Project Title: A Compact System for Terahertz Imaging and Spectroscopy


According to the World Health Organization, an estimated 600 million people fall ill after consuming contaminated food, resulting in 420,000 deaths every year. Closer to home, much of Greater China has been plagued by food-safety fears due to the adulterated baby milk formula in mainland China a few years ago and the recent gutter oil scandal in Taiwan. Spate of tainted drugs containing industrial grade magnesium carbonate also rocked Taiwan in 2015. The agglomeration of food safety, nutrition, and food and drug security will put a strain on our healthcare system and impede our socioeconomic development.

Terahertz (THz) wave is in the electromagnetic spectrum between the conventional microwave and infrared regions with a wide range of applications. It is very sensitive to water molecules and capable of distinguishing intrinsic contrast between normal and cancerous tissues. THz spectroscopy can also differentiate plant oils and animal fats because their refractive indices and absorption rates vary differently with increasing frequency and temperature. THz technologies have also been used in the detection of melamine in milk powder, antibiotics in food matrices, pesticides in vegetables, and foreign objects in drugs and chocolates.

Researchers hoping to exploit this promising frequency regime must confront the enormous entry barriers, attributed to the cost of the testing equipment as well as the availability of THz sources with sufficient power. A low-cost, compact THz system for imaging and spectroscopy not only can accelerate THz research but also resolve more burning issues affecting our welfare. We have assembled an international, multidisciplinary team to develop highly-efficient THz sources and detectors, fast beam scanning devices for data acquisition, signal processing and imagery display for the proposed compact system. On the other hand, research on biomedical imaging, chemical spectroscopy, and imagery display could be simultaneously carried out using existing and currently built THz systems in our laboratory while the compact system is being developed. Our synergistic effort will bring advances in high-resolution biomedical imaging, inspection of materials for high value-added manufacturing and food safety, and will contribute to economies not only in Hong Kong but also Greater China and the rest of the world.

On completion of the project, our expected deliverables are:

Main Points

  1. Terahertz (THz) band lies between the microwave and infrared in the electromagnetic spectrum
  2. THz is non-ionizing, it is safer than ionizing radiation such as X-ray
  3. THz spectroscopy can detect contaminants in foods and drugs
  4. THz radiation is very sensitive to water molecules and can be applied to detect cancerous cells
  5. Current THz equipment is bulky and expensive
  6. We have assembled a team of electronic engineers, materials scientists, biologists and chemists to conduct synergistic and innovative THz research
  7. Our goal is to drive down the cost, compact the size and enhance the performance of THz system for imaging and spectroscopy