Department of Physics & Astronomy
University of New Mexico

Physics and Astronomy Colloquium

Optical Frequency Combs and Quantum Metrology

Presented by Dr. Scott Diddams (UC Boulder)

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 no 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 with the goal of defining the standard quantum limit for metrology with optical frequency combs. Highlights will be provided for measurement scenarios that impact applications in clocks, climate and health diagnostics and exoplanet searches. Moreover, I will discuss the prospects of frequency comb interferometry with non-classical states of light and electric-field-correlation spectroscopy of thermal light that could form a critical component of future long baseline interferometry in the mid and near-infrared.

3:30 pm, Friday, March 8, 2024


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