Lecture: Optical Frequency Combs: From Classical to Quantum
Join Professor Scott Diddams for a lecture on the quantum applications of optical frequency combs.
Date: Monday 15 December 2025
Time:
- 10:30 am – 11:15 am: Presentation
- 11:15 am – 11:30 am: Q&A
- 11:30 am – 12:00 pm: Morning tea with cake, coffee and tea
Location: Building 80, RMIT University (see on a map)
Registered attendees will be emailed the specific room number closer to the date.
Presentation abstract
The optical frequency comb is one of the most significant advances in laser physics since the development of the laser itself. It has made routine the counting and synthesis of the oscillations of light on the femtosecond time scale, and it is an essential component of all present and future optical clocks and time-transfer systems.
It further enables the most accurate measurement of any fundamental physical quantity—that of the quantized energy states of atoms and ions with 18 digits of precision.
Despite this close connection to quantum systems, there are few demonstrations of how an optical frequency comb could yield a quantum advantage for metrology. The most important limitation remains in photodetection, where shot noise sets the fundamental signal-to-noise ratio.
However, there are important and impactful differences in the detection of frequency comb light that yield surprising results, with time-stationary shot-noise limits being surpassed.
We are exploring these limits and seeking improvements that will impact the most precise clocks, as well as frequency comb interferometry with non-classical states of light and new electric-field-correlation spectroscopy of thermal light that could form a critical component of future long baseline optical interferometry.
About Professor Scott Diddams
Scott Diddams holds the Robert H. Davis Endowed Chair at the University of Colorado Boulder, where he is also Professor of Electrical Engineering and Physics. He carries out experimental research in the fields of precision spectroscopy and quantum metrology, nonlinear optics, microwave photonics and ultrafast lasers.
Diddams received the Ph.D. degree from the University of New Mexico in 1996. From 1996 through 2000, he did postdoctoral work at JILA, NIST and the University of Colorado. Subsequently, Diddams was a Research Physicist, Group Leader, and Fellow at NIST (the National Institute of Standards and Technology).
In 2022 he transitioned to his present position where he also assumed the role of Faculty Director of the Quantum Engineering Initiative in the College of Engineering and Applied Science.
As a postdoc Diddams built the first optical frequency combs in the lab of Nobel laureate John Hall, and throughout his career, he has pioneered the use of these powerful tools for optical clocks, tests of fundamental physics, novel spectroscopy, and astronomy.
His research has been documented in more than 750 peer-reviewed publications, conference papers, and invited talks. The work of Dr. Diddams and his research group has been recognized by multiple awards. These include the Distinguished Presidential Rank Award, the Department of Commerce Gold and Silver Medals for “revolutionizing the way frequency is measured”, as well as the Presidential Early Career Award in Science and Engineering (PECASE), the C.E.K. Mees Medal from OPTICA (formerly OSA), the IEEE Photonics Society Laser Instrumentation Award, and the IEEE Rabi award.
He is a Fellow of OPTICA, IEEE and the American Physical Society.