In order to obtain a dynamically adjustable plasmon induced transparency (PIT) phenomenon in non-contact way, we theoretically and numerically investigate the thermal tunable PIT by taking into account of electrons and phonons interaction in graphene metamaterial. The novel structure consists of two hollow square graphene and a rectangular strip in right middle, each of them acting as a bright mode. To fully explore the physical origin of the transparency window, the Lorentz coupled oscillator theory is employed. Good agreement can be achieved with the numerical results, which further verifies our calculations. To alter the PIT effect, the influence on the transparency window with different temperature and polarization angle are elaborately examined. The bandwidth of the transparent window gets wider with the lower temperature and switchable transparent window appears with varied polarization angle. As a potential application in the slow light device, the group index and group delay are also calculated with the temperature from 60 K to 500 K. Our proposed thermal tunable PIT structure may open up a new avenue in the application of controllable optical filters, switchers and optical memories.

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A distinct plasmon-induced transparency (PIT) window has been realized in our novel design of |+|-shaped graphene metamaterials, which consist of two identical graphene strips and a cross-shaped graphene resonator in the right middle. The two strips serve as the dark resonator, and the cross-shaped graphene plays the bright one. Active control of the PIT window can be modulated from the on state to the off state only by breaking structure symmetry. Furthermore, the PIT window can be dynamically adjusted with different Fermi energies in a noncontact way. More importantly, the proposed metamaterial structure achieves a maximum group delay of 13.28 ps, which is much higher than that in the previous paper. In the case of sensing application, the position of the PIT window has been investigated with different embedded media, and it shows a linear function of the refraction index. This study may open up new avenues for the development of highly integrated optical filters, optical sensors, or integrated optical switches.

In this work, plasmon-induced transparency has been realized with graphene metamaterial consisting of double asymmetric L strips. Due to the weak hybridization between this two L strip resonator, a clear transparency window on the transmission spectrum of the originally opaque frequency range can be realized. With a Lorentz coupled oscillator model, our theoretical results of the transmission spectra agree well with the numerical calculations. Moreover, the transparency window can be dynamically modulated via regulating the Fermi energy and carrier mobility. The reflection and absorption spectrum has also been analyzed concretely, and its absorption rate approaches as high as 50%, which provides a solid application in terahertz absorbers. According to the effective medium theory, the sensitivity of the transparency window as a function of the surrounding medium embodies a linear relationship. As for its dispersion behavior, the group index of the structure can reach up to 1125. This work shadows a fascinating application in the area of highly integrated sensor devices, filters or absorbers.

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