Switching of the two competing amplified spontaneous emission channels in NO

Switching of the two competing amplified spontaneous emission (ASE) channels is reported for the first time. The principle is based upon a characteristic of the ASE process that amplification occurs above a certain threshold of the population inversion density. We demonstrated that one of the two ASE channels could be suppressed almost completely by pre-populating the corresponding lower level. Enhancement of the other ASE channel implies the possibility of manipulating population transfer in molecular system.