An optical setup comprising an external Fabry-Pérot (FP) cavity that maintains ultrashort pulse spatial and temporal coherence, is proposed to generate continuous sub-terahertz repetition rate ultrashort pulses (USP). Analytical results from different sets of pulse-to-pulse carrier-envelop phase offset ( $\Delta \varphi _{\mathrm {CEO}}$ ) output conditions manifest the possibility to extract and utilize the reflected USP signal from an ultrastable Pound-Drever-Hall phase-locked external FP cavity to stabilize or reset the $\Delta \varphi _{\mathrm {CEO}}$ to 0 or multiple of $2\pi $ rad in real time. The generation of a steady, ultrahigh repetition rate output, from a low repetition rate ultrashort pulse laser requires management of carrier-envelope phase (CEP). The CEP management with the passive external FP cavity group delay dispersion control enables transition from usual quasi- to continuous repetition rate. The net control and management of these parameters allow the passive external FP cavity multiplication factor to be increased above 200.

中文翻译：

---

通过相干外部Fabry-Pérot腔产生连续的THz重复频率CEP稳定的超短激光脉冲

提出了一种光学装置，该装置包括一个可维持超短脉冲空间和时间相干性的外部Fabry-Pérot（FP）腔，可产生连续的太赫兹重复率超短脉冲（USP）。不同组脉冲间载波-包络相位偏移的分析结果（ $ \ Delta \ varphi _ {\ mathrm {CEO}} $ ）输出条件表明有可能从超稳定的Pound-Drever-Hall锁相外部FP腔中提取和利用反射的USP信号来稳定或重置 $ \ Delta \ varphi _ {\ mathrm {CEO}} $ 到0或倍数 $ 2 \ pi $ rad实时。从低重复率的超短脉冲激光器产生稳定的，超高重复率的输出，需要管理载波包络相位（CEP）。通过被动外部FP腔组延迟分散控制进行CEP管理，可以从通常的准重复率过渡到连续重复率。这些参数的净控制和管理使无源外部FP腔倍增系数增加到200以上。