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Optical parametric oscillator for frequency comb generation in the mid-IR

English title Optical parametric oscillator for frequency comb generation in the mid-IR
Applicant Kippenberg Tobias Jan
Number 133830
Funding scheme R'EQUIP
Research institution Laboratoire de photonique et mesures quantiques EPFL - STI - IEL - LPQM2
Institution of higher education EPF Lausanne - EPFL
Main discipline Particle Physics
Start/End 01.08.2011 - 31.07.2012
Approved amount 90'000.00
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Lay Summary (English)

Lead
Lay summary

The mid-infrared spectral range (wavelength ~ micron to 20 micron) is known as the "molecular fingerprint" region as many molecules have their highly characteristic, fundamental ro-vibrational bands in this part of the electromagnetic spectrum. Broadband mid-infrared spectroscopy therefore constitutes a powerful and ubiquitous tool for optical analysis of chemical components that is used in biochemistry, astronomy, pharmaceutical monitoring and material science. Optical frequency combs, i.e. broad spectral bandwidth coherent light sources consisting of equally spaced sharp lines, have revolutionized optical frequency metrology one decade ago. They now demonstrate dramatically improved acquisition rates, resolution and sensitivity for molecular spectroscopy mostly in the visible and near-infrared ranges. Mid-infrared frequency combs have therefore become highly desirable and recent progress in generating such combs by nonlinear frequency conversion has opened access to this spectral region. 

Within this project we plan to use an mid IR CW laser (in the form of the requested OPO of this R'Equip) and demonstrate a promising alternative to mid-infrared frequency comb generation with a continuous-wave pumped ultra-high Q crystalline microresonator made of magnesium fluoride. This would constitute the first mid IR comb generated using the novel Kerr frequency comb technique. Its distinguishing features are compactness, efficient conversion, large mode spacing and high power per comb line. This work therefore opens the path to a versatile mid-infrared spectrometer, and holds promise to facilitate dual-comb spectroscopy. Equally important, combining the broad transparency window (up to 7 micron) of crystalline magnesium fluoride microresonators with high power quantum cascade lasers, a compact frequency comb source that extends deep into the mid-infrared can be envisioned. 

Specifically this proposal seeks to extend microresonator based optical frequency comb technique into the mid-infrared region. The objective of this proposal is to make use of a newly developed technology of the laboratory of ultra-high Q crystalline resonators. These resonators – with transparency window in the mid IR - have not only the highest optical Q factor to date (>10 billion) but moreover are also capable of generating optical frequency combs via parametric frequency conversion. These resonators have so far only been demonstrated by one group at the JPL in Pasadena. Recent work in the applicants group has reproduced these results and made these resonators now also available for studies regarding optical frequency comb generation. Crystalline resonators from the Fluorides offer a unique playground in this context, since they are transparent into the mid IR (i.e. up to ca.8 micron a Q-factor of >100 million can be maintained). Moreover, by tailoring their geometric properties such as diameter, the zero dispersion region can be moved to 2.5 micron wavelength; this opens directly the intriguing opportunity to generate octave spanning comb spectra in the mid-IR from a CW laser source. Having a comb in the mid-IR would allow using techniques such as multi-heterodyne spectroscopy; in particular since the technique could be readily used to demonstrate the required pair of frequency combs. So far, combs in the mid IR have only been generated using difference frequency generation. This technique however cannot produce octave spanning combs and it suffers moreover from low power per comb component. A promising, but to date never verified new approach, could therefore be taken by pumping crystalline resonators with a high power continuous wave laser source, afforded by a CW optical parametric oscillator (Mid IR OPO). It is precisely this OPO that is part of this R'Equip request, which can both be used to pump the crystaline resonators as well as to serve as a narrowband source with which to verify the phase noise.

References:

[1] T. J. Kippenberg, R. Holzwarth, and S. A. Diddams, Science 332, 555 (2011).




Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Publications

Publication
Mid-Infrared Frequency Combs baed on Crystalline Microresonators
Wang Christine, Mid-Infrared Frequency Combs baed on Crystalline Microresonators, in arXiv.org.

