The energy scale of atomic or molecular transitions is of order eV or less, which is closer to the neutrino mass scale suggested by the neutrino oscillation experiments. In this talk, I propose a new approach to clarify unknown properties of neutrinos using atomic or molecular processes. After introducing the relevant process, radiative emission of neutrino pair (RENP), I explain the macrocoherent amplification that is necessary to observe RENP. I also mention the possibility to detect the cosmic neutrino background with RENP. In addition some experimental results that exhibit the macrocoherent amplification in a QED process are described.
