Influence of the Precision of Time Delay on Terahertz Time Domain Spectroscopy

Abstract

The influence in which the precision of time delay gives the spectrum on terahertz time domain spectroscopy is reported. The precision of time delay is proportional to the positional accuracy of the motorized translation stage which gives time delay. The experimental result confirms that positional error of the stage increases the spectral noise and it also lowers the repeatability of the spectrum. The positional accuracy of the stage affects the higher frequency region of the spectrum greatly. Those indicate that the positional accuracy is an important parameter to show the reliability of terahertz time domain spectroscopy. The evaluation of the influence of the positional accuracy of the stage on the spectrum by computer simulation is suggested. The method to lower the spectral noise and to improve in the repeatability of the spectrum by measuring the positional error with the signal waveform simultaneously and correcting the signal waveform is proposed. It is shown by an experiment as well as computer simulation that this method is effective.