Giving to CREOL CREOL, The College of Optics & Photonics

Colloquium: "Differential intracavity interferometry with double-frequency combs for high precision sensing" by Dr. Jean-Claude Diels

Monday, November 19, 2018 12:00 PM to 1:00 PM
CREOL Room 103

Jean-Claude Diels, Ph.D.
Department of Physics & Astronomy
Department of Electrical & Computer Engineering
Center for High Technology Materials
The University of New Mexico


Frequency combs are revolutionizing metrology and sensing, providing absolute frequency cali-bration over the optical spectrum, as well as a link between optical and RF frequencies. We achieve extreme sensitivity and low noise in phase detection by using a mode-locked laser as a differential interferometer. Two pulses circulating inside the laser cavity serve as pump and probe [1]. The active laser cavity is more sensitive to minute perturbations than a passive resonator.
A passive interferometer such as a Michelson measures phase differences by converting them into an amplitude modulation. By contrast, in the Intracavity Phase Interferometer, a minute phase shift is converted into a frequency. The improvement in signal to noise is the same as that of FM radio over AM radio.
Two ultrashort pulses are circulating in the laser cavity, producing two interfering frequency combs. The noise in the two output combs is correlated, resulting in a sub-Herz beat note band-width, even when the individual mode of each frequency comb is several MHz wide (typical of an unstabilized laser).
Measurements of phase with a sensitivity of 1:108 has been demonstrated with an un-stabilized laser made of free space components. A new method of phase response ampli?cation is presented, the analogue of the electronic ampli?er with feedback [2]. In this technique, each of the tooth of the frequency combs is locked to a giant dispersion.
This complex laser with two intracavity pulses leads itself to a simple quantum mechanical analogy of two level systems [3]. This analogy may inspire further schemes of sensitivity enhan-cement.


Jean-Claude Diels started his career in Research constructing a CO2 laser as part of his one year military service (too long) in Belgium.  He went then for 5 years (much too long) as a Research Scientist in the fundamental Research laboratories of “Philips Gloelampenfabrik” in Eindhoven, with assignment to “do modern research” with “unlimited budget (which was soon exceeded).  He spent the next 3 years (way too short) to do Ph.D. thesis research on coherent pulse propagation in two level systems with Professor Erwin L. Hahn at UC Berkeley.  The next two years (too long) were spent at the Max Plank Institute with Professor Fritz Schaefer, the colorful (usually covered with red) father of dye lasers.  He got an appointment as Associate Research Professor at the University of Southern California (“What??? I have to raise my own salary?”).  After experiencing the “Centre d’Energie Atomique” of Saclay near Paris (not the Texan Paris),  he moved to the CAQE (Center for Applied Quantum Electronics) of the University of North Texas in Denton, where he stayed for 5 years (too long), interrupted by a sabbatical at the University of Bordeaux, France.  He has been since … (much too long) at the University of New Mexico, where he graduated more than 50 PhD students.  He co-authored with Wolfgang Rudolph the graduate textbook  Ultrashort Laser Pulse Phenomena: Fundamentals, Techniques and Applications on a Femtosecond Time Scale and with Ladan Arrisian the book, Lasers:  The Power and Precision of Light, celebrating the 50th anniversary of the laser, and published 5 book chapters.    He is the recipient of the 51st Annual Research Lecturer Award (April 2006),  and of the 2006 Engineering Excellence Award of the Optical Society of America.

For Additional Information:

Demetrios Christodoulides

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