Methods for adjusting beam properties for laser processing coated substrates

A method of laser processing a coated substrate, the method comprising:

• determining that a transmittance of a pulsed laser beam directed through a coated substrate is below a threshold, wherein the coated substrate comprises a coating layer disposed on a transparent workpiece;
• modifying the pulsed laser beam by directing the pulsed laser beam down at least one of a plurality of beam paths comprising:
• a polarization-adjusting beam path through which a polarization of the pulsed laser beam is adjusted;
• and
• a frequency-adjusting beam path through which a frequency of the pulsed laser beam is adjusted by at least one optical element configured to perform sum frequency generation on the pulsed laser beam;
• and
• forming a contour of defects in the transparent workpiece by directing the modified pulsed laser beam through the coating layer into the transparent workpiece and translating at least one of the transparent workpiece and the modified pulsed laser beam relative to each other along a contour line, wherein:
• the modified pulsed laser beam forms a laser beam focal line in the transparent workpiece, the laser beam focal line inducing absorption in the transparent workpiece, the induced absorption producing one of the defects of the contour of defects in the transparent workpiece;
• and
• the laser beam focal line formed from the modified pulsed laser beam comprises:
• a wavelength λ;
• a spot size wo;
• and
• a Rayleigh range ZR that is greater than
• F
• D
• ⁢
• π
• ⁢
• w
• o
• 2
• λ
• ,
• where FD is a dimensionless divergence factor.