Triggerless data acquisition in asynchronous optical-sampling terahertz time-domain spectroscopy based on a dual-comb system
Triggerless data acquisition in asynchronous optical-sampling terahertz time-domain spectroscopy based on a dual-comb system
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DOI：
10.1364/oe.472192
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发表时间：
2022-10-24
期刊：
影响因子：
3.8
通讯作者：
Watanabe, Shinichi
中科院分区：
文献类型：
--
作者：
Okano, Makoto;Watanabe, Shinichi
利用两个重复频率略有不同的锁相光频梳，在不使用任何触发信号或光延迟线的情况下，实现了异步光采样太赫兹时域光谱（ASOPS THz-TDS）.由于重复频率的严格稳定性，可以以无干扰的方式积累48分钟以上的数据而不会降低信号。测量的太赫兹信号的分数频率稳定性被评估为在730 s后类似于8.0 x 10-17。通过将两个频率梳锁相到频率标准来确保所获得的太赫兹频谱的频率精度。为了阐明我们的系统的性能，我们表征了水蒸气在0.557 THz附近的吸收线。测量的中心频率和线宽与HITRAN数据库预测值的良好一致性验证了我们的ASOPS THz-TDS系统用于精确测量的适用性。(c)2022 Optica出版集团根据Optica开放获取出版协议的条款
By using two mutually phase-locked optical frequency combs with slightly different repetition rates, we demonstrate asynchronous optical-sampling terahertz time-domain spec-troscopy (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 similar to 8.0 x 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.(c) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement