Abstract-Decade-Spanning High-Precision Terahertz Frequency Comb

Ian A. Finneran, Jacob T. Good, Daniel B. Holland, P. Brandon Carroll, Marco A. Allodi, and Geoffrey A. Blake

Phys. Rev. Lett. 114, 163902 – Published 21 April 2015

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.114.163902

The generation and detection of a decade-spanning terahertz (THz) frequency comb is reported using two Ti:sapphire femtosecond laser oscillators and asynchronous optical sampling THz time-domain spectroscopy. The comb extends from 0.15 to 2.4 THz, with a tooth spacing of 80 MHz, a linewidth of 3.7 kHz, and a fractional precision of 1.8×10−9. With time-domain detection of the comb, we measure three transitions of water vapor at 10 mTorr between 1–2 THz with an average Doppler-limited fractional accuracy of 6.1×10−8. Significant improvements in bandwidth, resolution, and sensitivity are possible with existing technologies.

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