Real-Time Determination of Absolute Frequency in Continuous-Wave Terahertz Radiation with a Photocarrier Terahertz Frequency Comb Induced by an Unstabilized Femtosecond Laser |
| |
Authors: | Takeo Minamikawa Kenta Hayashi Tatsuya Mizuguchi Yi-Da Hsieh Dahi Ghareab Abdelsalam Yasuhiro Mizutani Hirotsugu Yamamoto Tetsuo Iwata Takeshi Yasui |
| |
Affiliation: | 1.Institute of Technology and Science,Tokushima University,Tokushima,Japan;2.JST, ERATO, MINOSHIMA Intelligent Optical Synthesizer Project,Tokushima,Japan;3.Graduate School of Engineering,Osaka University,Suita,Japan;4.Center for Optical Research and Education,Utsunomiya University,Utsunomiya,Japan |
| |
Abstract: | A practical method for the absolute frequency measurement of continuous-wave terahertz (CW-THz) radiation uses a photocarrier terahertz frequency comb (PC-THz comb) because of its ability to realize real-time, precise measurement without the need for cryogenic cooling. However, the requirement for precise stabilization of the repetition frequency (f rep) and/or use of dual femtosecond lasers hinders its practical use. In this article, based on the fact that an equal interval between PC-THz comb modes is always maintained regardless of the fluctuation in f rep, the PC-THz comb induced by an unstabilized laser was used to determine the absolute frequency f THz of CW-THz radiation. Using an f rep-free-running PC-THz comb, the f THz of the frequency-fixed or frequency-fluctuated active frequency multiplier chain CW-THz source was determined at a measurement rate of 10 Hz with a relative accuracy of 8.2?×?10?13 and a relative precision of 8.8?×?10?12 to a rubidium frequency standard. Furthermore, f THz was correctly determined even when fluctuating over a range of 20 GHz. The proposed method enables the use of any commercial femtosecond laser for the absolute frequency measurement of CW-THz radiation. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|