Stimulated-Raman-Scattering-Assisted Superfluorescence Enhancement From Ionized Nitrogen Molecules In 800-Nm Femtosecond Laser Fields

We have observed collective spontaneous emission (superfluorescence) from ionized nitrogen molecules generated by 800-nm laser pulses. The superfluorescence intensity around 391 nm was found to be greatly enhanced when injecting an external seed with various wavelengths. Our finding provides insights into controlling the coherent emission from air filamentation induced by intense femtosecond laser fields, which has great potential application in remote atmospheric sensing.