1.
Phys Rev Lett
; 124(1): 013201, 2020 Jan 10.
Article
in English
| MEDLINE
| ID: mdl-31976702
ABSTRACT
Strong-field ionization is central to intense laser-matter interactions. However, standard ionization measurements have been limited to extremely low density gas samples, ignoring potential high density effects. Here, we measure strong-field ionization in atmospheric pressure range air, N_{2}, and Ar over 14 decades of absolute yield, using mid-IR picosecond avalanche multiplication of single electrons. Our results are consistent with theoretical rates for isolated atoms and molecules and quantify the ubiquitous presence of ultralow concentration gas contaminants that can significantly affect laser-gas interactions.