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-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.

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