بررسی تاثیر زمان واهلش بر رفتار پلاسمون- پلاریتون ها در نانولایه‌ی گرافنی

نوع مقاله : مقاله پژوهشی

نویسندگان

گروه فیزیک، دانشکده علوم، دانشگاه سیستان و بلوچستان، زاهدان، ایران

چکیده

: پلاسمون- پلاریتون­ها باعث جایگزیدگی نور در ناحیه­ای می­شوند که ابعاد آن کسری از طول موج نور است. این امر
برهم­کنش نور با ماده را افزایش می ­دهد که برای کاربردهای حسگری مناسب است. بر این اساس در این مقاله پلاسمون- پلاریتون­ها در یک نانولایه­ ی گرافنی در ناحیه طیفی فروسرخ متوسط بررسی شدند. به دلیل اینکه بردار موج پلاسمون- پلاریتون­ها در گرافن خیلی بزرگتر از بردار موج در فضای آزاد است، برای تحریک پلاسمون- پلاریتون­ها در گرافن از توری پراش استفاده شد. برای بررسی تاثیر زمان واهلش الکترون­ها روی پلاسمون- پلاریتون­ها در گرافن زمان واهلش از  تا  تغییر داده شد و با حل معادله موج الکترومغناطیسی، تحریک پلاسمون- پلاریتون­ها در گرافن شبیه­سازی شد. نتایج نشان می­دهند که با کاهش زمان واهلش جایگزیدگی و شدت پلاسمون- پلاریتون­ها در گرافن کاهش می­یابند ولی تغییر زمان واهلش تاثیری بر دوره­ی تناوب پلاسمون- پلاریتون­ها در گرافن ندارد. همچنین، بررسی طیف بازتاب، عبور و جذب نشان می­دهد که شدت و محل قله­های طیف بازتاب محک مناسبی برای برآورد کیفی جایگزیدگی و برآورد کمی طول موج تحریک پلاسمون- پلاریتون­ها در گرافن است.

کلیدواژه‌ها


عنوان مقاله [English]

Investigating the effect of relaxation time on the behaviour of plasmon-polaritons in a nanolayer graphene

نویسندگان [English]

  • Fatemeh Molavi-Vardanjani
  • Naser Hatefi-Kargan
Department of physics, Faculty of Science, University of Sistan and Baluchestan, Zahedan, Iran
چکیده [English]

Plasmon-polaritons can confine an optical wave to a region with dimensions much smaller than the wavelength of the wave in free space. This increases the interaction of optical radiation with material that is suitable for sensing applications. For this reason, in this paper plasmon-polaritons in a nanolayer graphene at mid infrared spectral wavelengths are investigated. Owing to the large wavenumber of plasmon-polaritons in graphene relative to the wavenumber of an optical wave with the same frequency in free space, diffraction grating is used for exciting plasmon-polaritons in graphene. For investigating the effect of relaxation time on the plasmon-polaritons in graphene, relaxation time was varied from  to  and plasmon-polaritons in graphene were simulated by solving electromagnetic wave equation. The results show that while the variation of relaxation time does not affect the period of plasmon-polaritons in graphene, with the decrease of relaxation time confinement and intensity of the plasmon-polaritons in graphene decrease. In addition investigating the reflectance, transmittance and absorption spectra show that the intensity and the location of pick points in the reflection spectra are appropriate for qualitative determination of confinement, and quantitative determination of excitation wavelength of plasmon-polaritons in graphene.

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