Criticalities and Phase Transitions in the Polarization Switching of Vertical-Cavity Surface-Emitting Lasers

This letter reports on four criticalities observed in the polarization switching (PS) of vertical-cavity surface-emitting lasers (VCSELs). These are a critical slowing down nearing PS, a power law and scaling law of the relaxation time, and an adiabatic no-go, which indicates that the critical point can not be reached adiabatically. The critical exponent of the relaxation time,
$\Delta$
, is measured about 2.3. To our knowledge, this is the first investigation of these criticalities in the VCSEL's PS (VPS). The phase transition characteristics of VPS are also discussed, including the possible connection with the quantum phase transitions.