Abstract-Active thermal modulation of electromagnetically induced transparency at terahertz frequencies

 

Wentao Zhang, Hongyang Li, Shan Yin, Wei Huang, Xintong Shi, Yuting Zhang, 

https://www.spiedigitallibrary.org/journals/optical-engineering/volume-59/issue-12/127111/Active-thermal-modulation-of-electromagnetically-induced-transparency-at-terahertz-frequencies/10.1117/1.OE.59.12.127111.short?SSO=1

We present thermal control of electromagnetically induced transparency (EIT) by actively modulating the dark mode in terahertz (THz) metamaterials, including a cut wire and a split-ring resonator (SRR). By integrating indium antimonide (InSb) into the SRR and increasing the temperature, the active modulation of EIT is realized. The coupling mechanism is numerically analyzed through the coupled oscillator model, and the result of fitting the EIT intensity agrees well with the simulation results when the temperature changes from 200 to 240 K. By analyzing the electric field distribution, the physical mechanism is the change in the damping rate of the dark mode resonator due to the increase in InSb temperature. Our work has practical significance in designing tunable THz functional devices.

© 2020 Society of Photo-Optical Instrumentation Engineers (SPIE) 0091-3286/2020/$28.00 © 2020 SPIE

Abstract-Actively tunable terahertz electromagnetically induced transparency analogue based on vanadium-oxide-assisted metamaterials

• Zhaojian Zhang,  
• Junbo Yang, 
• Yunxin Han, 
• Xin He, 
• Jingjing Zhang, 
• Jie Huang, 
• Dingbo Chen, 
• Siyu Xu,  
• Wanlin Xie 
• • 
    

https://link.springer.com/article/10.1007/s00339-020-3374-2

We investigate the active control of electromagnetically induced transparency (EIT) analogue based on terahertz (THz) metamaterials integrated with vanadium oxide(VO2). Due to the insulator-to-metal transition of VO2, the amplitude of EIT peak can be actively modulated with significant modulation depth. Meanwhile the group delay within the transparent window can also be dynamically tuned, bringing the active control of slow light effect. Furthermore, we also introduce independently tunable transparent peaks based on double-peak EIT, and the group delay within each transparent window can also be independently controlled. Finally, based on broadband EIT, the active tuning toward quality factor of EIT is also realized. This work introduces active EIT control with multiple degree of freedom by employing VO2, and can find potential applications in future wireless THz communication systems as multi-channel filters, switches, spacers, logic gates and modulators.

Abstract-All-dielectric metamaterial analogue of electromagnetically induced transparency and its sensing application in terahertz range

Tian Ma, Qiuping Huang, Hongchuan He, Yi Zhao, XIaoxia Lin, and Yalin Lu

Fig. 2 (a) Schematic of the all-dielectric metamaterial composed of two asymmetric split ring resonators. Inset: top view of the unit cell. All dimensions shown here are $h=100\mu m,$ $t=30\mu m,$ $P_x=400\mu m,$ $P_y=400\mu m,$ $R_1=75\mu m,$ $R_2=75\mu m,$ $\alpha =160°,$ and $\beta =120°.$ (b) Microscopy of the fabricated sample. Bars refer to 500μm. (c) Transmission spectra and (d) corresponding group delay of the proposed metamaterial

http://aoip.osa.org/oe/abstract.cfm?uri=oe-27-12-16624

A novel electromagnetically induced transparency (EIT) all-dielectric metamaterial is proposed, fabricated, and characterized. The unit cell of the proposed metamaterial comprises of two asymmetric split ring resonators (a-SRRs) positioned with a mirror symmetry. The asymmetric nature of a-SRRs results from the length difference of two arcs. Optical properties of the fabricated metamaterial are investigated numerically using finite difference method, as well as experimentally using a terahertz time-domain spectroscopy. The results confirm that the proposed metamaterial exhibits an EIT transparent window in the frequency range around 0.78THz with a Q-factor of ~75.7 and a time-delay up to ~28.9ps. Theoretical investigations show that EIT effects in our metamaterial are achieved by hybridizing two bright modes in the same unit cell, which are aroused by the excitation of magnetic moments. We also confirm that the proposed metamaterial has great potential for sensing applications with high sensitivity and high figure of merit (FOM), which guarantees potential applications in in situ chemical and biological sensing.

