• DOI:10.1038/ncomms2048
• Corpus ID: 205313805

Phase-locking to a free-space terahertz comb for metrological-grade terahertz lasers

@article{Consolino2012PhaselockingTA,
  title={Phase-locking to a free-space terahertz comb for metrological-grade terahertz lasers},
  author={Luigi Consolino and Andrea Taschin and Paolo Bartolini and Saverio Bartalini and Pablo Cancio and Alessandro Tredicucci and Harvey E. Beere and David A. Ritchie and Renato Torre and Miriam Serena Vitiello and Paolo De Natale},
  journal={Nature Communications},
  year={2012},
  volume={3}
}

• L. Consolino, A. Taschin, +8 authors P. De Natale
• Published 1 January 2012
• Physics
• Nature Communications

Optical frequency comb synthesizers have represented a revolutionary approach to frequency metrology, providing a grid of frequency references for any laser emitting within their spectral coverage. Extending the metrological features of optical frequency comb synthesizers to the terahertz domain would be a major breakthrough, due to the widespread range of accessible strategic applications and the availability of stable, high-power and widely tunable sources such as quantum cascade lasers. Here we demonstrate phase-locking of a 2.5 THz quantum cascade laser to a free-space comb, generated in a LiNbO3 waveguide and covering the 0.1–6 THz frequency range. We show that even a small fraction (<100 nW) of the radiation emitted from the quantum cascade laser is sufficient to generate a beat note suitable for phase-locking to the comb, paving the way to novel metrological-grade terahertz applications, including high-resolution spectroscopy, manipulation of cold molecules, astronomy and telecommunications. Frequency comb synthesizers are important for metrology, but they have been difficult to use as frequency rulers in the terahertz region due to their low power. Consolinoet al. phase-lock a quantum cascade laser to a free-space-propagating terahertz comb, demonstrating that they can overcome this limitation.