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<article article-type="research-article" dtd-version="1.3" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xml:lang="ru"><front><journal-meta><journal-id journal-id-type="publisher-id">vestifm</journal-id><journal-title-group><journal-title xml:lang="ru">Известия Национальной академии наук Беларуси. Серия физико-математических наук</journal-title><trans-title-group xml:lang="en"><trans-title>Proceedings of the National Academy of Sciences of Belarus. Physics and Mathematics Series</trans-title></trans-title-group></journal-title-group><issn pub-type="ppub">1561-2430</issn><issn pub-type="epub">2524-2415</issn><publisher><publisher-name>The Republican Unitary Enterprise Publishing House "Belaruskaya Navuka"</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.29235/1561-2430-2022-58-2-237-244</article-id><article-id custom-type="elpub" pub-id-type="custom">vestifm-647</article-id><article-categories><subj-group subj-group-type="heading"><subject>Research Article</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="ru"><subject>ФИЗИКА</subject></subj-group><subj-group subj-group-type="section-heading" xml:lang="en"><subject>PHYSICS</subject></subj-group></article-categories><title-group><article-title>Эффекты насыщения усиления в квантово-каскадных лазерах ТГц-диапазона</article-title><trans-title-group xml:lang="en"><trans-title>Gain saturation effects in THz quantum cascade lasers</trans-title></trans-title-group></title-group><contrib-group><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Ушаков</surname><given-names>Д. В.</given-names></name><name name-style="western" xml:lang="en"><surname>Ushakov</surname><given-names>D. V.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Ушаков Дмитрий Владимирович – кандидат физико-математических наук, доцент, декан факультета радиофизики и компьютерных технологий</p><p>пр. Независимости, 4, 220030, Минск</p></bio><bio xml:lang="en"><p>Dmitrii V. Ushakov – Ph. D. (Physics and Mathematics), Associate Professor, Dean of the Faculty of Radiophysics and Computer Technologies</p><p>4, Nezavisimosti Ave., 220030, Minsk</p><p> </p></bio><email xlink:type="simple">UshakovDV@bsu.by</email><xref ref-type="aff" rid="aff-1"/></contrib><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Афоненко</surname><given-names>А. А.</given-names></name><name name-style="western" xml:lang="en"><surname>Afonenko</surname><given-names>A. A.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Афоненко Александр Анатольевич – доктор физико-математических наук, доцент, заведующий кафедрой квантовой радиофизики и оптоэлектроники</p><p>пр. Независимости, 4, 220030, Минск</p></bio><bio xml:lang="en"><p>Alexander A. Afonenko – Dr. Sc. (Physics and Mathematics), Associate Professor, Head of the Department of Quantum Radiophysics and Optoelectronics</p><p>4, Nezavisimosti Ave., 220030, Minsk</p></bio><email xlink:type="simple">afonenko@bsu.by</email><xref ref-type="aff" rid="aff-1"/></contrib><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Хабибуллин</surname><given-names>Р. А.</given-names></name><name name-style="western" xml:lang="en"><surname>Khabibullin</surname><given-names>R. A.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Хабибуллин Рустам Анварович – кандидат физико-математических наук, ученый секретарь</p><p>Нагорный проезд, 7, стр. 5, 117105, Москва</p></bio><bio xml:lang="en"><p>Rustam A. Khabibullin – Ph. D. (Physics and Mathematics), Senior Researcher</p><p>7, building 5, Nagorny proezd, 117105, Moscow</p></bio><email xlink:type="simple">khabibullin@isvch.ru</email><xref ref-type="aff" rid="aff-2"/></contrib><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Кононенко</surname><given-names>В. К.</given-names></name><name name-style="western" xml:lang="en"><surname>Kononenko</surname><given-names>V. K.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Кононенко Валерий Константинович – доктор физико-математических наук, профессор, профессор кафедры квантовой радиофизики и оптоэлектроники</p><p>пр. Независимости, 4, 220030, Минск</p></bio><bio xml:lang="en"><p>Valerii K. Kononenko – Dr. Sc. (Physics and Mathematics), Professor, Professor of the Department of Quantum Radiophysics and Optoelectronics</p><p>4, Nezavisimosti Ave., 220030, Minsk </p></bio><xref ref-type="aff" rid="aff-1"/></contrib><contrib contrib-type="author" corresp="yes"><name-alternatives><name name-style="eastern" xml:lang="ru"><surname>Манак</surname><given-names>И. С.