Plasma formation during operation of diode (DPAL) and excimer (XPAL) pumped alkali lasers

Summary form only given. Large densities of alkali excited states are produced during operation of the diode (DPAL) and excimer (XPAL) pumped alkali laser. Through superelastic electron collision-al relaxation of these states, any pre-existing electrons can be heated, leading to additional ionization. Lasing on the D
₁
transition (6
²
P
_1/2
→ 6
²
S
_1/2
) of Cs can be achieved in both diode and excimer pumped alkali lasers. The first uses the D
₂
transition (6
²
P
_3/2
→ 6
²
S
_1/2
) for pumping, whereas the second is pumped by photoexcitation of ground state Cs-Ar collisional pairs and subsequent dissociation of diatomic, electronically-excited CsAr molecules (excimers). In spite of lasing on the same D
₁
transition, differences in pumping schemes enable different chemical pathways and characteristic timescales which are unique for each system. We have developed a global model to investigate the operation of DPAL and XPAL side-by-side in Ar/Cs/C
₂
H
₆
system. Plasma characteristics and their impact have been investigated as a function of pump power, cell temperature and excitation frequency.