A high-resolution and high-speed terahertz spectrometer based on asynchronous optical sampling

We have developed a terahertz time-domain spectrometer which is characterized by a large bandwidth, a high spectral resolution, and a high sensitivity achieved´ in short data acquisition times. The bandwidth of the spectrometer is larger than 3 THz and the resolution is 1 GHz. A sensitivity of 60 dB dynamic range is achieved in a data acquisition time of less than one minute. The THz spectrometer is based on high-speed asynchronous optical sampling (ASOPS). High-speed ASOPS employs two femtosecond lasers of approx. 1 GHz repetition rate. These lasers are electronically stabilized to 10 kHz off-set frequency of the repetition rates. The two lasers are used for generation and detection of THz pulses in the time-domain without using a mechanically moving part. The high-speed ASOPS THz spectrometer opens new perspectives to perform high-resolution THz spectroscopy.