Backscattered light properties during femtosecond laser ablation and development of a dynamic interferometric focusing system

Autor(es)

Raele, Marcus Paulo ; Samad, Ricardo Elgul ; Freitas, Anderson Zanardi ; De Pretto, Lucas ; Amaral, Marcello Magri ; Vieira, Nilson Dias, Jr. ; Wetter, Niklaus U. ; Kaierle, S ; Heinemann, SW

• Tipo de documento: Artigo Científico
• Fonte: HIGH-POWER LASER MATERIALS PROCESSING: APPLICATIONS, DIAGNOSTICS, AND SYSTEMS VII; v. 10525, p. 9-pg., 2018-01-01.

Resumo

The backscattered light originated when machining with femtosecond laser pulses can be used to accurately measure the processed surface position through an interferometer, as recently demonstrated by our group, in a setup that uses the same laser beam for ablation and inspection. The present work explores the characteristics of the laser light reflected by the target and its interaction with the resulting plasma to better understand its propagation physics and to improve the dynamic focusing system. The origin of this returning radiation was studied and has been traced, mainly, from the peripheral area of the focal spot (doughnut-like). By means of a Mach-Zehnder setup, the interferometric pattern was measured and analyzed aiming to access the influences of the plasma on the laser beam properties, and therefore on the retrieved information. Finally, the wavefront of the laser that creates and propagates through the plasma was characterized using a Shack-Hartmann sensor. (AU)

• Processo FAPESP: 13/26113-6 - Microusinagem com laser de pulsos ultracurtos aplicada na produção e controle de circuitos optofluídicos
• Beneficiário: Wagner de Rossi
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 15/24878-0 - Desenvolvimento de sistema interferométrico para controle dinâmico de foco aplicado na usinagem por laser de femtosegundos
• Beneficiário: Marcus Paulo Raele
• Modalidade de apoio: Auxílio à Pesquisa - Regular