A laser source apparatus is for providing a beam path to generate a first laser beam and a second laser beam. The laser source apparatus includes a laser generator, at least one spectrum broadening unit and a beam splitter on the beam path. The laser generator is configured to generate an original laser beam with a pulse duration smaller than 1 ps. The spectrum broadening unit is configured in a following stage of the laser generator. The spectrum broadening unit includes a multiple plate continuum. The multiple plate continuum includes a plurality of thin plates, and the thin plates are configured along the beam path in order. The beam splitter is configured in the following stage of the laser generator to divide the original laser beam into the first laser beam and the second laser beam.