Korean Journal of Optics and Photonics (한국광학회지)

Optical Society of Korea (한국광학회)
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High-Speed High-Resolution Terahertz Time-Domain Spectrometer

고속 고분해 테라헤르츠 시간영역 분광기

  • Kim, Young-Chan (Safety Metrology Center, Korea Research Institute of Standards and Science) ;
  • Kim, Ki-Bok (Safety Metrology Center, Korea Research Institute of Standards and Science) ;
  • Yee, Dae-Su (Safety Metrology Center, Korea Research Institute of Standards and Science) ;
  • Yi, Min-Woo (Dept. of Physics, Korea Advanced Institute of Science & Technology) ;
  • Ahn, Jae-Wook (Dept. of Physics, Korea Advanced Institute of Science & Technology)
  • 김영찬 (한국표준과학연구원 안전계측연구단) ;
  • 김기복 (한국표준과학연구원 안전계측연구단) ;
  • 이대수 (한국표준과학연구원 안전계측연구단) ;
  • 이민우 (한국과학기술원 물리학과) ;
  • 안재욱 (한국과학기술원 물리학과)
  • Published : 2008.10.25
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Abstract

High-speed high-resolution terahertz time-domain spectroscopy (THz-TDS) is demonstrated using the asynchronous-opticalsampling (AOS) method. A time-domain signal with a 10-ns time window is rapidly acquired by using two femtosecond lasers with slightly different repetition frequencies to generate and detect a terahertz pulse wave, without a mechanical delay stage. The spectrum obtained by the fast Fourier transformation (FFT) of the time-domain waveform has a frequency resolution of 100 MHz. The time resolution of our spectrometer is measured using the cross-correlation method to be 278 fs. A transmission spectrum of water vapor is measured and the absorption lines are analyzed in the frequency range from 0.1 to 1.2 THz.

본 논문에서 비동시성 광샘플링(asynchronous optical sampling; AOS) 방식을 이용하는 고속 고분해 테라헤르츠 시간영역 분광(terahertz time domain spectroscopy; THz-TDS)을 시연한다. 모터로 구동되는 선형 스테이지를 사용하지 않고, 약간 다른 반복 주파수를 갖는 두 대의 펨토초 레이저를 각각 테라헤르츠파 발생과 검출에 사용하여 고속으로 10 ns의 시간축 상의 신호를 획득하고 fast Fourier transformation(FFT)을 통하여 100 MHz의 주파수 분해능을 갖는 고분해 분광을 구현한다. Cross-correlation 방법에 의해 시간 분해능은 278 fs으로 측정되었다. 또한, 본 분광기를 이용하여 수증기의 투과 스펙트럼을 측정하고 흡수선들을 분석하였다.

Keywords

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