A multifunctional laser device configured to be applicable as such in each of: multiple photon processes, nano structuring processes, optical coherence tomography, Terahertz (THZ) spectroscopy, THz imaging; or a combination of such processes; and comprising a mode-locked linear (X or Z-folded) fs laser resonator having a repetition rate of at least 300 MHz and 600 MHz at most and, thus, a corresponding short resonator length, said fs laser resonator further being a dispersive mirrors cavity having an average negative GDD (Group Delay Dispersion) in the spectral range of the laser operation, and being arranged to generate laser pulses with a pulse width of less than 30fs, and comprising a pump laser operating at an optical output pump power of less than 2W.