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Broadband terahertz comb with sub-Hz comb linewidth
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DOI:10.1117/1.AP.8.2.026015.png)
Abstract
En 中文
Terahertz (THz) frequency combs are increasingly essential for spectroscopy, metrology, and quantum science. However, generating a dense array of evenly spaced ultra-narrow THz comb lines is challenging. Here, we demonstrate broadband THz comb generation using a photoconductive antenna that transfers a noise-suppressed near-infrared electro-optical (EO) comb into the THz domain. Our noise-suppression strategy, leveraging soliton self-frequency shift and spectral filtering, effectively suppresses EO comb phase noise without requiring active stabilization. The resulting THz comb exhibits broad spectral coverage (0.05 to 4 THz), narrow comb linewidths (0.3 Hz at the Fourier-transform limit), and excellent frequency stability (8.6 & times;10(-14) at 1-s integration). We further demonstrate asynchronous THz time-domain spectroscopy, resolving similar to 36,000 comb lines with 50 MHz spacing. Crucially, the inherent frequency agility of the EO comb enables rapid and wide-range tuning of the THz comb line spacing. These attributes position our THz comb as a versatile tool for high-resolution molecular spectroscopy and precision THz metrology.
Keywords:
terahertz comb
electro-optic modulation
frequency stability
comb linewidth
frequency agility
Journal
IF:
18.8
Papers:
961
Citations:
3.6K
