Abstract-High-precision digital terahertz phase manipulation within a multichannel field perturbation coding chip

 

Hongxin Zeng, Huajie Liang, Yaxin Zhang, Lan Wang, Shixiong Liang, Sen Gong, Zheng Li, Ziqiang Yang, Xilin Zhang, Feng Lan, Zhihong Feng, Yubin Gong, Ziqiang Yang, Daniel M. Mittleman

 

Fig. 1: MFPCC architecture and its high-precision terahertz phase manipulation function.

Fig. 2: Perturbation and phase shift of a single 2DEG-PMU with 0 and 1 states.

https://www.nature.com/articles/s41566-021-00851-6

Direct phase modulation is one of the most urgent and difficult issues in the terahertz research area. Here, we propose a new method employing a two-dimensional electron gas (2DEG) perturbation microstructure unit coupled to a transmission line to realize high-precision digital terahertz phase manipulation. We induce local perturbation resonances to manipulate the phase of guided terahertz waves. By controlling the electronic transport characteristics of the 2DEG using an external voltage, the strength of the perturbation can be manipulated, which affects the phase of the guided waves. This external control permits electronic manipulation of the phase of terahertz waves with high precision, as high as 2−5° in the frequency range 0.26–0.27 THz, with an average phase error of only 0.36°, corresponding to a timing error of only 4 fs. Critically, the average insertion loss is as low as 6.14 dB at 0.265 THz, with a low amplitude fluctuation of 0.5 dB, so the device offers near-ideal phase-only modulation.

Abstract-High-precision digital terahertz phase manipulation within a multichannel field perturbation coding 2DEG meta-chip

Hongxin Zeng, Huajie Liang, Yaxin Zhang, Ziqiang Yang, Feng Lan, Shixiong Liang, Zheng Li, Lan Wang, Xilin Zhang, Sen Gong, Yubin Gong, Ziqiang Yang, 

https://www.researchsquare.com/article/rs-92448/v1

Terahertz phase manipulation has always been based on direct coupling of the resonance of quasi-optical terahertz waves with metamaterials, which is accompanied by unnecessary amplitude modulation, thus limiting the accuracy of phase manipulation and its application in monolithic integrated systems. Here, we propose a coding meta-chip composed of transmission lines and two-dimensional electron gas (2DEG) meta-atoms, wherein local perturbation resonances are induced to manipulate the phase of terahertz waves. By controlling the electronic transport characteristics of the 2DEG with external voltages, the intensity of the perturbation can be manipulated, which affects the transmission phase of the waves. More importantly, the perturbation resonances induced by different meta-atoms can be coupled so that through digital coding of the perturbation state of 2DEG meta-atoms, the terahertz wave transmission phase can be manipulated with high precision. As a result, phase manipulation with different precisions from 2° to 5° is observed from 0.26 to 0.27 THz, where the average phase error is only 0.36°, and the maximum root mean square of the transmittance is 0.36 dB. This high-precision phase manipulation via field coding has great application potential in the fields of beamforming, wireless communication, and high-resolution imaging.

Abstract-High-speed efficient terahertz modulation based on tunable collective-individual state conversion within an active 3nm-two dimensional electron gas metasurface

Yuncheng Zhao, Lan Wang, Yaxin Zhang, Shen Qiao, Shixiong Liang, Xilin Zhang, Xiaoqing Guo, Zhihong Feng, Feng Lan, Zhi Chen, Xiaobo Yang, Ziqiang Yang,

https://pubs.acs.org/doi/abs/10.1021/acs.nanolett.9b01273#

Terahertz (THz) modulators are always realized by dynamically manipulating the conversion between different resonant modes within a single unit cell of an active metasurface. In this paper, to achieve real high-speed THz modulation, we present a staggered netlike two-dimensional electron gas (2DEG) nanostructure composite metasurface that has two states: a collective state with massive surface resonant characteristics and an individual state with meta-atom resonant characteristics. By controlling the electron transport of the nanoscale 2DEG with an electrical grid, collective-individual state conversion can be realized in this composite metasurface. Unlike traditional resonant mode conversion confined in meta-units, this state conversion enables the resonant modes to be flexibly distributed throughout the metasurface, leading to a frequency shift of nearly 99% in both the simulated and experimental transmission spectra. Moreover, such a mechanism can effectively suppress parasitic modes and significantly reduce the capacitance of the metasurface. Thereby, this composite metasurface can efficiently control the transmission characteristics of THz waves with high-speed modulations. As a result, 93% modulation depth is observed in the static experiment and modulated sinusoidal signals up to 3 GHz are achieved in the dynamic experiment while the -3dB bandwidth can reach up to 1GHz. This tunable collective-individual state conversion may have great application potential in wireless communication and coded imaging.