© 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Abstract-Isotropic wide-angle analog of electromagnetically induced transparency in a terahertz metasurface

Zhengyong Song, Qiongqiong Chu, Qing Huo Liu

https://www.sciencedirect.com/science/article/pii/S0167577X18306025

We present a terahertz classical analog of electromagnetically induced transparency by means of single-layer metamaterial consisting of two closed square ring. The narrow transparency peak is mainly caused by the excitation of antiparallel currents in different rings. Because of symmetry configuration, the designed metamaterial possesses stable polarization-independent and wide-angle transmission spectral features. Moreover, the design has a simple structure ideally suitable for the current planar micro- and nano-fabrications.

Abstract-Dynamically tunable metamaterial analogue of electromagnetically induced transparency with graphene in the terahertz regime

Tingting Liu

https://arxiv.org/abs/1712.05525

A novel mechanism to realize dynamically tunable electromagnetically induced transparency (EIT) analogue in the terahertz (THz) regime is proposed. By putting the electrically controllable monolayer graphene under the dark resonator, the amplitude of the EIT resonance in the metal-based metamaterial can be modulated substantially via altering the Fermi level of graphene. The amplitude modulation can be attributed to the change in the damping rate of the dark mode caused by the recombination effect of the conductive graphene. This work provides an alternative way to achieve tunable slow light effect and has potential applications in THz wireless communications.

Abstract-Metamaterials: Electromagnetically Induced Transparency Analogue by Self-Complementary Terahertz Meta-Atom

1. Hyunseung Jung¹, 
2. Chihun In², 
3. Hyunyong Choi² and
4. Hojin Lee^1,*
5. 1. ^{http://onlinelibrary.wiley.com/doi/10.1002/adom.201670019/abstract}

Article first published online: 20 APR 2016

DOI: 10.1002/adom.201670019

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Self-complimentary terahertz meta-atoms are developed by combining cut-wire resonators and their pseudo-complimentary structure to resonate with incident terahertz waves simultaneously. H. Lee and co-workers successfully present this self-complimentary single meta-atom as a new way to achieve electromagnetically induced transparency analogues on page 627. This is achieved with the localized H-field at the resonance to focus E-fields into the hole of the pseudo-complimentary cut-wire within a unit cell.

Abstract-Electromagnetically Induced Transparency Analogue by Self-Complementary Terahertz Meta-Atom

1. Hyunseung Jung¹, 
2. Chihun In², 
3. Hyunyong Choi² and
4. Hojin Lee^1,*

Article first published online: 19 JAN 2016

DOI: 10.1002/adom.201500620

© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

http://onlinelibrary.wiley.com/doi/10.1002/adom.201500620/abstract

In the past years, many researchers have tried to realize the electromagnetically induced transparency (EIT) phenomena from the metamaterial arrays for the attractable applications such as slow light devices, novel optical communication systems, and nonlinear optical devices. Most of metamaterial enabled EIT analogues reported so far are based on the destructive interference between the bright and dark meta-atoms. Whether they are located on the same plane or off the plane, EIT-like properties can be achieved only by breaking the symmetry between the bright and dark meta-atoms. In this study, a novel self-complimentary terahertz meta-atom is developed by combining cut-wire resonators and its pseudo-complimentary pattern within a single meta-atom. From the measurement results, it is verified that the proposed meta-atom can exhibit EIT-like phenomenon within a single unit cell by controlling the focus of the electric field induced by the incident terahertz waves within the self-complimentary meta-atom cell as predicted by the numerical simulation as well as by the theoretical forced oscillation model.

Abstract-Dual-mode electromagnetically induced transparency and slow light in a terahertz metamaterial

Kun Zhang, Cheng Wang, Ling Qin, Ru-Wen Peng, Di-Hu Xu, Xiang Xiong, and Mu Wang  »View Author Affiliations
http://www.opticsinfobase.org/ol/abstract.cfm?uri=ol-39-12-3539

Optics Letters, Vol. 39, Issue 12, pp. 3539-3542 (2014)
http://dx.doi.org/10.1364/OL.39.003539

In this Letter, we construct a metamaterial with dual-mode electromagnetically induced transparency (EIT)-like behavior by introducing “bright atoms,” “quasi-dark atoms,” and “dark atoms” simultaneously. The dual-mode EIT-like behavior has been demonstrated both experimentally and theoretically in terahertz (THz) regime. At two EIT-like modes, slow light is also observed as two time-delayed wave packets, and the effective group refractive index can reach 102. Furthermore, stable dual-mode EIT-like behavior is verified in this metamaterial for a wide range of oblique incident angles. Our work provides a design approach to mimic dual-mode EIT, and such an approach may achieve potential applications on miniaturized and versatile THz devices.

© 2014 Optical Society of America