The invention relates to a passively mode-coupled femtosecond laser whose ring resonator comprises the following elements: a) a laser-active element (1); b) at least one dielectric mirror (2), which has a negative group velocity dispersion (GGD) such that, for a coherent portion of the optical spectral region that is capable of being amplified by the laser-active element (1), the sum of the group velocity dispersions of the mirror (2) and of the positive group velocity dispersion of the laser-active element (1) is negative (see formula (a)); c) two concave mirrors (21) and (22) which are adjacently arranged next to the laser-active element (1) in a spatial manner and which are oriented with the concave surfaces thereof toward the same, and; d) an optical decoupler (3). The optical path length in the resonator is less than 60 cm, preferably less than 30 cm, especially less than 15 cm. The focal distances f21 and f22 of the concave mirrors (21) and (22) are less than 3 cm, preferably less than 2 cm, especially less than or equal to 1.5 cm such that it is possible to attain a highly repetitive generation of femtosecond pulses. The invention additionally relates to a continuously variable highly-repetitive femtosecond laser, to the use of the same for carrying out the highly-repetitive generation of femtosecond pulses and to a method for tuning the same.
展开▼
