Terahertz imaging has a wide range of applications in the field of nondestructive testing. In this paper, a novel thickness-testing method based on active terahertz imaging with a non-cooled focal plane array terahertz camera is proposed, which uses the poly tetra fluoroethylene (PTFE) as the object to study. Firstly, we capture the active terahertz images of PTFE wafers of different thickness using IRXCAM-THz-384 camera. Second, by using the curve fitting method, interpolation method, grey theory model, neural network and support vector machine, the relationship between the thickness of PTFE wafers and grayscale is predicted. Then the accuracy of different methods is compared. Finally, we establish the thickness-grayscale relationship model. The experimental results show that the predicted greyscale data is close to the actual data, and the error range can be controlled within 1%, which verifies the accuracy of the model and meets practical engineering application standards.
High-speed Terahertz Time domain spectroscopy (High-speed THz-TDS) system is developed on the basis of traditional THz-TDS. It can effectively compensate for the shortcomings of traditional THz-TDS. High-speed THZ-TDS features fast spectrum scanning speed and High spectrum resolution. But it needs a stable local clock signal to lock the repetition rate of the laser in the system. In this paper, a method of taming OCXO with China's BeiDou Navigation Satellite System (BDS) is proposed to generate stable clock signals. Using this signal as the local clock for the high-speed THZ-TDS. The cost of this method is 2,600 yuan, less than one-tenth of the price of rubidium atomic clocks, without significantly reducing stability. This method provides a high stability, low cost clock signal for high-speed THZ-TDS system, and has long term stability.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.