Abstract-Dual-band refractometric terahertz biosensing with intense wave-matter-overlap microfluidic channel

Feng Lan, Feng Luo, Pinaki Mazumder, Ziqiang Yang, Lin Meng, Zhengqiang Bao, Jun Zhou, Yaxin Zhang, Shixiong Liang, Zongjun Shi, Abdur Rauf Khan, Ziqi Zhang, Luyang Wang, Jing Yin, and Hongxin Zeng

Fig. 1 (a) Schematic diagram of the microfluidic sensor, (b) microscopic image of the meta-atoms, (c) resonant unit.

https://www.osapublishing.org/boe/fulltext.cfm?uri=boe-10-8-3789&id=415013

We theoretically and experimentally demonstrate a label-free terahertz biosensor with ultrahigh sensitivity and distinctive discretion. By constructing a metal-air-metal (MAM) metamaterial perfect absorber (MPA) with a metallic paired-ring resonator array, a hollow microfluidic channel, and a backed reflector, a novel dual-band absorptive sensing platform is proposed in the THz range. The near field coupling by dipole-induced trapped modes and the magnetic momentum caused a vertical to transverse power flux that dramatically enhanced the electromagnetic field on top of the metasurface and in the microfluidic channel, respectively. Both the resonant modes exhibit perfect absorption and produce ultrahigh normalized sensitivities of 0.47/RIU (refractive index unit, RIU) and 0.51/RIU at 0.76 THz and 1.28 THz, respectively. Compared with conventional microfluidic sensors, the salient advantages of our design are the perfect spatial overlap for light-matter interaction and polarization insensitivity. Characterized by THz time domain spectroscopic absorption quantification measurements with different concentrations of bovine serum albumin (BSA), the proposed sensor exhibits promising applications in microfluidic biosensing.

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

Abstract-The Influence on the Q Value of the THz Meta-surface From the Tip Charge Accumulation Coupling

Han Sun,  Lan Wang, Yaxin Zhang, Feng Lan, Shixiong Liang, Kang Xue, Ziqiang Yang,

https://ieeexplore.ieee.org/document/8691625

With the adventure of metamaterials, there has been a tremendous advancement in the manipulation of the terahertz (THz) wave. However, the excitation of high-Q-factor resonance has been a great challenge in traditional metamaterials due to the ohmic and radiation losses. In this paper, the influence of the tip charge accumulation effect on the high-Q value meta-surface has been studied within the triangular array meta-surface. It is found that when the tip charges accumulation resonance from each pair of triangular units can couple with each other to construct a significant resonant mode which could trap more energy to achieve higher Q value. Moreover, the stacking of the induced charges distributed at the surface of the meta-unit making the coupling strength is further increased so that the strong tip charge accumulation effect could also affect the Q-value. The experiment verified this phenomenon, which shows the stronger coupling resonance and tip charges accumulation could result in the enhancement of the Q-value. This research has potential applications in high-Q THz devices.

Abstract-Ultrasensitive dual-band terahertz sensing with metamaterial perfect absorber

Weihao Zhang,   Feng Lan,  Jinyang Xuan,   Pinanki Mazumder,  Mahdi Aghadjani,  Ziqiang Yang,  Lin Men

https://ieeexplore.ieee.org/document/8247404/

Due to the weak energy storage characteristics of the monolayer metamaterial, how to increase the sub-wavelength scale interaction between biological or chemical samples and terahertz wave on sufficient sensitivity premise becomes the key scientific problems in the study of terahertz sensing technology. In this paper, an ultrasensitive dual-band spectral terahertz sensor with polarization insensitive metamaterial perfect absorber (MPA) is demonstrated. A double-ring shaped metal microstructure integrated with microfluidic channel is applied in the polarization sensitive terahertz sensor. The numerical results show that the normalized sensitivity of refractive index unit 0.638/RIU with mode A and 0.582/RIU with mode B are obtained at 1.04THz and 0.506THz, respectively. The absorptive sensing mechanism is elucidated by the electric field and surface current distributions. Compared to other metamaterials (MMs) based terahertz sensors, the proposed MPA sensor with significantly confined field, enhanced sensitivity and polarization insensitivity is much more suitable for label-free terahertz probing of fluidic matter detection.

Abstract-Enhanced quadruple-resonant terahertz metamaterial with asymmetric hybrid resonators

Minglei Shi, Feng Lan, Pinaki Mazumder, Mahdi Aghadjani, Ziqiang Yang, Lin Meng, Jun Zhou,

https://www.sciencedirect.com/science/article/pii/S0925346717306997

This paper presents the design, fabrication and investigation of a quadruple-resonant terahertz metamaterial that comprises two different Electric-inductance capacitance (ELC) resonators in a vertical configuration. Owing to asymmetric electric field coupling between the two resonators, the combined structure exhibits better performance in terms of transmission minima and bandwidths than the individual particles. The distributions of the surface current and electric field reveal quasi-quadrupole resonance, electric dipolar resonance and coupling between these resonances at different resonant frequencies. Moreover, the resonant frequencies are tunable by adjusting the corresponding geometrical parameters. Above all, the excellent performance of the proposed structure makes it promising for application in multiband terahertz devices.

Abstract-Terahertz dual-resonance bandpass filter using bilayer reformative complementary metamaterial structures

Feng Lan, Ziqiang Yang, Limei Qi, Xi Gao, and Zongjun Shi  »View Author Affiliations

Optics Letters, Vol. 39, Issue 7, pp. 1709-1712 (2014)
http://dx.doi.org/10.1364/OL.39.001709

http://www.opticsinfobase.org/ol/abstract.cfm?uri=ol-39-7-1709

A dual-resonance frequency selective surface filter in the THz range that uses bilayer modified complementary metamaterial structures is proposed in this Letter. The bandpass filter, with dual bands centered at 0.315 and 0.48 THz, uses a single crystal quartz substrate and is simulated, fabricated, and measured. To minimize the manufacturing risks of working with fragile and thin quartz substrates, efforts have been made to improve the transmission frequency response features at realizable substrate thicknesses. Experimental results from 0.1 to 0.6 THz measured by THz time-domain spectroscopy show excellent agreement with the simulation results.

© 2014 Optical Society of America