Abstract-Tunability of temperature-dependent absorption in a graphene-based hybrid nanostructure cavity

Arezou Rashidi, Abdolrahman Namdar

https://link.springer.com/article/10.1140%2Fepjb%2Fe2018-80506-2

Enhanced absorption is obtained in a hybrid nanostructure composed of graphene and one-dimensional photonic crystal as a cavity in the visible wavelength range thanks to the localized electric field around the defect layers. The temperature-induced wavelength shift is revealed in the absorption spectra in which the peak wavelength is red-shifted by increasing the temperature. This temperature dependence comes from the thermal expansion and thermo-optical effects in the constituent layers of the structure. Moreover, the absorption peaks can be adjusted by varying the incident angle. The results show that absorption is sensitive to TE/TM polarization and its peak values for the TE mode are higher than the TM case. Also, the peak wavelength is blue-shifted by increasing the incident angle for both polarizations. Finally, the possibility of tuning the absorption using the electro-optical response of graphene sheets is discussed in detail. We believe our study may be beneficial for designing tunable graphene-based temperature-sensitive absorbers.

Abstract-Terahertz surface plasmon-polaritons in one-dimensional graphene based Fibonacci photonic superlattices

Abdolrahman Namdar, Rana Feizollahi Onsoroudi, Habib Khoshsima, Mostafa Sahrai

https://www.sciencedirect.com/science/article/pii/S074960361732459X

The surface plasmon-polaritons in one-dimensional graphene-based Fibonacci photonic superlattices in the terahertz frequency range have been theoretically investigated. Our numerical study shows that surface plasmon-polaritons can be realized in both transverse electric and transverse magnetic polarizations. It is shown that these modes are manageable by varying the quasi-periodic generation orders which play a critical role in the occurrence of surface modes. In addition, the effect of thickness of cap layer and chemical potential of graphene sheets on surface plasmon-polaritons and their electric field distribution are studied. We have verified the excitation of surface plasmon-polaritons by using the attenuated total reflection method. This inspection confirms that all the predicted surface modes in the dispersion curves are actually excitable with this method.

Abstract-Magnetically tunable enhanced absorption of circularly polarized light in graphene-based 1D photonic crystals

Arezou Rashidi, Abdolrahman Namdar, and Reza Abdi-Ghaleh

We theoretically investigate the magnetic-field-induced terahertz absorption enhancement of a graphene-based one-dimensional photonic crystal using the 4×4$4\times 4$ transfer matrix method for the circular polarization of light. The results show that the magnetically tunable absorption of the structure depends on the circular polarization state, magnetic circular dichroism, and, interestingly, absorption behaviors of right-handed and left-handed circularly polarized light interchange by changing the direction of the magnetic field. These properties can be used to design the circular-polarization-based sensors.

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