{
  "abstract": "The paper presents an experimental and theoretical analysis of the effects accompanying the non-contact, non-destructive nanoscale characterization of thin-film metal–dielectric structures through the substrate, using high-amplitude picosecond acoustic pulses generated by an ultrafast laser. Time-resolved reflectivity changes ΔR(t)/R0 at 793 nm are measured in the picosecond time domain using an all-optical pump-probe setup with balanced, phase-sensitive detection tuned to 0.5 kHz. For a glass-supported nanoscale nickel film, the measurements at the glass–film interface are carried out at absorbed laser fluences ranging from 1.7 to 10.3 mJ/cm2, generating peak pressures of up to several gigapascals. The ΔR(t)/R0 signal is dominated by the resulting Brillouin oscillations at a frequency of fBO = 1/TBO = 21.5 ± 0.1 GHz within the substrate, which undergo amplitude-phase modulation due to the superposition of the individual Brillouin oscillations from the acoustic pulses leaking into the substrate after reverberating in the film. Through post-processing, the obscured ΔR(t)/R0 signal of the acoustic pulses reverberating in the film at fecho = 1/Techo = 39.1 ± 0.2 GHz is reconstructed, showing excellent agreement with the reference signal directly measured at the air–film interface. It is shown that, unlike sufficiently thick submicron films, which exhibit no amplitude-phase modulation by reverberating acoustic pulses during the first several hundred picoseconds (Techo >> TBO), nanoscale films—where Techo ≈ TBO/2—cause a significant reduction in the resulting amplitude of the Brillouin oscillations in the substrate, which reaches its minimum due to destructive interference.",
  "abstract_shown": true,
  "affiliations": [
    "Joint Institute for High Temperatures of the Russian Academy of Sciences, Izhorskaya st. 13 Bd.2, 125412 Moscow, Russia"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 1,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Sergey A. Romashevskiy",
      "orcid": "0000-0001-6061-6702"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/7gptmxmvc7q38.bib",
  "cited_by": 0,
  "doi": "10.3390/nano16201307",
  "fulltext_url": null,
  "id": "7gptmxmvc7q38",
  "issns": [
    "2079-4991"
  ],
  "landing_url": "https://www.mdpi.com/2079-4991/16/20/1307",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2211|Ultrasonics and Acoustic Wave Propagation"
    ]
  ],
  "openalex": "W7222647798",
  "pdf_url": null,
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-16",
  "publisher": "MDPI AG",
  "ris": "https://research.draconitic.com/paper/7gptmxmvc7q38.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:18:45Z",
      "native_id": "10.3390/nano16201307",
      "source": "crossref",
      "url": "https://www.mdpi.com/2079-4991/16/20/1307"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "issn:2079-4991",
      "subfield": "materials-polymers"
    }
  ],
  "title": "Reconstruction of Acoustic Echoes and Their Effect on Brillouin Oscillations in Nanoscale Characterization of Supported Thin Films by Ultrafast Photoacoustics",
  "title_text": "Reconstruction of Acoustic Echoes and Their Effect on Brillouin Oscillations in Nanoscale Characterization of Supported Thin Films by Ultrafast Photoacoustics",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:45Z",
  "url": "https://research.draconitic.com/paper/7gptmxmvc7q38",
  "venue": "Nanomaterials",
  "versions": []
}