1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN ISO 21254-3:2011Lasers and laser-relatedequipment Test methodsfor laser-induced damagethresholdPart 3: Assurance of laser power (energy)handling capabilities (ISO 21254-3:2
2、011)BS EN ISO 21254-3:2011 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN ISO21254-3:2011. It supersedes BS EN ISO 11254-3:2006 which iswithdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee CPW/172/9, Electro-optical systems.A li
3、st 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 53000 5ICS 31.260Compliance with a British Sta
4、ndard 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 EUROPISCHE NORM EN ISO 21254-3 July 201
5、1 ICS 31.260 Supersedes EN ISO 11254-3:2006English Version Lasers and laser-related equipment - Test methods for laser-induced damage threshold - Part 3: Assurance of laser power (energy) handling capabilities (ISO 21254-3:2011) Lasers et quipements associs aux lasers - Mthodes dessai du seuil dendo
6、mmagement provoqu par laser - Partie 3: Possibilits de traitement par puissance (nergie) laser (ISO 21254-3:2011) Laser und Laseranlagen - Prfverfahren fr die laserinduzierte Zerstrschwelle - Teil 3: Zertifizierung der Belastbarkeit hinsichtlich Laserleistung (-energie) (ISO 21254-3:2011) This Europ
7、ean Standard was approved by CEN on 14 July 2011. CEN 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 conce
8、rning such national standards may be obtained on application 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 int
9、o its own language and notified to the CEN-CENELEC Management 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, Irela
10、nd, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, 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
11、, 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 21254-3:2011: EBS EN ISO 21254-3:2011EN ISO 21254-3:2011 (E) 3 Foreword This document (EN ISO 21254-3:2011) has been prepared by Technical Committee ISO/TC
12、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 Janu
13、ary 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 patent
14、 rights. This document supersedes EN ISO 11254-3:2006. 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, Finl
15、and, 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 21254-3:2011 has been approved by CEN as a E
16、N ISO 21254-3:2011 without any modification. BS EN ISO 21254-3:2011ISO 21254-3:2011(E) ISO 2011 All rights reserved iiiContents Page Foreword iv Introduction.v 1 Scope1 2 Normative references1 3 Terms and definitions .1 4 Symbols and units of measurement2 5 Test methods .3 5.1 Principle3 5.2 Test me
17、thods .3 6 Accuracy.6 7 Test report6 Annex A (informative) Example of a test report.7 Annex B (informative) Notes on use .10 Annex C (informative) Details of the derivation of the operating-characteristic curve .14 Bibliography16 BS EN ISO 21254-3:2011ISO 21254-3:2011(E) iv ISO 2011 All rights reser
18、vedForeword ISO (the International Organization 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
19、a technical committee has been established has 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 matt
20、ers of electrotechnical standardization. International 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 circul
21、ated to the member bodies for voting. Publication 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 responsib
22、le for identifying any or all such patent rights. ISO 21254-3 was prepared by Technical Committee ISO/TC 172, Optics and photonics, Subcommittee SC 9, Electro-optical systems. This first edition of ISO 21254-3:2011 cancels and replaces ISO 11254-3:2006, which has been technically revised. ISO 21254
23、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: Inspection,
24、detection and measurement Technical Report BS EN ISO 21254-3:2011ISO 21254-3:2011(E) ISO 2011 All rights reserved vIntroduction This part of ISO 21254 describes two methods of verifying the power density (energy density) handling capability of optical components, both coated and uncoated. The method
25、s will give consistent measurement results and can therefore be used for acceptance testing or to produce results which can be compared between test laboratories. The methods are applicable to all combinations of laser wavelengths and pulse lengths. Comparison of laser damage threshold data can, how
26、ever, be misleading unless the measurements have been carried out at identical wavelengths and pulse lengths. BS EN ISO 21254-3:2011BS EN ISO 21254-3:2011INTERNATIONAL STANDARD ISO 21254-3:2011(E) ISO 2011 All rights reserved 1Lasers and laser-related equipment Test methods for laser-induced damage
