Decade-Spanning High-Precision Terahertz Frequency Comb
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.
© 2015 American Physical Society. Received 28 January 2015. The authors acknowledge the generosity of Professor Jun Ye and his group for loaning amplifiers and for many useful discussions, an anonymous referee for helpful comments, and the National Science Foundation (Grants No. CHE-1214123 and No. CHE-0722330 and the Graduate Research Fellowship Program) for financial support.
Published - PhysRevLett.114.163902.pdf
Supplemental Material - Supplementary_Material.pdf