
100
Laser-Induced Damage in Optical Materials
details of band structure. emost striking result is that the cosine dispersion rela-
tion results in a strong singularity on dependence of the photoionization rate on
laser parameters (Gruzdev 2007) at the following value of the adiabatic parameter
(Equation 4.37):
χ = ξ
1
= 2.4048, (4.41)
where ξ
1
= 2.4048 is the rst root of the Bessel function J
0
(x). Corresponding electric
eld,
F
TH
=
⋅
⋅
ω
ξ
1
, (4.42)
Intensity (W/cm
2
)
10
9
Ionization rate w (fs
1
/
cm
3
)
10
10
(a)
10
–15
10
–10
10
–5
10
0
10
5
10
10
10
15
10
11
10
12
10
13
e Keldysh model
Cosine model
Wavelength: 825 nm
Intensity (W/cm
2
)
10
9
Ionization rate w (fs
1
/cm
3
)
10
10