Corrective Regridding Techniques for Non-Uniform Sampling in Time Domain Terahertz Spectroscopy

Time domain terahertz spectrometers using optical delay stages inherently suffer from non-uniform sampling positions. We review, simulate, and experimentally test the ability of corrective cubic spline and Shannon regridding algorithms to mitigate the inherent sampling position noise. Simulation and experimental results show that regridding increases the signal to noise ratio within the frequency range of 100 GHz to 2 THz. We apply these techniques to study cyclotron resonance of 2DEGs in AlGaAs/GaAs quantum wells and predict that regridding corrections will become increasingly important to both spectroscopy and imaging as THz technology continues to improve.