1、October 2011 Translation by DIN-Sprachendienst.English price group 17No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).IC
2、S 31.260!$t“1819390www.din.deDDIN EN ISO 21254-2Lasers and laser-related equipment Test methods for laser-induced damage threshold Part 2: Threshold determination (ISO 21254-2:2011)English translation of DIN EN ISO 21254-2:2011-10Laser und Laseranlagen Prfverfahren fr die laserinduzierte Zerstrschwe
3、lle Teil 2: Bestimmung der Zerstrschwelle (ISO 21254-2:2011)Englische bersetzung von DIN EN ISO 21254-2:2011-10Lasers et quipements associs aux lasers Mthodes dessai du seuil dendommagement provoqu par laser Partie 2: Dtermination du seuil (ISO 21254-2:2011)Traduction anglaise de DIN EN ISO 21254-2:
4、2011-10Together with DIN EN ISO 21254-1:2011-10,supersedesDIN EN ISO 11254-1:2000-11andDIN EN ISO 11254-2:2002-10www.beuth.deIn case of doubt, the German-language original shall be considered authoritative.Document comprises 42 pages0 .119 DIN EN ISO 21254-2:2011-10 A comma is used as the decimal ma
5、rker. National foreword This standard has been prepared by Technical Committee ISO/TC 172 “Optics and photonics”, Subcommittee SC 9 “Electro-optical systems” in collaboration with Technical Committee CEN/TC 123 “Lasers and photonics” (Secretariat: DIN, Germany). The responsible German body involved
6、in its preparation was the Normenausschuss Feinmechanik und Optik (Optics and Precision Mechanics Standards Committee), Working Committee NA 027-01-18 AA Laser. EN ISO 21254 consists of the following parts, under the general title Lasers and laser-related equipment Test methods for laser-induced dam
7、age threshold: Part 1: Definitions and general principles Part 2: Threshold determination Part 3: Assurance of laser power (energy) handling capabilities Part 4: Inspection, detection and measurement Technical Report The DIN Standard corresponding to the International Standard referred to in this do
8、cument is as follows: ISO 11145 DIN EN ISO 11145 Amendments This standard differs from DIN EN ISO 11254-1:2000-11 and DIN EN ISO 11254-2:2002-10 as follows: a) the 1-on-1 test has been transferred from ISO 11254-1; b) definitions and general principles have been transferred to ISO 21254-1. Previous
9、editions DIN EN ISO 11254-1: 2000-11 DIN EN ISO 11254-2: 2002-10 National Annex NA (informative) Bibliography DIN EN ISO 11145, Optics and photonics Lasers and laser-related equipment Vocabulary and symbols 2 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 21254-2 July 2011 ICS 31.260 Super
10、sedes EN ISO 11254-1:2000, EN ISO 11254-2:2001English Version Lasers and laser-related equipment - Test methods for laser-induced damage threshold - Part 2: Threshold determination (ISO 21254-2:2011) Lasers et quipements associs aux lasers - Mthodes dessai du seuil dendommagement provoqu par laser -
11、 Partie 2: Dtermination du seuil (ISO 21254-2:2011) Laser und Laseranlagen - Prfverfahren fr die laserinduzierte Zerstrschwelle - Teil 2: Bestimmung der Zerstrschwelle (ISO 21254-2:2011) This European Standard was approved by CEN on 14 July 2011. CEN members are bound to comply with the CEN/CENELEC
12、Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to
13、 any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the officia
14、l versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovak
15、ia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Management Centre: Avenue Marnix 17, B-1000 Brussels 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 21254-2:2011: EEUROPEAN COMMITTEE FOR STANDARDIZATION COMIT
16、EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Contents Page Foreword .3 Introduction.4 1 Scope5 2 Normative references5 3 Terms and definitions .5 4 Test methods .5 4.1 General .5 4.2 1-on-1 test method 5 4.3 S-on-1 test method 7 5 Accuracy.11 6 Test report11 6.1 General .11 6.2 1-on-1 tes
17、t.12 6.3 S-on-1 test 12 Annex A (informative) Example of a measurement procedure (1-on-1 test).13 Annex B (informative) Example of a test report for a 1-on-1 test.19 Annex C (informative) Example of a measurement procedure (S-on-1 test) 24 Annex D (informative) Example of a test report for an S-on-1
