Abstract: A method and arrangement for producing ultrashort light pulses of tunable wavelength and pulse duration for use in spectroscopy, photobiology and in the medical science comprises a pumping radiation source for producing a substantially coherent radiation. A grating is provided for producing a first and a second partial beam from the coherent radiation which are superimposed in a laser active medium operating to the distributed feedback principle, for generating a laser beam in a first range of the laser active medium. According to the invention a third partial beam is produced at said grating. The third partial beam is fed into the laser active medium into a second range of the same which is either entirely or partially or not at all overlapping said first range. The second range is passed by the laser beam. A tiltable planoparallel plate is inserted into the coherent radiation for displacing the first and second partial beam relative to the third partial beam and, hence, the first and second range.