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Volume 42, Issue 9
Special Issue on Developments of the Optical Frequency Comb
Displaying 1-7 of 7 articles from this issue
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Special Issue on Developments of the Optical Frequency Comb
Special Issue
Laser Review
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Hajime INABA2014 Volume 42 Issue 9 Pages 694-
Published: 2014
Released on J-STAGE: September 07, 2020
JOURNAL OPEN ACCESSDownload PDF (181K) -
Takuro IDEGUCHI2014 Volume 42 Issue 9 Pages 695-
Published: 2014
Released on J-STAGE: September 07, 2020
JOURNAL OPEN ACCESSLaser frequency comb has recently been utilized in a variety of fields beyond its original application for the precision spectroscopy. Here, we introduce another application for broadband molecular spectroscopy. Dual-comb spectroscopy has surpassed the capabilities of conventional Fourier transform spectroscopy based on a Michelson interferometer in terms of measurement speed, spectral resolution, and accuracy. In this review paper, basics of the dual-comb spectroscopy and hot topics in this field are discussed.View full abstractDownload PDF (504K) -
Takeshi YASUI, Yi-Da HSIEH2014 Volume 42 Issue 9 Pages 700-
Published: 2014
Released on J-STAGE: September 07, 2020
JOURNAL OPEN ACCESSWe demonstrated combination of gapless terahertz (THz) comb with asynchronous-optical-sampling THz time-domain spectroscopy (ASOPS-THz-TDS), namely gapless THz comb spectroscopy. The mode-resolved spectrum of THz comb was observed by measuring the temporal waveform of the THz pulse train with ASOPS-THz-TDS and calculating Fourier transform of it. Furthermore, the gapless THz comb was realized by interpolating frequency gaps between the comb modes with sweeping of a laser mode-locked frequency. The demonstration of low-pressure gas spectroscopy with gapless THz comb spectroscopy clearly indicated that the spectral resolution was decreased down to 2.5-MHz linewidth of the comb mode and the spectral accuracy was enhanced to 10‒7 within the spectral range of 1 THz. The proposed method will be a powerful tool to simultaneously achieve high resolution, high accuracy, and broad spectral coverage in THz spectroscopy.View full abstractDownload PDF (1132K) -
Takashi KUROKAWA, Ken KASHIWAGI, Takayuki KOTANI, Jun NISHIKAWA, Motoh ...2014 Volume 42 Issue 9 Pages 706-
Published: 2014
Released on J-STAGE: September 07, 2020
JOURNAL OPEN ACCESSIn order to discover Earth-like exoplanets, we need a Doppler shift detection capability with high accuracy of 0.7 MHz in the near-infrared region. A broadband laser frequency comb (LFC) has been greatly expected as ideal standards for the calibration of astronomical spectrographs. The requirements for the LFC are broad bandwidth, high frequency stability and multi-gigahertz spacing spectrally resolvable by the spectrographs. In order for the Subaru telescope to challenge the Earth-like exoplanet detection, we have developed the LFC generator consisting of an optical pulse synthesizer, an optical pulse compressor and a highly nonlinear fiber. The two stage amplification having band-pass filters and a Fabry-Perot filter realized high power pump pulses with low noise. We successfully generated the 12.5-GHz-spacing laser frequency comb ranging over 600 nm from 1070 to 1700 nm.View full abstractDownload PDF (693K) -
Shigeo NAGANO, Hiroyuki ITO, Motohiro KUMAGAI, Masatoshi KAJITA, Yuko ...2014 Volume 42 Issue 9 Pages 711-
Published: 2014
Released on J-STAGE: September 07, 2020
JOURNAL OPEN ACCESSAbsolute frequency measurement system in THz region is an indispensable tool for the establishment of THz frequency standard. We have developed a THz frequency counter based on THz comb using a photoconductive antenna with a femtosecond-pulse fiber laser. The THz counter has the fractional frequency uncertainty of 1.7 × 10‒17 at 0.3 THz and an instability of 4.1 × 10‒14/τ up to an averaging time of 104s.View full abstractDownload PDF (615K) -
Kazuhiro IMAI, Motonobu KOUROGI, Souichi TERADA2014 Volume 42 Issue 9 Pages 716-
Published: 2014
Released on J-STAGE: September 07, 2020
JOURNAL OPEN ACCESSUsing two electro-optic modulator-based optical frequency comb sources, we demonstrate an optical frequency comb interferometer that enables rapid and precise measurement of over long distances. 500 kHz is the repetition rate of the relative measurement of a 6-mm ambiguity range. The repetition rate of an absolute distance measurement is about 15 Hz with switching modulation frequencies. The optical frequency comb interferometer yields 0.4-μm precision at 5.2 m in 2 μs. The improved precision exceeded 30 nm in 1 ms.View full abstractDownload PDF (678K) -
Tatsutoshi SHIODA2014 Volume 42 Issue 9 Pages 722-
Published: 2014
Released on J-STAGE: September 07, 2020
JOURNAL OPEN ACCESSWe proposed an ultrafast optical arbitrary waveform synthesizer and analyzer in the femtosecond and picosecond time regions. Ultrafast waveforms were generated by manipulating the amplitude and the phase of a 200-GHz optical frequency comb (OFC) using a customized colorless optical synthesizer. The synthesized waveform was then analyzed on the frequency axis using a custom heterodyne-detection technique based on dual-heterodyne mixing. With our proposed system, we generated femtosecond pulses and synthesized composite amplitude-shift and phase-shift keying signals of 22.4-Tbit/s with 112-bit packets in data processing.View full abstractDownload PDF (1782K)
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