18、 test28 Annex E (informative) Extrapolation method for S-on-1 tests .35 Annex F (informative) Conversion of damage data into defect densities.37 Bibliography DIN EN ISO 21254-2:2011-10 EN ISO 21254-2:2011 (E) 240Foreword This document (EN ISO 21254-2:2011) has been prepared by Technical Committee IS
19、O/TC 172 “Optics and photonics“ in collaboration with Technical Committee CEN/TC 123 “Lasers and photonics” the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by
20、 January 2012, and conflicting national standards shall be withdrawn at the latest by January 2012. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such p
21、atent rights. This document supersedes EN ISO 11254-1:2000, EN ISO 11254-2:2001. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republ
22、ic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 21254-2:2011 has b
23、een approved by CEN as a EN ISO 21254-2:2011 without any modification. DIN EN ISO 21254-2:2011-10 EN ISO 21254-2:2011 (E) 3Introduction This part of ISO 21254 specifies test methods for determining single-shot and multiple-shot laser-induced damage thresholds (LIDTs) of optical components, both coat
24、ed and uncoated. The aim is to provide methods which will enable measurement results to be obtained which are consistent and can be rapidly and accurately compared between different test laboratories. In the single-shot test, which is referred to as the 1-on-1 test in this International Standard, ea
25、ch unexposed site on the sample surface is subjected to only one pulse of laser radiation. Repeated laser radiation pulses can damage optical components, or otherwise cause them to deteriorate, at irradiation levels below those measured for single-shot damage. Besides reversible effects induced by t
26、hermal heating and distortion, irreversible damage due to ageing, microdamage and the generation or migration of defects is observed. The degradation of the optical quality is a function of the laser operating parameters and the optical system in which the component is located. The multiple-shot tes
27、t, referred to as the S-on-1 test, is based on a protocol that uses a series of pulses with constant energy density at each unexposed test site. In addition to an evaluation technique based on the survival curve for 1-on-1 tests, this part of ISO 21254 also describes two methods for the reduction of
28、 raw data obtained from S-on-1 damage tests: one using the characteristic damage curve and the other an extrapolation technique. The characteristic damage curve method calls for S-on-1 testing at a large number of sites on the optical surface of the specimen and generation of a set of three graphs i
29、ndicating energy density values corresponding to probabilities of damage of 10 %, 50 % and 90 % for a selected number of pulses. The characteristic damage curve represents the results of a complete and extended laser-induced damage test, and it is recommended for basic investigations in newly develo
30、ped or critical laser optics. The second method of S-on-1 testing, the extrapolation method, uses a considerably smaller number of test sites. This method generates a distribution diagram of the damaged and undamaged regions for the behaviour of the damage threshold as a function of the number of pu
31、lses per site. This diagram is of limited reliability but may be employed for the quality control of optical laser components which have already been qualified by a complete damage test or as part of the preparation for extended damage testing. Realistic laser damage tests suitable for industrial ap
32、plications require a large number of pulses (109to 1011pulses) and hence involve a disproportionate experimental cost. This part of ISO 21254 therefore also outlines a procedure for obtaining the S-on-1 threshold by extrapolation of the characteristic damage curve in order to estimate the real lifet
33、ime of an optical component. NOTE It should be realized that the laser-induced damage threshold of an optical component which is subjected to repeated pulses of radiation can be affected by a variety of different degradation mechanisms, including contamination, thermal heating, migration or generati
34、on of internal defects, and structural changes. These mechanisms are influenced by the laser operating parameters, the environment and the component mounting conditions. For these reasons, it is necessary to record all the parameters and to bear in mind that the damage behaviour might differ in test
