Observation of spurious spectral features in mixed-powder compressed pellets measured by terahertz time-domain spectroscopy.

Spurious loss features were observed in mixed-powder compressed pellets measured in transmission using terahertz time-domain spectroscopy. Loss features were identified in two types of pellets: PTFE-glass microspheres and PTFE-lactose. The features were found to be dependent on particle size and concentration. An explanation is proposed, based on varying optical thickness of the sample material.