</given-names></name><name name-style="western" xml:lang="en"><surname>Manak</surname><given-names>I. S.</given-names></name></name-alternatives><bio xml:lang="ru"><p>Манак Иван Степанович – кандидат физико-математических наук, доцент, доцент кафедры квантовой радиофизики и оптоэлектроники</p><p>пр. Независимости, 4, 220030, Минск</p></bio><bio xml:lang="en"><p>Ivan S. Manak – Ph. D. (Physics and Mathematics), Associate Professor, Associate Professor of the Department of Quantum Radiophysics and Optoelectronics</p><p>4, Nezavisimosti Ave., 220030, Minsk</p></bio><xref ref-type="aff" rid="aff-1"/></contrib></contrib-group><aff-alternatives id="aff-1"><aff xml:lang="ru"><institution>Белорусский государственный университет</institution></aff><aff xml:lang="en"><institution>Belarusian State University</institution></aff></aff-alternatives><aff-alternatives id="aff-2"><aff xml:lang="ru"><institution>Институт сверхвысокочастотной полупроводниковой электроники имени В. Г. Мокерова РАН</institution></aff><aff xml:lang="en"><institution>V. G. Mokerov Institute of Ultra-high Frequency Semiconductor Electronics of Russian Academy of Sciences</institution></aff></aff-alternatives><pub-date pub-type="collection"><year>2022</year></pub-date><pub-date pub-type="epub"><day>05</day><month>07</month><year>2022</year></pub-date><volume>58</volume><issue>2</issue><fpage>237</fpage><lpage>244</lpage><permissions><copyright-statement>Copyright &amp;#x00A9; Ушаков Д.В., Афоненко А.А., Хабибуллин Р.А., Кононенко В.К., Манак И.С., 2022</copyright-statement><copyright-year>2022</copyright-year><copyright-holder xml:lang="ru">Ушаков Д.В., Афоненко А.А., Хабибуллин Р.А., Кононенко В.К., Манак И.С.</copyright-holder><copyright-holder xml:lang="en">Ushakov D.V., Afonenko A.A., Khabibullin R.A., Kononenko V.K., Manak I.S.</copyright-holder><license xml:lang="ru" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>Данная работа распространяется под лицензией Creative Commons Attribution 4.0.</license-p></license><license xml:lang="en" license-type="creative-commons-attribution" xlink:href="https://creativecommons.org/licenses/by/4.0/" xlink:type="simple"><license-p>This work is licensed under a Creative Commons Attribution 4.0 License.</license-p></license></permissions><self-uri xlink:href="https://vestifm.belnauka.by/jour/article/view/647">https://vestifm.belnauka.by/jour/article/view/647</self-uri><abstract><p>На основе системы балансных уравнений проведен анализ эффекта насыщения усиления в квантово-каскадных структурах с 2–4 квантовыми ямами в периоде. Показано, что параметр нелинейности уменьшается при увеличении скорости релаксации лазерных уровней, но при этом растет полный ток через структуру. Использование предложенных многофотонных дизайнов приводит к уменьшению параметра нелинейности без увеличения рабочего тока. Например, в двухфотонной схеме лазерных переходов при одинаковых вероятностях переходов и коэффициентах дифференциального усиления достигается в 2 раза более медленное насыщение коэффициента усиления с ростом плотности фотонов, что обусловливает более высокую эффективность генерации, чем в однофотонных схемах.</p></abstract><trans-abstract xml:lang="en"><p>The effect of gain saturation in quantum-cascade structures with 2–4 quantum wells per period is herein analyzed on the basis of a system of balance equations. It is shown that the nonlinearity parameter decreases with an increase in the relaxation rate of laser levels, but the total current through the structure also increases. The use of the proposed multiphoton designs leads to a decrease in the non-linearity parameter without increasing the operating current. For example, in a two-photon scheme of laser transitions with the same transition probabilities and differential gains, two times slower saturation of the gain with an increase in the photon density is achieved, which leads to a high generation efficiency than in single-photon schemes.</p></trans-abstract><kwd-group xml:lang="ru"><kwd>квантово-каскадный лазер</kwd><kwd>балансные уравнения</kwd><kwd>насыщение усиления</kwd></kwd-group><kwd-group xml:lang="en"><kwd>quantum-cascade laser</kwd><kwd>balance equations</kwd><kwd>gain saturation</kwd></kwd-group></article-meta></front><back><ref-list><title>References</title><ref id="cit1"><label>1</label><citation-alternatives><mixed-citation xml:lang="ru">Оптические свойства четырехуровнего квантового генератора / Ю. А. Ананьев [и др.] // Докл. 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