{
  "abstract": "Laser-induced surface microstructuring has emerged as a powerful strategy for tailoring optical properties of metals for applications in energy systems, sensing, and stealth technologies. The present study provides a systematic investigation of femtosecond laser-induced Grey and Black surface states on AISI 321 stainless steel and its covering layers, revealing a previously unresolved transition between oxidation-dominated and topography-enhanced light absorption regimes, and quantitatively decoupling their respective contributions. The applied femtosecond laser irradiation produces two distinct classes of low-reflectivity surface microstructures with markedly different morphologies and optical responses. At lower laser intensities, a Grey surface forms via a Two-Scale Laser-Induced Periodic Surface Structures (TS-LIPSS), where high-frequency classical Laser-Induced Periodic Surface Structures (LIPSS) coexist with incipient microcraters. At higher intensities, a Black surface develops, characterized by a Quasi-Periodic Laser-Induced Deep Surface Structures (QP-LIDSS) composed of densely distributed deep craters. Correlated structural, chemical, and optical analyses reveal different dominant mechanisms of reflectivity reduction. The Grey surface is primarily governed by thin oxide layers (∼20 nm) superimposed on nanoscale texturing, whereas the Black surface combines thicker oxides (∼50 nm) with pronounced crater-assisted light trapping. UV–Vis–NIR spectroscopy shows a stepwise reflectivity decrease from 47% (untreated) to 34% (Grey) and 14–16% (Black), supported by grazing-incidence scattering and COMSOL-based modelling. Quantitative analysis of roughness parameters demonstrates that no single descriptor is sufficient to capture the optical behavior. Instead, reflectivity correlates with combined parameter groups - core, amplitude, spatial development, and with the interfacial area ratio emerging as the most sensitive indicator when coupled with spectral and scale-dependent analysis. These results establish a transition from oxidation-driven light suppression to coupled oxidation–topography-controlled effect, offering a scalable route to engineer stainless-steel surfaces via femtosecond laser treatment. The ability to tune the optical response via laser processing offers a scalable route to creating functional surfaces with enhanced optical and electromagnetic performance. Unlike typical studies focusing solely on the final high-roughness dual-scale morphology, this work demonstrates how the transition from oxidation-driven light suppression on sub-wavelength ripples (TS-LIPSS) to geometric trapping on dual-scale structures (QP-LIDSS) can be utilized to precisely tune the optical state of industrial alloys without complex chemical treatment.",
  "abstract_shown": true,
  "affiliations": [
    "”NoviNano Lab” LLC., 5 Pasternaka Str., 79015, Lviv, Ukraine; Department of Applied Physics and Nanomaterials Science, Lviv Polytechnic National University, 12 S. Bandery str., 79013, Lviv, Ukraine; Corresponding author.",
    "NanoBioMedical Centre, Adam Mickiewicz University, Wszechnicy Piastowskiej 3, 61-614, Poznań, Poland; Institute for Single Crystals, NAS of Ukraine, 60, Nauky ave., 61-072, Kharkiv, Ukraine",
    "National Technical University ''Kharkiv Polytechnic Institute'', 2, Kyrpychova str, 61-002, Kharkiv, Ukraine",
    "NanoBioMedical Centre, Adam Mickiewicz University, Wszechnicy Piastowskiej 3, 61-614, Poznań, Poland",
    "Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, Hamburg, 22607, Germany",
    "Faculty of Mechanical Engineering, Poznań University of Technology, Piotrowo 3, 61-138, Poznań, Poland",
    "Center of Advanced Technologies, Adam Mickiewicz University, Uniwersytetu Poznańskiego 2, 61-614, Poznań, Poland; Faculty of Materials Science and Technical Physics, Poznań University of Technology, Piotrowo 3, 61-138, Poznań, Poland",
    "Faculty of Physics and Astronomy, Adam Mickiewicz University, Uniwersytetu Poznańskiego 2, 61-614, Poznań, Poland; Department of Physics and Biophysics, Faculty of Food Science and Nutrition, Poznań University of Life Sciences, Wojska Polskiego 38/42, 60-637, Poznań, Poland",
    "Electron Microscopy Centre, University of Wollongong, Innovation Campus, North Wollongong, 2500, Australia",
    "National Technical University ''Kharkiv Polytechnic Institute'', 2, Kyrpychova str, 61-002, Kharkiv, Ukraine; Department of Physics and Biophysics, Faculty of Food Science and Nutrition, Poznań University of Life Sciences, Wojska Polskiego 38/42, 60-637, Poznań, Poland"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 13,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Iaroslav M. Gnilitskyi"
    },
    {
      "affs": [
        1
      ],
      "name": "Mariya Dobrotvorska"
    },
    {
      "affs": [
        2
      ],
      "name": "Borys A. Aleksenko"
    },
    {
      "affs": [
        3
      ],
      "name": "Mikołaj Lewandowski"
    },
    {
      "affs": [
        2
      ],
      "name": "Yevheniia Basova"
    },
    {
      "affs": [
        4
      ],
      "name": "Oksana Chukova"
    },
    {
      "affs": [
        5
      ],
      "name": "Paweł Zawadzki"
    },
    {
      "affs": [
        3
      ],
      "name": "Igor Iatsunskyi"
    },
    {
      "affs": [
        6
      ],
      "name": "Marek Nowicki"
    },
    {
      "affs": [
        5
      ],
      "name": "Rafał Talar"
    },
    {
      "affs": [
        7
      ],
      "name": "Mikołaj Kościński"
    },
    {
      "affs": [
        8
      ],
      "name": "Mitchell J.B. Nancarrow"
    },
    {
      "affs": [
        9
      ],
      "name": "Sergiy Dobrotvorskiy"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/cfnd1sebywssa.bib",
  "cited_by": 0,
  "doi": "10.1016/j.apsadv.2026.101050",
  "fulltext_url": "http://www.sciencedirect.com/science/article/pii/S2666523926001200",
  "id": "cfnd1sebywssa",
  "issns": [
    "2666-5239"
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  "landing_url": "https://doi.org/10.1016/j.apsadv.2026.101050",
  "language": "en",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "lcc",
      "TA401-492"
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    [
      "lcc",
      "TP250-261"
    ],
    [
      "openalex",
      "2206|Laser Material Processing Techniques"
    ]
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  "openalex": "W7212068370",
  "pdf_url": null,
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-24",
  "publisher": "Elsevier",
  "ris": "https://research.draconitic.com/paper/cfnd1sebywssa.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T13:44:31Z",
      "native_id": "63ce4fd4ace0450e90677ee1dc029323",
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      "url": "https://doi.org/10.1016/j.apsadv.2026.101050"
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  "subjects": [
    {
      "field": "chemistry",
      "origin": "lcc:TP250-261",
      "subfield": "electrochemistry-energy"
    }
  ],
  "title": "Reflectivity and microrelief transitions in femtosecond laser-induced Grey and Black AISI 321 stainless steel surfaces",
  "title_text": "Reflectivity and microrelief transitions in femtosecond laser-induced Grey and Black AISI 321 stainless steel surfaces",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T13:44:31Z",
  "url": "https://research.draconitic.com/paper/cfnd1sebywssa",
  "venue": "Applied Surface Science Advances",
  "versions": []
}