Spectroscopy of Rydberg states in erbium using electromagnetically induced transparency

Abstract

We present a study of the Rydberg spectrum in Er166 for series connected to the 4f12(H63)6s, Jc=13/2, and Jc=11/2 ionic core states using an all-optical detection based on electromagnetically induced transparency in an effusive atomic beam. Identifying approximately 550 individual states, we find good agreement with a multichannel quantum defect theory (MQDT) which allows assignment of most states to ns or nd Rydberg series. We provide an improved accuracy for the lowest two ionization thresholds to EIP,Jc=13/2=49260.750(1)cm-1 and EIP,Jc=11/2=49701.184(1)cm-1 as well as the corresponding quantum defects for all observed series. We identify Rydberg states in five different isotopes, and states between the two lowest ionization thresholds. Our results open the way for future applications of Rydberg states for quantum simulation using erbium and exploiting its special open-shell structure.