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.
|Autori:||Consolino L.; Taschin A.; Bartolini P.; Bartalini S.; Cancio P.; Tredicucci A.; Beere H. E.; Ritchie D. A.; Torre R.; Vitiello M. S.; De Natale P.|
|Titolo:||Phase-locking to a free-space terahertz comb for metrological-grade terahertz lasers|
|Anno del prodotto:||2012|
|Digital Object Identifier (DOI):||10.1038/ncomms2048|
|Appare nelle tipologie:||1.1 Articolo in rivista|