Quality control by THz spectroscopy of animal feeds and a printed polarizer

Abstract

This master's project aims to provide applications of THz spectroscopy in quality control and inspection. The literature review focuses on THz waves and explains the different aspects of THz spectroscopy, with emphasis on food quality control. In addition, to facilitate the understanding of THz spectroscopy and its possibilities for quality control, the use of THz waves is defined in the context of printed electronics (PE) manufacturing. The methodology section includes three different configurations for THz spectroscopy food inspection and sample preparation for this study. To better understand THz reflection spectroscopy, four different samples are studied by reflection simulation. Finally, the functionality of a terahertz (THz) polarizer fabricated using an industrial roller press to print silver nanoparticle ink on polyethylene terephthalate (PET) was investigated by THz time domain spectroscopy. The results confirm the differentiation of the signal between the 0% plastic sample and the sample containing 20% plastic volume.The identification of frequencies that can be used for this type of inspection is quite clear. The frequency range between 0.2 and 0.4 THz seems to be the perfect candidate for probing feed. In addition,the results of the reflection simulation show that wavelet analysis could be a good tool for detecting minor particle features. Finally, looking at the results of the fabricated polarizer, all symmetric degrees support each other, confirming the proper functioning of the polarizer. Further stacking of these inexpensive polarizers demonstrates nearly equivalent performance of commercial polarizers in the 0.1 to 1 THz frequency range.

Date	18 Apr 2022
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	François Blanchard (Supervisor)