Abstract-Terahertz-frequency temporal differentiator enabled by a high-Q resonator

Jingya Xie, Xi Zhu, Hongxiang Zhang, Xiaofei Zang, Lin Chen, Alexey V. Balakin, Alexander P. Shkurinov, and Yiming Zhu

Schematic of the experimental setup for measurements of THz integrated temporal differentiator. AWG: arbitrary waveform generators. RF&MSG: radio frequency microwave source. SGX Module: signal generator extension module. HA: horn antenna. DD: direct detector. The insets (a) and (b) are the schematic drawing of the TRR and cross-sectional view of waveguides, respectively.

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-28-6-7898

Terahertz (THz) fundamental “building blocks” equivalent to those used in multi-functional electronic circuits are very helpful for actual applications in THz data-processing technology and communication. Here, we theoretically and experimentally demonstrate a THz temporal differentiator based on an on-chip high-quality (Q) factor resonator. The resonator is made of low-loss high-resistivity silicon material in a monolithic, integrated platform, which is carefully designed to operate near the critical coupling region. The experiment demonstrates that the device can perform the first-order time derivative of the input signal electric field complex envelope at 214.72 GHz. Our investigation provides an effective approach for terahertz pulse re-shaping and real-time differential computing units.

© 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Abstract-Metamaterial-enhanced terahertz vibrational spectroscopy for thin film detection

Jingya Xie, Xi Zhu, Xiaofei Zang, Qingqing Cheng, Lin Chen, Yiming Zhu,

Fig. 1 Schematic illustration of (a) the experiment setup, (b) optical image of the metamaterial with L-tartaric acid deposited on it, and (c) the SRR unit cell.

https://www.osapublishing.org/ome/abstract.cfm?uri=ome-8-1-128&origin=search

We present metamaterial-enhanced terahertz vibrational spectroscopy to solve the low sensitivity problem of the THz ray absorption detection in molecular and biomolecular thin film. In a proof-of-principle experiment, we demonstrate the system in split ring resonators (SRRs) metamaterial that is strongly coupled to L-tartaric acid molecular under a low-temperature condition. The experimental results show that the extinction ratio of the detected signal can be significantly improved from 1.75 dB to 4.5 dB. The numerical calculations confirm and explain the experimental observations. By detuning the resonance of metamaterial, the behavior of the spectral signal is modified. When the SRRs and molecular vibrational resonance frequencies are closely aligned, a clear mode splitting is observed resulting in a transparency transmission with enhanced extinction ratio. This method shows great potential for application in thin film sensing by detecting molecular vibrations in the lower-energy terahertz region.

© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Abstract-Terahertz integrated device: high-Q silicon dielectric resonators

Jingya Xie, Xi Zhu, Xiaofei Zang, Qingqing Cheng, Lin Chen, and Yiming Zhu

https://www.osapublishing.org/ome/abstract.cfm?uri=ome-8-1-50

We design, fabricate, and characterize the terahertz integrated resonators on the silicon platform. Based on mode analysis and selection, the high-Q feature of resonators made of low-loss high-resistivity Si material is achieved due to the excitation of the whispering gallery mode on waveguide-coupled single-mode racetrack rings and disk cavities. The experimental results demonstrate that the Q-factor can reach up to 2839 at 218.345 GHz, which is significantly improved compared with conventional THz cavities. These high Q-factor integrated resonators can be used as on-chip terahertz ultrasensitive sensors and as terahertz functional integrated circuits.

© 2017 Optical Society of America under the terms of the OSA Open Access Publishing Agreement