Transfer of orbital angular momentum of light using electromagnetically induced transparency

Abstract

We experimentally investigate the transfer of orbital angular momentum (OAM) of light in a solid driven by electromagnetically induced transparency (EIT). Under the condition of dynamical EIT, the OAM of the probe pulse is stored and retrieved in the experimental medium. By using a four-level double-lambda system to control the retrieval process of EIT storage, we show that OAM can be transferred from the probe field or the second control field to the newly generated signal field, which has a new spatial-frequency mode compared with the input mode. Furthermore, we use EIT-based four-wave mixing to investigate the direct OAM transfer without experiencing the storage, where we do not need to switch off and back on the control field.