Quantum Optics as Applied Quantum Electrodynamics is Back in Town

We start this short note by remembering the beginnings of the Warsaw School of Quantum Optics, evidently stimulated by Iwo Bialynicki-Birula at the Warsaw University, and then Centre for Theoretical Physics of Polish Academy of Sciences and Adam Kujawski and Zofia Bialynicka-Birula at the Institute of Physics of Polish Academy of Sciences. In the theoretical approaches of the Warsaw School, quantum field theory was always present, and quantum optics was considered to be applied quantum electrodynamics. All of us who grew up in this fantastic community have carried and are still carrying the gospel to others. In particular, now quantum electrodynamics began her run on the red carpet of super intense laser-matter interactions, attosecond physics, and ultrafast laser physics in general. We will elaborate on the recent progress in this direction and on the open questions for future investigations. This paper celebrates the 90th birthday of Professor Iwo Bialynicki-Birula, our quantum electrodynamics guru!