Amplification of 126 nm femtosecond pulses in optical-field-induced Ar plasma filamentation

Plasma diagnosis revealed that the electron density of an optical-field-induced Ar
₂
* amplifier was larger than 10
¹⁸
cm
^-3
after 100 ns of the plasma production, which resulted in the 126 nm optical gain of 1.1 cm
^-1
.