Metrology Issues and Solutions in THz Time-Domain Spectroscopy: Noise, Errors, Calibration

This paper reviews metrology aspects of terahertz time-domain spectroscopy. Noise is discussed together with its effects on system performance, including frequency-dependent dynamic range, signal-to noise ratio, and the measurement bandwidth. Sources of uncertainties are addressed, as are measurement errors arising from system design and from interactions with the object under test. Finally, techniques of system calibration are described. Commonly encountered issues are addressed and simple practical solutions suggested. Existing literature on the subject is reviewed.