Influence of edge effects on laser-induced surface displacement of opaque materials by photothermal interferometry

Flizikowski, Gabriel Antonio Siqueira (author), Anghinoni, Bruno (author), Rohling, J. H. (author), Belançon, M. P. (author), Mendes, R. S. (author), Baesso, Mauro L. (author), Malacarne, L. C. (author), Požar, Tomaž (author), Bialkowski, Stephen Edward (author), Astrath, Nelson Guilherme Castelli (author)

We demonstrate the influence of edge effects on the photothermal-induced phase shift measured by a homodyne quadrature laser interferometer and compare the experiments with rigorous theoretical descriptions of thermoelastic surface displacement of metals. The finite geometry of the samples is crucial in determining how the temperature is distributed across the material and how this affects the interferometer phase shift measurements. The optical path change due to the surface thermoelastic deformation and thermal lens in the surrounding air is decoded from the interferometric signal using analytical and numerical tools. The boundary/edge effects are found to be relevant to properly describe the interferometric signals. The tools developed in this study provide a framework for the study of finite size effects in heat transport in opaque materials and are applicable to describe not only the phase shift sensed by the interferometer but also to contribute to the photothermal-based technologies employing similar detection mechanisms.

• Language: English
• Keywords: photothermal mirror, interferometry, thermal expansion
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering
• Publication status: Published
• Publication version: Author Accepted Manuscript
• Year: 2020
• Number of pages: Str. 1-10
• Numbering: Vol. 128, iss. 4
• PID: 20.500.12556/RUL-117988
• UDC: 519.6:531.715(045)
• ISSN on article: 0021-8979
• DOI: 10.1063/5.0015996
• COBISS.SI-ID: 24363523
• Publication date in RUL: 04.08.2020

Record is a part of a journal

• Title: Journal of applied physics
• Shortened title: J. appl. phys.
• Publisher: American Institute of Physics.
• ISSN: 0021-8979
• COBISS.SI-ID: 4730378

Secondary language

• Language: Slovenian
• Title: Vpliv robnih učinkov na lasersko induciran pomik površine neprozornih materialov s fototermalno interferometrijo

Abstract

Prikažemo vpliv robnih učinkov na fototermalno inducirani fazni premik, ki ga merimo s homodinskim kvadraturnim laserskim interferometrom in poskuse primerjamo z eksaktnimi teoretičnimi opisi termoelastičnih površinskih premikov kovin. Končna geometrija vzorcev je ključnega pomena pri določanju, kako se temperatura porazdeli po materialu in kako to vpliva na merjenje faznega premika interferometra. Razliko optične poti zaradi površinske termoelastične deformacije in termalne leče v okoliškem zraku dekodiramo iz interferometričnega signala s pomočjo analitičnih in numeričnih orodij. Mejni/robni učinki so pomembni za pravilen opis interferometričnih signalov. Orodja, razvita v tej študiji, nudijo okvir za preučevanje učinkov zaradi končnih dimenzij pri prenosu toplote v neprozornih materialih in niso uporabna le za opisovanje faznega premika, ki ga zazna interferometer, temveč prispevajo tudi k fototermalnim tehnologijam, ki uporabljajo podobne mehanizme zaznavanja.

• Keywords: fototermalno zrcalo, interferometrija, termoelastična ekspanzija

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P2-0392
• Name: Optodinamika

• Funder: ARRS - Slovenian Research Agency
• Project number: L2-9254
• Name: Prostorsko in časovno oblikovanje laserske svetlobe za minimalno invazivne oftalmološke posege