Fractional Fresnel coefficients for optical absorption in femtosecond laser-induced rough metal surfaces

Muhammad Zubair, Yee Sin Ang, Kelvin J.A. Ooi, L. K. Ang

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

The surface morphology of metal influences its optical absorptivity. Recent experiments have demonstrated that the femtosecond laser induced surface structures on metals could be dynamically controlled by the fluence of laser and the number of pulses. In this paper, we formulate an analytical model to calculate the optical absorption of a rough metallic surface by modeling the roughness as a fractal slab. For a given experimental image of the surface roughness, we characterize the roughness with a fractal parameter by using the box-counting method. With this parameter as an input, we calculate the absorption of an 800 nm laser pulse impinging on gold, copper, and platinum, and the calculated results show excellent agreements. In terms of physics, our model can be viewed as a fractional version of the Fresnel coefficients, and it will be useful for designing suitable surface structures to tune the light absorption on metals from purely reflective to highly absorptive based on different applications.
Original languageEnglish (US)
JournalJOURNAL OF APPLIED PHYSICS
Volume124
Issue number16
DOIs
StatePublished - Oct 28 2018
Externally publishedYes

Bibliographical note

Generated from Scopus record by KAUST IRTS on 2023-09-20

ASJC Scopus subject areas

  • General Physics and Astronomy

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