Séminaire

Mercredi 4 Novembre 2026 à 11h00.

Statistical optics in a white box: interferometry, dielectric relaxation spectroscopy & ultrasensitive light detection

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The notion that light travels along straight lines with a well-defined wave vector, at least locally, breaks down in strongly scattering random media. We recently designed an extremely white cavity, which produces a “perfect” 3D random wave in free space. It is best described by as photon gas with a uniform density and a wave vector being a random field with spherically symmetric statistics. Using this unique field geometry which we refer to as 3D Berry field with feedback control, we developed coherent methods: random volume interferometry, amplified diffusing wave spectroscopy (A-DWS), and low-frequency dielectric spectroscopy. We also developed an incoherent application, namely the ultra-sensitive detection of luminescence. I will describe experimental results on ultra-weak luminescence and random interferometry, and introduce our elementary theory for the interferometric response of the 3D Berry field. Finally I will discuss the analogy with thermal light, the issue abnormal photon statistics, and the arbitrarily strong super-linearity.

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