Phase regulated suppression and enhancement switches of four-wave mixing and fluorescence

We experimentally study the phase regulated switch between electromagnetically induced transparency and electromagnetically induced absorption in probe transmission signal and the conversion between enhancement and suppression in four-wave mixing and fluorescence signals for the first time. By changing the relative phase, electromagnetically induced transparency can be converted into electromagnetically induced absorption. In this process, the conversion from suppression to enhancement is also obtained in four-wave mixing and fluorescence signals. This research can be applied in non-linear optical device like optical switch and optical wavelength convertor.