title: Few-cycle pulse laser induced damage threshold determination of ultra-broadband optics.
abstract: A systematic study of few-cycle pulse laser induced damage threshold (LIDT) determination was performed for commercially-available ultra-broadband optics, (i.e. chirped mirrors, silver mirrors, beamsplitters, etc.) in vacuum and in air, for single and multi-pulse regime (S-on-1). Multi-pulse damage morphology at fluences below the single-pulse LIDT was studied in order to investigate the mechanisms leading to the onset of damage. Stark morphological contrast was observed between multi-pulse damage sites formed in air versus those in vacuum. One effect of vacuum testing compared to air included suppression of laser-induced periodic surface structures (LIPSS) formation, possibly influenced by a reduced presence of damage debris. Another effect of vacuum was occasional lowering of LIDT, which appears to be due to the stress-strain performance of the coating design during laser irradiation and under the external stress of vacuum ambience. A fused silica substrate is also examined, and a non-LIPSS nanostructuring is observed on the surface. Possible mechanisms are discussed.
authors.forename: Kyle R P
authors.initials: KR
authors.lastname: Kafka
authors.forename: Noah
authors.initials: N
authors.lastname: Talisa
authors.forename: Gabriel
authors.initials: G
authors.lastname: Tempea
authors.forename: Drake R
authors.initials: DR
authors.lastname: Austin
authors.forename: Catalin
authors.initials: C
authors.lastname: Neacsu
authors.forename: Enam A
authors.initials: EA
authors.lastname: Chowdhury