Ellipticity dependence of frustrated tunneling ionization in argon atoms.*

Following tunneling ionization by a strong, few-cycle infrared pulse, a portion of the ionized electrons can recombine into a bound state through Frustrated Tunneling Ionization (FTI)~[1,2]. A recent joint experimental and theoretical study on argon atoms, with emphasis on metastable production by linearly polarized light, was reported by Chetty et al.~[3]. By increasing the ellipticity of the driving laser pulse, the liberated electron is driven further away from the ion, thereby reducing the probability of recombination into a bound state. The ellipticity dependence of FTI was previously studied both theoretically~[1] and experimentally~[4] in helium. Here we present predictions for the theoretically more challenging argon target, employing both multi-electron~[4] and single-active electron~[5] theoretical techniques to compliment experimental efforts currently in progress~[7]. [1] T.~Nubbemeyer et al., Phys.\ Rev.\ Lett.~{\bf 101} (2008) 233001. [2] H.~Zimmermann et al., Phys.\ Rev.\ Lett.~{\bf 118} (2017) 013003. [3] D.~Chetty et al., arXiv:1912.06280v1 (2019). [4] H.~Yun et al., Nat.\ Phot.~{\bf 12} (2018) 620-624. [5] A.~C.~Brown et al., Comput.\ Phys.~(2019) 107062. [6] N.~Douguet et al., Phys.\ Rev.\ A~{\bf 93} (2016) 033402. [7] I.~Litvinyuk, priv.\ commun.~(2020).