1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN ISO 21254-2:2011Lasers and laser-relatedequipment Test methodsfor laser-induced damagethresholdPart 2: Threshold determination (ISO21254-2:2011)BS EN ISO 21254-2:2011 BRITI
2、SH STANDARDNational forewordThis British Standard is the UK implementation of EN ISO21254-2:2011. Together with BS EN ISO 21254-1:2011, it supersedesBS EN ISO 11254-1:2000 and BS EN ISO 11254-2:2001 which arewithdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee CPW/17
3、2/9, Electro-optical systems.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2011ISBN 978 0 580 52999 3ICS 31
4、.260Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 30 September 2011.Amendments issued since publicationDate Text affectedEUROPEAN STANDARD NORME EUROPENNE EUROPI
5、SCHE NORM EN ISO 21254-2 July 2011 ICS 31.260 Supersedes 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
6、 dessai du seuil dendommagement provoqu par laser - 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. CE
7、N members are bound to comply with the CEN/CENELEC 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 app
8、lication to the CEN-CENELEC Management Centre or to 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 M
9、anagement Centre has the same status as the official 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, Net
10、herlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2011 CEN All rights of exploitatio
11、n in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 21254-2:2011: EBS EN ISO 21254-2:2011EN ISO 21254-2:2011 (E) 3 Foreword This document (EN ISO 21254-2:2011) has been prepared by Technical Committee ISO/TC 172 “Optics and photonics“ in collaboration with Tec
12、hnical 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 January 2012, and conflicting national standards shall b
13、e 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 patent rights. This document supersedes EN ISO 11254-1:200
14、0, 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 Republic, Denmark, Estonia, Finland, France, Germany, Greece, H
15、ungary, 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 been approved by CEN as a EN ISO 21254-2:2011 without any
16、modification. BS EN ISO 21254-2:2011ISO 21254-2:2011(E) ISO 2011 All rights reserved iiiContents Page Foreword iv Introduction.v 1 Scope1 2 Normative references1 3 Terms and definitions .1 4 Test methods .1 4.1 General .1 4.2 1-on-1 test method 1 4.3 S-on-1 test method 3 5 Accuracy.7 6 Test report7
17、6.1 General .7 6.2 1-on-1 test.8 6.3 S-on-1 test 8 Annex A (informative) Example of a measurement procedure (1-on-1 test).9 Annex B (informative) Example of a test report for a 1-on-1 test.15 Annex C (informative) Example of a measurement procedure (S-on-1 test) 20 Annex D (informative) Example of a
18、 test report for an S-on-1 test24 Annex E (informative) Extrapolation method for S-on-1 tests .31 Annex F (informative) Conversion of damage data into defect densities.33 Bibliography36 BS EN ISO 21254-2:2011ISO 21254-2:2011(E) iv ISO 2011 All rights reservedForeword ISO (the International Organizat
19、ion for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established h
20、as the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Int
21、ernational Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Public
22、ation as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent ri
23、ghts. ISO 21254-2 was prepared by Technical Committee ISO/TC 172, Optics and photonics, Subcommittee SC 9, Electro-optical systems. This first edition of ISO 21254-2:2011, together with ISO 21254-1:2011, cancels and replaces ISO 11254-1:2000 and ISO 11254-2:2001, which have been technically revised.
24、 ISO 21254 consists of the following parts, under the general title Lasers and laser-related equipment Test methods for laser-induced damage threshold: Part 1: Definitions and general principles Part 2 : Threshold determination Part 3: Assurance of laser power (energy) handling capabilities Part 4:
25、Inspection, detection and measurement Technical Report BS EN ISO 21254-2:2011ISO 21254-2:2011(E) ISO 2011 All rights reserved vIntroduction This part of ISO 21254 specifies test methods for determining single-shot and multiple-shot laser-induced damage thresholds (LIDTs) of optical components, both
26、coated 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
27、, each 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
28、by thermal 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
29、 test, 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 reductio
30、n of 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 grap
31、hs indicating 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 de
32、veloped 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 o
33、f pulses 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 industria
34、l applications 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 l
35、ifetime 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 gene
36、ration 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
37、tests 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 a
38、t the 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. BS EN ISO 21254-2:2011BS EN ISO 21254-2:2011INTERNATIONAL STANDARD ISO 21254-2:2011(E) ISO 2011 All rights reserved 1L
39、asers and laser-related equipment Test methods for laser-induced damage threshold Part 2: Threshold determination WARNING The extrapolation of damage data can lead to an overestimation of the laser-induced damage threshold. In the case of toxic materials (e.g. ZnSe, GaAs, CdTe, ThF4, chalcogenides,
40、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 determination of the laser-induced damage threshold of optical laser components. It is applicable to all types of laser
41、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 cited applies. For undated references, the latest edition of the referenced document (including any amendments) appli
42、es. 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 threshold Part 1: Definitions and general principles 3 Terms and definitions For the purposes of this document, the
43、 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 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, ea
44、ch 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 as a function of the energy density or power density is constructed. BS EN ISO 21254-2:2011ISO 21254-2:2011(E) 2 ISO
45、2011 All rights reserved4.2.2 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 irradiated by single shots of laser radiation with different energy densities or power densities
46、. 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 of damage after irradiation (damage or no damage). Repeat this sequence for other pulse energie
47、s 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 damage at each site tested. 4.2.4 Evaluation of measurements Damage threshold data are obtained by t
48、he 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 determined for each energy-density or power-density increment by calculating the ratio of the numbe
49、r 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 energy, 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 BS EN ISO 21254-2:2011ISO 21254-2:201
