Laser Induced Damage Threshold (LIDT):
(S-on-1 test procedure: ISO 11254 – 2)
Request/contact person
UAB “Altechna” Konstitucijos pr. 23C
LT-08105 Vilnius (A. Galinis)
Testing institute
Testing institute:
Tester/date:
Vilnius University,
Laser Research Center,
Saulėtekio al. 10,
Vilnius, Lithuania
A. Melninkaitis/2011-09-19
Specimen
Name of sample:
Type of specimen:
Storage, cleaning:
Notch filter;
Filter, AOI=45;
Wrapping paper, no cleaning.
Test specification
Second harmonic of pulsed Nd:YAG NL303 G laser ( = 532 nm, linear
polarization S, pulse duration 2,5 ns), /2 plate combined with additional
polarizer attenuator, online scattered light damage detection, offline
inspection of damage detection using Nomarski microscopy (100x).
Laser parameters
Wavelength:
Angle of incidence:
Polarisation state:
Pulse repetition frequency:
Spatial beam profile in target plane:
Longitudinal beam profile:
Beam diameter in target plane(1/e2):
Pulse duration:
532 nm;
45 deg;
linear S;
10 Hz;
TEM00;
Multimode;
170,2 µm (average from 30 pulses);
2,5 ± 0,4ns;
Fig. 1. Spatial beam profile in target plane and pulse duration
graph.
Test procedure:
S-on-1 test
Number of sites per specimen:
Arrangement of test sites:
Minimum distance between sites:
Damage detection:
Storage of the specimen:
Test environment:
Cleaning:
Definition of LIDT:
456;
Equally spaced;
721 m;
Scattered light diode;
Plastic container;
Industrial environment;
No;
Linear fit to 0% of damage probability;
Test result of Notch filter
Front surface:
LIDT 1-on-1 = 5,55 ± 0,72 J/cm2
LIDT 1000-on-1 = 2,02 ± 0,58 J/cm2
Rear surface:
LIDT 1-on-1 = 6,50 ± 0,76 J/cm2
LIDT 1000-on-1 = 4,75 ± 0,69 J/cm2
Fig. 2. Characteristic damage curve.
Fig. 3. Typical front surface damage morphology
(Energy density 8,68 J/cm2, damage after 1 pulse)
Fig. 4. Typical front surface damage morphology
(Energy density 4,11J/cm2, damage after 205 pulses)
Fig. 5. Typical rear surface damage morphology
(Energy density 8,81J/cm2, damage after 1 pulse)
Fig. 6. Typical rear surface damage morphology
(Energy density 8,88J/cm2, damage after 2 pulses)
Technical Note 1
According to the ISO11254-2 norm for spatial beam profiling perpendicular to
the direction of beam propagation and angles of incidence differing from
0 degrees, the cosine of the angle of incidence has to be included in the
calculation of the effective area. Therefore the beam diameter increase due
to the angle of incidence (AOI) is taken into account when calculating the
laser fluency.
Laser beam area A (1/e2):
(Perpendicular to the
propagation direction)
Sample
= 45 deg
Area A’= (Area A)/cos())
(projection A’ of area A in the
target plane @ 45 deg AOI)
Fig. 7.