US 12,463,395 B2
Laser system and method for the spectral broadening of pulsed laser radiation
Thomas Metzger, Munich (DE); and Sebastian Stark, Munich (DE)
Assigned to TRUMPF SCIENTIFIC LASERS GMBH + CO. KG, Unterfoehring (DE)
Filed by TRUMPF Scientific Lasers GmbH + Co. KG, Unterfoehring (DE)
Filed on Aug. 19, 2022, as Appl. No. 17/891,157.
Application 17/891,157 is a continuation of application No. PCT/EP2021/054860, filed on Feb. 26, 2021.
Claims priority of application No. 10 2020 105 015.1 (DE), filed on Feb. 26, 2020.
Prior Publication US 2022/0416493 A1, Dec. 29, 2022
Int. Cl. H01S 3/00 (2006.01); G02F 1/35 (2006.01); H01S 3/036 (2006.01); H01S 3/08 (2023.01); H01S 3/094 (2006.01); H01S 3/10 (2006.01); H01S 3/22 (2006.01)
CPC H01S 3/0057 (2013.01) [G02F 1/3503 (2021.01); H01S 3/005 (2013.01); H01S 3/036 (2013.01); H01S 3/08095 (2013.01); H01S 3/094076 (2013.01); H01S 3/10038 (2013.01); H01S 3/10061 (2013.01); H01S 3/2207 (2013.01); G02F 1/3511 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A laser system comprising:
a laser radiation source for providing pulsed laser radiation, wherein the pulsed laser radiation comprises laser pulses having pulse energies in a range of 1 mJ to 100 J and pulse durations in a range of 10 fs to 5 ps, and
an optical system for spectral broadening of the pulsed laser radiation, the optical system comprising:
a first polarization setting optical unit, configured to change a linear polarization state into a circular polarization state of the pulsed laser radiation,
a multipass cell having at least two mirrors, wherein the pulsed laser radiation passes through the multipass cell with formation of a plurality of intermediate focus zones, wherein the multipass cell is filled with a filling gas that has an optical nonlinearity and causes a spectral broadening of the pulsed laser radiation in the intermediate focus zones, and
a second polarization setting optical unit for returning the circular polarization state to the linear polarization state, wherein the second polarization setting optical unit is disposed downstream of the multipass cell,
wherein a pressure of the filling gas is set in a pressure range so that there is an ionization behavior of the filling gas in a form of multiphoton ionization, and focus diameters of the intermediate focus zones are set such that a peak intensity of the pulsed laser radiation passing through the multipass cell is below an ionization threshold value of the filling gas, wherein the ionization threshold value of the filling gas is increased for circular polarized radiation as compared to linear polarized radiation.