An etalon-based method for frequency calibration of terahertz time-domain spectrometers (THz TDS)

We present an etalon-based method of calibrating the frequency of terahertz time-domain spectrometers (THz TDS). The method utilizes the etalon effect produced by multiple reflections in non-absorbing wafers or in narrow air–gaps. The technique provides frequency calibration across the measurement band with uncertainties comparable with the typical THz TDS resolution.