This paper summarizes our results of S-on-1 testing carried out over the last few years. Our experimental data sets were
taken with nanosecond laser pulse durations. An attempt was made to use the same scaling laws with femtosecond pulse
widths but it was not successful. The conclusion was made: there is no single model than can universally applied to all
kinds of survivability curves. We present this summary with a particular goal of making recommendations to those
involved in the periodic review of ISO 21254. A preliminary review of models, describing damage threshold evolution
with respect to incident laser pulses, is made.
In this paper, we report on a continuing multi-year empirical investigation into the nature of the laser
survivability curve. The laser survivability curve is the onset threshold as a function of shot number. This
empirical investigation is motivated by the desire to design a universal procedure for the measurement
of the so-called S on 1 damage threshold. In this year’s paper we investigate the usefulness of scaling
the fluence with shot number. First the scaling process is defined and applied to a result from our
experimental archives. The probability of damage curve for a single shot test is extrapolated to 10<sup>4</sup>
shots. The scaled result is shown to be very close the observed results providing a basis for extrapolation
to very large values of n.
This paper presents a first look at the application of maximum likelihood estimation methods to S on 1
testing by comparing results with an analysis that is typical of our previous reports and consistent with
ISO 21254. In traditional, ISO tests, the data collected from an S on 1 test is processed to give a set of
fluences representing the no-damage or safe operating fluence (SOF) as a function of the number of
shots. The (SOF,N) ordered pairs are then fitted to a model and the model is used to extrapolate the SOF
to large values of N. In the present report, the entire data set from an ISO S on 1 test is processed via
maximum likelihood methods to estimate the probability curve as a function of fluence, P(Φ). The
probability of survival to N shots is calculated, under the assumption that P is independent of N, to give
the final results. The maximum likelihood method shows promise for application to S on 1 testing.
In this paper, we give the third installment of our ongoing investigation into the nature of the laser
survivability curve (LSC). In this year’s report, We examine a set of identically polished samples coated with
the same AR coating design. One set coated using IAD process and the other e-beam. In the samples
investigated show similar asymptotic behavior within manufacturing methods, but each technique behaves
In this paper, we report on the second installment of our ongoing investigation into the nature of the
laser survivability curve (LSC). The LSC has been traditionally viewed as a curve in the plane defined by
fluence,φ , and the number of shots, N, which defines the frontier of assured survival. In this year's
report we expand the concept of the survivability curve to a surface of survival, the laser survival surface
(LSS), which is in turn used to develop a conditional probability estimate for survival. This conditional
probability viewpoint is discussed as a possible basis for a
cost-efficient life time test. The LSS is
developed for test results at 1064 nm wavelength taken at atmospheric pressure and at vacuum.
In this paper, we report on the first steps in an empirical investigation into the nature of the laser survivability curve.
The laser survivability curve is the onset threshold as a function of shot number. This empirical investigation is
motivated by the desire to design a universal procedure for the measurement of the so-called S on 1 damage
threshold. Analysis is carried on the test results for first results from a large set of planned measurements from
identical samples produced for this investigation. The sample set and test conditions are discussed. A pair of
measurements, one taken at atmospheric pressure and one at vacuum are introduced and analyzed as an example.
Interim observations on the nature of the laser survivability curve, and its determination to be used in the remainder
of this investigation based on this initial look, are presented at the conclusion of this paper.
In this paper, we present test results and involved procedures of a comprehensive test campaign for S on 1 testing of laser
optics with large test areas allowing the generation of a profound test database for further analysis. This database will serve
as a starting point for an empirical study of the lifetime of laser optics, which will be discussed in companion paper
somewhere in these proceedings.
The optics are designed to operate as anti-reflective or high-reflective components at the respective test wavelengths for 0° angle-of-incidence. Both, coatings and substrates of 2.0 inch diameter are produced from the same batches to be as identical
as possible. There were two different coating technologies used, e-beam and IAD e-beam, to explore a possible effect of the
coating process on the long term laser irradiation behavior.
The laser damage test bench is operated with a laser source delivering laser pulses in a single longitudinal mode at a
repetition frequency of 100 Hz. The beam profile is of a
Gaussian-shape and of high spatial quality at the fundamental
Nd:YAG laser wavelength with a pulse duration of 3.5 ns at 1064 nm. Typical beam diameters on the samples were 400
μm, and usually more than 500 test sites are irradiated in one test to achieve statistical significance. The laser test procedure
itself is adapted from the ISO standard 11254-2 for multiple pulse irradiations, and the LIDT evaluation is done
A comparison of ion assisted deposition (IAD) and non-IAD e-beam coatings on BBO crystals was performed. Samples of BBO were processed as a lot and prepared for coatings using standard solvent cleaning. Two types of coatings were tested; a dual peak anti-reflection, 1064nm and 532nm, and a triple peak anti-reflection, 1064nm, 532nm and 355nm. After depositing of these high laser damage resistant coatings the transmission, reflection and absorption of each coating was measured. Each of the coatings laser damage threshold was determined and an analysis of the two methods of deposition was performed. Additionally, after MIL spec humidity tests were performed on each of the samples, spectral shifts were analyzed for both types of coatings. Conclusions were drawn about the preferred method of deposition for the improvement for spectral characteristics, increased laser damage resistance and reduction of humidity induced spectral shifts.