Incorporating a Fast Scan Unit Into Terahertz Spectroscopy

Time-domain terahertz spectroscopy is one of the best methods for studying materials in the terahertz frequency range. In terahertz spectroscopy, a process known as scanning is used to trace out the time dependence of the terahertz pulse. If these scans are made rapidly (100 ms) and many fast scans are averaged together, the impact of low frequency laser noise should be lower than if a single slow scan is performed over the same time period (2 minutes). A fast scan unit, the ODL-150 Scanning Optical Delay Line, made by Clark-MX Inc. was incorporated into the existing spectrometer to test this prediction. Precise positioning of the fast scan unit was of utmost importance, as any laser shifting, caused by a misalignment of the laser beam and the scanning track, would skew the data. Testing has shown that data taken using the new fast scan unit has lower noise than data taken with the slow scan unit.