Non-destructive sub-THz CW imaging

Nicholas Karpowicz, Hua Zhong, Jingzhou Xu, Kuang-I Lin, Jenn Shyong Hwang, Xi Cheng Zhang

Research output: Contribution to journalConference articlepeer-review

35 Citations (Scopus)


A simple, compact CW sub-THz imaging system, utilizing a 0.2 and 0.6 THz Gunn diode source is presented. A silicon beam lead diode detector and a Golay cell are used for the detection. Various results are presented, which show that the CW THz imaging modality is suitable for diverse applications, such as non-destructive testing and security. The key components of the system include the Gunn diode assembly, an optical chopper, a polyethylene lens, a detector, a lock-in amplifier, and two translation stages. The beam from the Gunn diode is focused on the sample being imaged by the polyethylene lens, the transmitted or reflected beam is measured by the detector. The energy transmitted through the sample at each point in the plane of the sample is detected. Since the system has relatively few components compared to pulsed THz imaging systems, it is less expensive and easier to design and operate, although it does not provide depth or spectral information about the sample. Since no time-delay scans take place, scanning can be done quickly compared to a time-domain system, limited by the maximum velocity of the translation stages and response of the detectors. It provides information about the macroscopic features of hidden structures within materials that are transparent to sub THz radiation, such as space shuttle insulating foam, articles of clothing, and luggage.

Original languageEnglish
Article number21
Pages (from-to)132-142
Number of pages11
JournalProceedings of SPIE - The International Society for Optical Engineering
Publication statusPublished - 2005 Jul 21
EventTerahertz and Gigahertz Electronics and Photonics IV - San Jose, CA, United States
Duration: 2005 Jan 232005 Jan 25

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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