Speaker
Description
My PhD project aims to overcome a fundamental limitation in gravitational wave detectors and optical clocks:
coating Brownian thermal noise (CBTN), which arises from microscopic vibrations in mirror coatings. The
proposed solution is to reshape laser beams into exotic optical modes—specifically Hermite-Gaussian (HG)
modes—which distribute light more broadly across mirror surfaces, reducing thermal noise.
The first objective is to demonstrate HG25,25 modes in optical clocks, improving timekeeping precision without
relying on cryogenics or crystalline coatings. HG25,25 has been generated at high purity but never applied in a
clock, making its implementation novel and feasible.
The second objective is to implement HG33 modes in the Einstein Telescope High Frequency (ET-HF)
interferometers, enabling detection of primordial black holes by reducing thermal noise at 30 Hz. HG33 is the
highest-order mode compatible with ET’s current mirror design, making it optimal for near-term upgrades.
The built cavities will also be used to detect displacements of less than a femtometre, taking advantage of the
precision of the best atomic clocks and a frequency comb for increased sensitivity.
This interdisciplinary project bridges optics, metrology, mechatronics, and GW instrumentation, leveraging
collaborations across UCLouvain, NIKHEF, and ULiege. It is timely, as Belgium strengthens its connection to
international timing networks and advances its candidacy to host the Einstein Telescope. The project promises
advances in ultra-precise timekeeping, GW sensitivity, and optical cavity engineering.
