US 11,929,586 B2
Method of pulsed laser irradiation with reduced thermal damage
Masaaki Sakakura, Cambridge (GB); Yanhao Yu, Changchun (CN); Peter Kazansky, Southampton (GB); and Lei Wang, Changchun (CN)
Assigned to University of Southampton, Southampton (GB)
Filed by University of Southampton, Southampton (GB)
Filed on Feb. 22, 2021, as Appl. No. 17/181,414.
Claims priority of application No. 2002682 (GB), filed on Feb. 26, 2020.
Prior Publication US 2021/0265797 A1, Aug. 26, 2021
Int. Cl. H01S 3/00 (2006.01); B23K 26/0622 (2014.01)
CPC H01S 3/0057 (2013.01) [B23K 26/0624 (2015.10)] 22 Claims
OG exemplary drawing
 
1. A method of delivering optical energy to a substrate, comprising:
applying a temporal group of optical pulses to a region of the substrate, wherein the temporal group comprises twenty or fewer pulses of a femtosecond pulse duration, arranged as a first subgroup of pulses comprising up to three pulses followed by a second subgroup of pulses comprising the remaining pulses in the temporal group; and wherein
energies of the pulses are controlled such that pulses in the first subgroup have a first energy per pulse and pulses in a second subgroup of pulses have a second energy per pulse which is less than the first energy.