Controlling QCLs for frequency metrology from the infrared to the THz range
Authors: Consolino L., Cappelli F., De Regis M., Campo G., Galli I., Mazzotti D., Cancio P., Borri S., Giusfredi G., Bartalini S., De Natale P.
Autors Affiliation: CNR – Istituo Nazionale di Ottica (INO) Largo E Fermi 6, Florence, Italy
Abstract: The Quantum Cascade Laser is becoming a key tool for plenty of applications, from the IR to the THz range. Progress in nearby areas, such as the development of ultra-low loss crystalline microresonators, optical frequency standards and optical fiber networks for time&frequency dissemination, are paving the way to unprecedented applications in many fields. For the most demanding applications, a thorough control of quantum cascade lasers (QCLs) emission must be achieved. In the last few years, QCLs unique spectral features have been unveiled, while multifrequency, comb-like QCLs have been demonstrated. Ultra-narrow frequency linewidths are necessary for metrological applications, ranging from cold molecules interaction and ultra-high sensitivity spectroscopy to infrared/THz metrology. In our group, we are combining crystalline microresonators, with a combined high quality factor in the infrared and ultra-broadband spectral coverage, with QCLs and other nonlinear highly coherent and frequency referenced sources. Frequency referencing to optical fiber-distributed optical primary standards offers astonishing stability values of 10(-16) @1-sec timescales in laboratory environments but several hundred kilometres far away from the primary clocks. A review will be given of the present status of research in this field, with a view to perspectives and future applications.
KeyWords: Crystalline materials; Frequency standards; Nanoelectronics; Optical fibers; Resonators, Frequency disseminations; Frequency metrology; Laboratory environment; Metrological applications; Micro resonators; Optical fiber networks; Optical frequency standard; Quantum cascade lasers (QCLs), Quantum cascade lasersConnecting to view paper tab on IsiWeb: Click here