The lasing action in argon fluoride excimer lasers arises through the following process:

Electric discharge passes through the Ar/F2 gas mix, creating Ar+ ions and electrons.

Accelerated electrons collide with and excite argon atoms.

Excited argon atoms Ar* react with fluorine molecules to form the excimer ArF* in an excited state.

The excimer state spontaneously decays back to unbound argon and fluorine atoms, emitting a 193 nm photon.

Two mirrors form an optical cavity causing stimulated emission and laser oscillation.

This stimulates further excimer formation and decay, releasing more 193 nm photons in phase.

The beam exits through the partially reflective output mirror.

Pumping maintains the electron density and excitation needed for continued lasing action.

The transient excimer state enables efficient UV generation well below conventional laser transitions.