THz Sensing

Background

Ubiquitous sensing of the world and our environment—including materials, chemical, and medical sensing—is essential not only for enhancing our understanding of ourselves and society but also for preventing severe conditions, such as pandemics, while continuously improving quality of life and advancing societal development. To achieve widespread deployment across diverse scenarios and environments, ubiquitous sensing must exhibit not only high performance—delivering accurate, robust, and trustworthy results—but also fast response times, compact form factors, low cost, and minimal power consumption. Among various sensing approaches, label-free sensing has garnered significant and sustained interest due to its potential in applications such as low-cost point-of-care (POC) diagnostics, biomedical sensing, chemical and material analysis, and advancements in food and agriculture. Label-free sensing primarily falls into two categories: optical sensing and electronic sensing. Optical sensing has been an active research area for decades, offering high resolution due to small wavelengths and low-loss components. However, its reliance on expensive and bulky optical signal sources, highly sensitive detectors, and sophisticated equipment limits its use to specialized facilities. In contrast, electronic sensing has gained increasing attention over the past decade, benefiting from integrated circuit (IC) and system-level on-chip signal processing capabilities. Despite these advantages, electronic sensing suffers from significantly lower resolution—often orders of magnitude poorer than that of optical sensing.

Our Approach

To bridge the critical gap between optical sensing and electronic sensing and develop ubiquitous dielectric sensors that meet the requirements for everyday applications, we are dedicated to advancing terahertz (THz) sensing. Our approach leverages the combined advantages of high-performance quasi-optical sensors, such as micro-ring resonators, and the unparalleled on-chip signal processing capabilities enabled by THz-speed semiconductor devices in modern integrated circuits and systems. This integration allows us to harness the strengths of both optical and electronic sensing while overcoming their respective limitations, paving the way for highly efficient, scalable, and practical sensing solutions.

THz sensing offers several key advantages that make it a compelling choice for next-generation ubiquitous sensing technologies:

  • Ultra-High Sensitivity – By intensifying the evanescent field, THz sensing enhances wave-matter interactions, leading to significantly stronger signal responses. Additionally, high-Q quasi-optical sensing devices, such as micro-ring resonators, further amplify sensitivity, enabling the detection of minute changes in target substances.
  • Superior Resolution – Our holistic noise suppression scheme minimizes external disturbances and system noise, thereby achieving unprecedented sensing resolution. This ensures precise and reliable measurements even in complex and dynamic environments.
  • Compact Form Factor, Low Cost, and Low Power Consumption – THz sensing benefits from the scalability of mainstream semiconductor fabrication processes, which provide cost-effective, miniaturized, and energy-efficient sensor solutions. These characteristics enable wide deployment and accessibility, making THz sensors suitable for a broad range of real-world applications.
  • Trustworthy, Reliable, and Fast Sensing – The integrated THz sensing platform incorporates powerful on-chip signal processing and closed-loop control mechanisms, ensuring resilience against environmental variations and external perturbations. This results in trustworthy, reliable, and high-speed sensing, crucial for applications requiring real-time and accurate detection.

By combining the strengths of optical and electronic sensing within the THz spectrum, we aim to establish a new paradigm in ubiquitous sensing—one that delivers exceptional performance, scalability, and practicality for applications ranging from healthcare and environmental monitoring to industrial automation and consumer electronics.

Publications

  1. H. Yu, X. Ding, J. Chen, S. Sabbaghi and Q. J. Gu, “Design and Analysis of a Sub-THz Resonator-Based High-Resolution Permittivity Sensor,” in IEEE Transactions on Microwave Theory and Techniques, vol. 72, no. 5, pp. 2809-2823, May 2024, doi: 10.1109/TMTT.2024.3357594.
  2. H. Yu, X. Ding, J. Chen, S. S. Saber and Q. J. Gu, “A CMOS 160GHz Integrated Permittivity Sensor with Resolution of 0.05% Δεr,” 2023 IEEE Radio Frequency Integrated Circuits Symposium (RFIC), San Diego, CA, USA, 2023, pp. 245-248, doi: 10.1109/RFIC54547.2023.10186203.
  3. H. Yu, B. Yu, X. Ding, J. S. Gómez-Díaz and Q. J. Gu, “A 162 GHz Ring Resonator based High Resolution Dielectric Sensor,” 2020 IEEE/MTT-S International Microwave Symposium (IMS), Los Angeles, CA, USA, 2020, pp. 233-236, doi: 10.1109/IMS30576.2020.9223997.
  4. B. Yu, X. Ding, H. Yu, Y. Ye, X. Liu and Q. J. Gu, “Ring-Resonator-Based Sub-THz Dielectric Sensor,” in IEEE Microwave and Wireless Components Letters, vol. 28, no. 11, pp. 969-971, Nov. 2018, doi: 10.1109/LMWC.2018.2867092