3-10 State-selective Spontaneous Evolution of Rydberg Atoms into an Ultracold Plasma

摘要

We measured the state distribution of cold Rydberg atoms for various initially excited Rydberg levels and evolution times in order to investigate the collision-induced dynamics.The cold Rydberg atoms were excited into nP states(n=20,25,30,…,97)below the ionization potential.Immediately after the excitation the hot electrons were detected as shown in Fig.1(a),which are due to the slow ionization caused by the collision between hot Rydberg atoms and cold Rydberg atoms[1].A pulsed electric field(~300 mV/cm)was applied after few microseconds and obtained a second peak,that indicates the plasma electrons.