Enhanced fluorescence emission of helium atoms by seeded optically driven impact excitation

We demonstrated enhancement of fluorescence emission from helium atoms in terms of ultraviolet and infrared filaments nonlinear interaction in a mixture of argon and helium atomic gases. The seed electrons produced by ultraviolet pulses were accelerated by infrared filaments to kick a significant amount of helium atoms into high-lying excited states. This provided a method to efficiently excite helium atoms through electron collisions for further investigation on electron-ion collisions and their effects on atomic coherence behavior.