Spinning Ambulances and Laser Refrigerators: The Rotational Doppler Effect and Optical Cooling of Solids
Dr. Christian Schmiegelow (LIAF Instituto de Física de Buenos Aires)

In this talk, I will address two topics. I will begin by reviewing the interaction between structured light and matter, providing the necessary context to understand one of our most recent experiments, in which we measured the rotational Doppler effect—a Doppler shift that is sensitive to the direction of motion of an object transverse to the probing beam. This elusive effect was predicted several years ago, but until now, there had been no clear experimental confirmation of its existence. Our experiments clearly show that its physical properties, although counterintuitive, are as expected, and they enable the observation of even more exotic phenomena, such as the so-called "super kicks", where a single photon can transfer more momentum to an atom than ℏk.

After that, I will present a new series of experiments aimed at improving current methods for laser cooling of solids. I will explain the principles of anti-Stokes cooling, recent advances, and the perspectives for the coming years.