EPJ B Highlight - Turning graphene into light nanosensors

Absorption on the plane of incident angle and wavelength.

Tuning the graphene embedded in a photonic crystal by varying the external temperature can transform it into a light-sensitive sensor

Graphene has many properties; it is e.g. an extremely good conductor. But it does not absorb light very well. To remedy this limiting aspect of what is an otherwise amazing material, physicists resort to embedding a sheet of graphene in a flat photonic crystal, which is excellent for controlling the flow of light. The combination endows graphene with substantially enhanced light-absorbing capabilities. In a new study published in EPJ B, Arezou Rashidi and Abdolrahman Namdar from the University of Tabriz, Iran demonstrate that, by altering the temperature in such a hybrid cavity structure, they can tune its capacity for optical absorption. They explain that it is the thermal expansion and thermo-optical effects which give the graphene these optical characteristics. Potential applications include light sensors, ultra-fast lasers, and systems capable of modulating incoming optical beams.

The authors study the light absorption of the material as a function of temperature, the chemical energy potential, the light polarisation and its incidence angles. To do so, they use a modelling method called the transfer matrix method. They find that for normal light incidence, there is enhanced absorption at room temperature, while the absorption peak is shifted toward the red as the temperature increases.

As light comes in at an angle, the authors show that the absorption peaks are sensitive to the incident angles as well as the polarisation state of the light. They also find that by increasing the incident angle, the peak wavelength is shifted toward the blue.

They conclude that the peak wavelength can be controlled by varying either the temperature or incident angle, as well as the chemical energy potential of graphene. This shows that there are a number of tunable features that could be exploited for the design of graphene-based nano-devices, such as temperature-sensitive absorbers and sensors.

As Editors of the volume 108 of EPJ Web of Conferences, we ask you personally to accept our deep gratitude. It was a great favour to work with you and the EPJ Web of Conferences team on all stages involved in the publication of the post-processed Proceedings of MMCP 2015. We have been very satisfied with your courteous consideration of every our demand, without exception, with your contribution to finding the most convenient outcomes. Your determination to speed up the publishing process is highly appreciated.

George Adam, JINR Dubna, Russia
Michal Hnatic, Institute of Experimental Physics, Slovak Republic
Ján Buša, Technical University of Kosice, Slovak Republic
Co-editors of MMCP 2015, EPJ Web of Conferences vol. 108, 2016

ISSN: 2100-014X (Electronic Edition)

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