In this project a novel measurement method for continuous measurements of the temporal position and amplitude of a terahertz (THz) pulse was developed. The advantage of this approach is a reduced sampling time of ~20ms and an increased resolution of less than 10µm. The method is therefore very well suited for online measurements in production processes to monitor the thickness, interface position and inhomogeneities of the composition in non-conducting materials. (FFG Project Number 838830)
ITIS - Intelligentes THz Interface Scanning
For this project a fast oscillating mirror mounted on a moving coil actuator was integrated into a standard THz time-domain (TD) setup for transmission measurements. This additional delay line was developed in cooperation with i-RED GmbH. The data acquisition and feedback control of the slowly moving mechanical stage was built around a real-time PXIe system from National Instruments.
The temporally modulated signal was analyzed with a lock-in amplifier from Anfatec which can analyze the input signal at the carrier frequency and any harmonic simultaneously. From the 1st harmonic the pulse amplitude can be determined, while the 2nd harmonic is used to monitor the position of the THz pulse.