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<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Publishing DTD v1.3 20210610//EN" "https://jats.nlm.nih.gov/publishing/1.3/JATS-journalpublishing1-3.dtd">
<article article-type="meeting-report" dtd-version="1.3" xml:lang="ru">
  <front>
    <journal-meta>
      <journal-title-group>
        <journal-title>St. Petersburg Polytechnic University Journal: Physics and Mathematics</journal-title>
        <trans-title-group xml:lang="ru">
          <trans-title>Научно-технические ведомости СПбГПУ. Физико-математические науки</trans-title>
        </trans-title-group>
      </journal-title-group>
      <issn pub-type="epub">2304-9782, 2618-8686, 2405-7223</issn>
    </journal-meta>
    <article-meta>
      <article-id pub-id-type="publisher-id">44</article-id>
      <article-id pub-id-type="doi">10.18721/JPM.183.144</article-id>
      <title-group>
        <article-title>The investigation of Laguerre–Gaussian (0,1) mode focusing in the near-field diffraction by subwavelength variable-height ring gratings</article-title>
        <trans-title-group xml:lang="ru">
          <trans-title>Исследование фокусировки мод Лагерра–Гаусса (0,1) в ближней зоне дифракции субволновыми кольцевыми решетками переменной высоты</trans-title>
        </trans-title-group>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <contrib-id contrib-id-type="orcid">0000-0003-2282-3895</contrib-id>
          <name>
            <surname>Savelyev Dmitry</surname>
            <given-names>Dmitry</given-names>
          </name>
          <email>dmitrey.savelyev@yandex.ru</email>
        </contrib>
      </contrib-group>
      <pub-date publication-format="electronic" date-type="pub" iso-8601-date="2025-12-10">
        <day>10</day>
        <month>12</month>
        <year>2025</year>
      </pub-date>
      <volume>18</volume>
      <issue>3.1</issue>
      <fpage>222</fpage>
      <lpage>225</lpage>
      <abstract xml:lang="en">
        <p>The parameters of the height of individual zones of subwave ring gratings were established in this paper for which the formation of a long light needle (7.85 wavelengths) is observed in the near diffraction zone with azimuthal polarization of laser radiation. The possibility of reducing the focal spot size to 0.31 wavelengths with circular polarization of the Laguerre–Gauss mode (0,1) was also shown.</p>
      </abstract>
      <kwd-group xml:lang="en">
        <kwd>Laguerre–Gaussian mode</kwd>
        <kwd>optical needle</kwd>
        <kwd>FDTD</kwd>
        <kwd>subwavelength ring gratings</kwd>
        <kwd>polarization</kwd>
      </kwd-group>
    </article-meta>
  </front>
</article>
