Intensity and polarization switching behaviors of light emission induced with a scanning tunneling microscope

By applying voltage pulses across the tunnel junction, switching behaviors of the intensity and the polarization of light emission induced with a scanning tunneling microscope (STM) are observed. The STM images taken subsequently indicate that these switching behaviors are caused by a cluster with asymmetric shape on the nanometer scale being transferred between the sample and the tip by the pulse applied. Possible mechanisms for the switching behaviors are discussed. These observations could find applications in photonic devices on the nanometer scale.