Triggerless data acquisition in asynchronous optical-sampling terahertz time-domain spectroscopy based on dual-comb system

Abstract

By using two mutually phase-locked optical frequency combs with slightly different repetition rates, we demonstrate asynchronous optical-sampling terahertz time-domain spectroscopy (ASOPS THz-TDS) without using any trigger signals or optical delay lines. Due to a tight stabilization of the repetition frequencies, it was possible to accumulate the data over 48 minutes in a triggerless manner without signal degradation. The fractional frequency stability of the measured terahertz signal is evaluated to be $\sim$8.0$\times$10${}^{-17}$ after 730 s. The frequency accuracy of the obtained terahertz spectrum is ensured by phase-locking the two frequency combs to a frequency standard. To clarify the performance of our system, we characterized the absorption line of water vapor around 0.557 THz. The good agreement of the measured center frequency and linewidth with the values predicted from the HITRAN database verifies the suitability of our ASOPS THz-TDS system for precise measurements.

References in corpus (4)

• Coherent Dual Comb Spectroscopy at High Signal to Noise
• Terahertz wave generation using a soliton microcomb
• Adaptive sampling dual terahertz comb spectroscopy using free-running dual femtosecond lasers
• Dual terahertz comb spectroscopy with a single free-running fibre laser

Cited by in corpus (3)

• A two-color dual-comb system for time-resolved measurements of ultrafast magnetization dynamics using triggerless asynchronous optical sampling
• Jitter correction for asynchronous optical sampling terahertz spectroscopy using free-running pulsed lasers
• Robust asynchronous optical sampling terahertz spectroscopy using commercially available free-running lasers