single pulse(s). The system also compares the obtained data with reference data and it controls at least one switching means for inputting, outputting and/or retaining the pulse(s) in the amplifying cavity such that at least one property of the pulse sequences and/or the pulses at an output of the laser system has substantially a specified value.