A laser system having - at least one excitation laser designed to generate laser pulses, - an amplifier designed to amplify laser light, and having - a high-frequency laser pulse source designed to generate a GHz laser pulse train with a single pulse repetition rate of single pulses in the GHz laser pulse train of at least 0.5 GHz, characterized in that - a beam switchover device (31,33) is arranged in front of the amplifier in the direction of light propagation, which device can be switched between a high-frequency functional position and a low-frequency functional position and is designed a) to supply at least one GHz laser pulse train of the high-frequency laser pulse source to the amplifier for amplification in the high-frequency functional position, and b) to supply at least one low-frequency laser pulse train with a single pulse repetition rate of individual laser pulses in the low-frequency laser pulse train of less than 0.5 GHz of the at least one excitation laser to the amplifier for amplification in the low-frequency functional position, - the beam switchover device (31,33) has at least one beam selector and at least one beam distributor, wherein laser pulses originating from the excitation laser are first split into different beam paths by the beam distributor and subsequently laser pulses originating from the different beam paths acting as different sources are selected by the beam selector depending on the functional position of the beam distributor and the beam selector and are guided to the amplifier. - at least one excitation laser designed to generate laser pulses, - an amplifier designed to amplify laser light, and having - a high-frequency laser pulse source designed to generate a GHz laser pulse train with a single pulse repetition rate of single pulses in the GHz laser pulse train of at least 0.5 GHz, characterized in that - a beam switchover device (31,33) is arranged in front of the amplifier in the direction of light propagation, which device can be switched between a high-frequency functional position and a low-frequency functional position and is designed a) to supply at least one GHz laser pulse train of the high-frequency laser pulse source to the amplifier for amplification in the high-frequency functional position, and b) to supply at least one low-frequency laser pulse train with a single pulse repetition rate of individual laser pulses in the low-frequency laser pulse train of less than 0.5 GHz of the at least one excitation laser to the amplifier for amplification in the low-frequency functional position, a) to supply at least one GHz laser pulse train of the high-frequency laser pulse source to the amplifier for amplification in the high-frequency functional position, and b) to supply at least one low-frequency laser pulse train with a single pulse repetition rate of individual laser pulses in the low-frequency laser pulse train of less than 0.5 GHz of the at least one excitation laser to the amplifier for amplification in the low-frequency functional position, - the beam switchover device (31,33) has at least one beam selector and at least one beam distributor, wherein laser pulses originating from the excitation laser are first split into different beam paths by the beam distributor and subsequently laser pulses originating from the different beam paths acting as different sources are selected by the beam selector depending on the functional position of the beam distributor and the beam selector and are guided to the amplifier.