Affiliation:
1. Department of Photoelectric Engineering, Xi’an Technological University , 2 Xuefu Zhonglu, Wei yang District , Xi’an , Shaanxi, 710021 , China
Abstract
Abstract
In a high-power laser system, when the surface pressure of the optical film caused by laser plasma shock wave is greater than the adhesion per unit area of the film layer, the film will produce mechanical damage, and in serious cases, the whole system may not work. Therefore, studying the formation mechanism of optical film surface pressure and impulse caused by laser plasma shock wave is the key to ensure the normal operation of the high-power laser system. In this article, by studying the relaxation process of laser plasma shock wave on the surface pressure of optical film, and using the time accumulation effect of various pressures on the surface of the optical film, the calculation model of impulse on the optical film’s surface formed by laser plasma shock waves was established, and the variation rules of the impulse
I
st
{I}_{\text{st}}
and impulse coefficient
j
j
on the unit area of single-layer Al2O3 and HfO2 optical films with different parameters were obtained. When the incident laser wavelength
λ
\lambda
was 1,064 nm, the energy
E
E
was
0.1
J
0.1\hspace{.1em}\text{J}
, the pulse width
t
p
{t}_{\text{p}}
was
10
ns
10\hspace{.25em}\text{ns}
, the focal length of the focusing lens
f
f
was
350
mm
350\hspace{.25em}\text{mm}
, the distance between the film surface and the focal plane of the focusing lens
z
0
{z}_{0}
was
5
mm
5\hspace{.5em}\text{mm}
, and the film radius
R
R
was
5
mm
5\hspace{.5em}\text{mm}
, the calculation and simulation results show that the impulse
I
st
{I}_{\text{st}}
of the two films was
1
0
−
4
N
s
1{0}^{-4}\hspace{.5em}\text{N}\hspace{.5em}\text{s}
order of magnitude, the impulse coefficient j of the two films was
1
0
−
5
N
s/J
1{0}^{-5}\hspace{.5em}\text{N}\hspace{.5em}\text{s/J}
, the Al2O3 film with small atomic number will obtain larger
I
st
{I}_{\text{st}}
and
j
j
,
I
st
{I}_{\text{st}}
and
j
j
of the two films increase with the increase of
E
E
and
f
f
, and
I
st
{I}_{\text{st}}
and
j
j
of the two films decrease with the increase of
z
0
{z}_{0}
and
t
p
{t}_{\text{p}}
. In the total impulse transfer time (
t
0
{t}_{0}
),
I
st
{I}_{\text{st}}
and
j
j
both increase with the increase of
R
R
.
Subject
General Physics and Astronomy