Wavelength dependence of nonsequential double ionization in He

Abstract

An enhancement of the ${\mathrm{He}}^{2+}$ yield near the appearance intensity was not observed by linearly polarized KrF laser light (248 nm), whereas a significant enhancement was observed by linearly polarized Ti:sapphire laser light (745 nm). These results are consistent with the quasistatic model proposed by Corkum [Technical Digest of Short Wavelength V: Physics with Intense Laser Pulses (Optical Society of America, Washington, DC, 1993), p. 25].