Henry Reich from Minute Physics explains the science behind Serge Haroche's quantum non-demolition measurements. Since Max Planck and his study of black body radiation, the interaction between light and matter has played a critical role in the development of quantum mechanics.
Haroche's experiment was able to detect, without destroying, the presence of single photons in a cavity cooled to 0.8K. This allowed him to "see" the birth and death of black body radiation photons. Being able to detect single photons without destroying them has important implications for quantum information. I have always been taken by how this experiment connects Planck's work with quantum information, forming a beautiful narrative that spans more than a century of physics. This is only one of several incredible experiments by Haroche that contributed to his selection for the 2012 Nobel Prize in physics.
I am also continually amazed by Henry and the quality, both in presentation and content, of his videos.