35、s carried out in different operating conditions. The test procedures described in this part of ISO 21254 are applicable to all combinations of laser wavelengths and pulse lengths. However, comparison of laser damage threshold data can be misleading unless the measurements have been carried out at th
36、e same wavelength, using the same pulse length and beam diameter. Definitions and the general principles of laser-induced damage threshold measurements are given in ISO 21254-1. DIN EN ISO 21254-2:2011-10 EN ISO 21254-2:2011 (E) 4WARNING The extrapolation of damage data can lead to an overestimation
37、 of the laser-induced damage threshold. In the case of toxic materials (e.g. ZnSe, GaAs, CdTe, ThF4, chalcogenides, Be, Cr, Ni), this can lead to serious health hazards. See ISO 21254-1:2011, Annex A, for further comments. 1 Scope This part of ISO 21254 describes 1-on-1 and S-on-1 tests for the dete
38、rmination of the laser-induced damage threshold of optical laser components. It is applicable to all types of laser and all operating conditions. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition c
39、ited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 11145, Optics and photonics Lasers and laser-related equipment Vocabulary and symbols ISO 21254-1:2011, Lasers and laser-related equipment Test methods for laser-induced damage
40、 threshold Part 1: Definitions and general principles 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 11145 and ISO 21254-1 apply. 4 Test methods 4.1 General The general principles of laser-induced damage threshold measurements, and the apparatus and
41、 sampling techniques used, are described in ISO 21254-1. 4.2 1-on-1 test method 4.2.1 General In the 1-on-1 test, each unexposed site on the surface of the sample is exposed to a single laser pulse with defined beam parameters. From the experimental data, a plot depicting the probability of damage a
42、s a function of the energy density or power density is constructed. DIN EN ISO 21254-2:2011-10 EN ISO 21254-2:2011 (E) 54.2.2 Test parameters The test equipment shall be characterized by the parameters described in ISO 21254-1:2011, 6.2.6.5. 4.2.3 Procedure Test sites are positioned in the beam and
43、irradiated by single shots of laser radiation with different energy densities or power densities. Expose a minimum of ten sites to one preselected pulse energy (or beam power) and record, for each site, the actual pulse energy (or beam power) measured by the beam diagnostic unit as well as the state
44、 of damage after irradiation (damage or no damage). Repeat this sequence for other pulse energies or beam powers. The range of pulse energies or beam powers employed shall be sufficiently broad to include low values which result in no damage at any site and sufficiently high values which induce dama
45、ge at each site tested. 4.2.4 Evaluation of measurements Damage threshold data are obtained by the damage-probability method. To construct a plot of the probability of damage versus the quantity in terms of which the laser-induced damage threshold is to be expressed, the probability of damage is det
46、ermined for each energy-density or power-density increment by calculating the ratio of the number of damaged sites to the total number of sites tested. Linear extrapolation of the damage-probability data to zero damage probability yields the threshold value. An example is shown in Figure 1. Key X en
47、ergy, in millijoules Y damage probability NOTE The test conditions were as follows: d86,5= 1,44 mm, = 10,6 m, H= 100 ns, tail 3,5 s (TEA CO2laser), specimens: KBr windows, 50 items, diameter 40 mm. Figure 1 Graph for the determination of the damage threshold from experimental data DIN EN ISO 21254-2
48、:2011-10 EN ISO 21254-2:2011 (E) 6In the case of a laser system with a high pulse-to-pulse energy variation, it is permissible to expose the specimen to arbitrary pulse energies and to sort the data with respect to appropriate energy intervals after the test. NOTE 1 Examples of an efficient measurement procedure giving maximum accuracy for a given number of sites are presented in Annex A and Annex C for the 1-on-1 and the S-on-1 test, respectively. NOTE 2 The diameter of the test beam at the specime
