Piezo-orbital backaction force in a rare-earth-doped crystal

Hybrid optomechanics can bridge the quantum and classical domains, to generally extend quantum principles to macroscopic scale. A milestone here would be observing the fundamental backaction force that occurs when a hybrid mechanical system is optically probed, which can be dominated by classical thermal effects. Using a large ensemble of rare-earth ions in a crystal plus time-resolved tomography, researchers see this backaction as a tiny distortion of the crystal's surface around a laser beam's spot, and unambiguously distinguish the photothermal contribution from that of the backaction. Thus rare-earth ions in crystals are confirmed as a promising platform for hybrid optomechanics.