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Terahertz Applications Group

Department of Chemical Engineering and Biotechnology

Studying at Cambridge


Measurement Principle

Measurement Principle

Terahertz radiation is unique in that it can penetrate into and through a number of materials, such as polymers, ceramics, and amorphous pharmaceutical excipients. Also many crystalline materials have characteristic spectral features in terahertz range.  Image or chemical data can be extracted from the reflected or transmitted radiation. Recently, terahertz radiation has been used in pharmaceutical applications such as polymorph identification and quantification, phase transition monitoring, and hydrate forms.  

TPI measurement principle: A pulse on THz radiation is focused onto the surface of the coated tablet. At each coating interface a reflection occurs and from the time delay between subsequent reflections the coating thickness can be calculated.