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
5th EPS-QEOD Europhoton Conference 2012 26.08.2012 Stockholm, Sweden
CLEO USA 2012 06.05.2012 San Jose, USA
SPIE Photonics West 21.01.2012 San Francisco, USA
4th ESA Conference on Atomic Clocks in Space 24.11.2011 Bari, Italy
IEEE Photonics 2011 (IPC11) 09.10.2011 Arlington, Virginia, USA
CLEO Europe 2011 20.05.2011 Munich, Germany
EFTF Conference 02.05.2011 San Francisco, USA
CLEO USA 2011 30.04.2011 Baltimore, USA
Workshop in WGM for telecommunications 13.04.2011 Noordwijk, Netherlands
DPG Frühjahrstagung 16.03.2011 Dresden, Germany


Associated projects

Number Title Start Funding scheme
165933 Microresonators based Frequency combs: exploring temporal solitons 01.03.2017 Project funding
161573 Photonic Damascene Fabrication Process for High Q integrated SiN Photonic Circuits 01.04.2016 precoR
150740 Mid Infrared spectral analysis instrumentation 01.12.2013 R'EQUIP
146823 Microresonators based Frequency combs in the visible and infrared 01.04.2013 Project funding

Abstract

The development of optical frequency combs has lead over the past decades to major ad-vancements in the ability to measure optical frequency with unprecedented accuracy. Optical frequency combs are the essential clockworks for optical atomic clocks which have enabled to surpass the Cs primary standard. Moreover, optical frequency combs have lead to advances in broadband molecular spectroscopy laser spectroscopy and have been a pivotal tool for the generation of attosecond laser pulses. Moreover, frequency combs have recently been demonstrated to provide superior calibration to astrophysical spectrometers used in the search for extra-solar planets. Indeed, optical frequency combs have become valuable tools in many studies. Building on the already established research infrastructure in the research group of the applicant- and the discovery of monolithic frequency comb specifically -, this proposal seeks to extend the optical frequency comb technique into the mid-infrared region by the use of optical microresonators. This underlying principle was first discovered by the applicant while working at the MPI of Quantum Optics in Germany. This approach offers significant reduction in size, power consumption, foot-print and moreover enables to operate at previously unattainable repetition rate in the range beyond 10 GHz1. The objective of this proposal is to make use of the newly developed technology of the laboratory regarding ultra-high Q crystalline resonators. These resonators have not only the highest optical Q factor to date (>10 billion) but moreover are also capable of generating optical frequency combs via parametric frequency conversion. These resonators have so far only been pioneered and demonstrated by one group at the JPL in Pasadena. Recent work in the applicants group has reproduced these results and made these resonators now also available for studies regarding optical frequency comb generation. Crystalline resonators from the Fluorides (i.e. MF2 or CaF2) offer a unique playground in this context, since they are transparent into the mid IR (i.e. up to 10 micron). Moreover, by tailoring their size the zero dispersion region can be moved to 2.5 micron wavelength; this opens directly the tantalizing and intriguing opportunity to generate octave spanning comb spectra in the mid-IR from a CW laser source. The distinct advantage of the approach would be that the comb generated in this way would be squarely in the molecular fingerprinting region; for which so far only very few laser sources exist that are amenable to frequency metrology. Moreover, having a comb in the mid-IR would allow using techniques such as multi-heterodyne spectroscopy; in particular since the technique could be readily used to demonstrate the required pair of frequency combs. So far, combs in the mid IR have only been generated using difference frequency generation. This technique however cannot produced octave spanning combs and it suffers moreover from low power per comb component. A promising, but to date never verified new approach, could be taken by pumping crystalline resonators with a CW optical parametric oscillator. If succesfull, it is planned to engage in spectroscopic measurements of trace gases as exemplary demonstration.The applicant is a PATT at EPFL who has obtained his PhD at Caltech and lead an Independent Junior Research Group at the MPI of Quantum Optics for 4 ¾ years (for which he obtained his Habilitation at LMU Munich in Germany). The applicant has made recognized contributions in this time to the field of cavity optomechanics and optical frequency metrology, of which the latter is the core of the present proposal and for which he has received the Helmholtz Price in Metrology in 2009. The purchase of this system is leveraged by the fact that the group has al-ready at their disposal a specialized and unique mid-IR spectrum analyzer (Yokogawa) capable of measuring up to 2.5 micron wavelength.
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