Coherent microwave scattering from xenon resonance-enhanced multiphoton ionization-initiated plasma in air

Here we present the experimental and computational study of resonance-enhanced multiphoton ionization (REMPI) of xenon and subsequent avalanche ionization of air. Xenon was excited from the ground state to the excited 6p state (89 162 cm - 1) by two photons at 224.3 nm. The third photon at 224.3 nm subsequently produced ionization of xenon in air. The seed electrons from the ionization served as the medium to further absorb the laser pulse for the rotational and vibrational excitation and avalanche ionization of O 2 and N 2. Plasma chemistry of O 2 and N 2 in air was included in the model. The results are useful for understanding REMPI-initiated plasma in air and possibly new diagnostics tools based on REMPI-initiated plasma emissions.