27、threshold Part 3: Assurance of laser power (energy) handling capabilities 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, Be, Cr, Ni), this can lead to serious he
28、alth hazards. See ISO 21254-1:2011, Annex A, for further comments. 1 Scope This part of ISO 21254 specifies two methods of verifying the power density (energy density) handling capability of optical surfaces. The first method provides a rigorous test that fulfils the requirements at a specified conf
29、idence level in the knowledge of potential defects. The second method provides a simple, and hence inexpensive, test for an empirically derived test level. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the
30、 edition cited 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-indu
31、ced damage 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 and the following apply. 3.1 assurance level energy density/power density/linear power density of the laser radiatio
32、n incident on the optical surface of the component being tested 3.2 assurance area Aarea over which the value of H(x,y,z) is equal to or greater than the assurance level BS EN ISO 21254-3:2011ISO 21254-3:2011(E) 2 ISO 2011 All rights reserved3.3 confidence level probability of successful completion
33、of the assurance test 3.4 flat-top beam beam which has a broad area of nearly constant peak intensity (or fluence) 3.5 fraction of test area to be exposed ftestproportion of the total area of the optical component which has to be interrogated to achieve a certain confidence level 3.6 area to be test
34、ed Atestarea of the optical component which has to be interrogated to achieve a certain confidence level 3.7 horizontal overlap xproportion of overlapping beam area of two consecutive pulses in direction x 3.8 vertical overlap yproportion of overlapping beam area of two consecutive pulses in directi
35、on y 3.9 distance between test sites dtsseparation of test sites 4 Symbols and units of measurement The symbols and units of measurement are compiled in Table 1. In addition, the terms and definitions given in ISO 21254-1 apply. Table 1 Symbols and units of measurement Symbol Unit Term confidence le
36、vel ftestfraction of test area to be exposed Ndnumber of damage-initiation sites J/cm2, W/cm2, W/cm assurance level Acm2assurance area Atestcm2area to be tested xhorizontal overlap yvertical overlap dtsdistance between test sites BS EN ISO 21254-3:2011ISO 21254-3:2011(E) ISO 2011 All rights reserved
37、 35 Test methods 5.1 Principle This part of ISO 21254 provides methods that will give a high level of confidence in the power density (energy density) handling capability of the component tested. The methods can be used in a wide variety of applications, including: non-destructive testing, witness s
38、ampling, lot sampling and sub-aperture inspection. The level of confidence that the component does not contain a defect with a lower damage threshold than the acceptable irradiation strength increases with the percentage fraction of the area tested. These confidence levels are discussed in Annexes B
39、 and C. Discussions shall be held between the test house and the user/component manufacturer to define the confidence level required and the number of shots per site (1-on-1 or S-on-1 testing) and the pulse-repetition frequency at which the tests are to be carried out. This will define parameters su
40、ch as the assurance area, A, the distance between test sites, dts, and the total number of sites, Nts, to be irradiated. The apparatus for, general principles of and sampling for laser-induced damage testing are described in ISO 21254-1. A laser system with a suitable beam preparation system deliver
41、ing laser radiation with a reproducible flat-top spatial profile is required for the assurance of laser power (energy) handling capabilities. In this test, sampled test sites on the specimen surface are irradiated at an agreed or specified irradiation strength, irradiating in sequence a fraction of
42、the specimen area and verifying that no damage is observed. Enough test sites on the optical surface under test shall be irradiated so that a given confidence level can be established. Since the observation of any damage during a test constitutes a failure, this test can be non-destructive for parts
43、 for which this is considered acceptable. The microscopic examination of the test site before and after irradiation is used to detect any damage. The fluence-handling capability of an optical surface under irradiation by short pulsed lasers is usually expressed in units of energy density, i.e. joule
44、s per square centimetre. The power-handling capability of an optical surface under irradiation by cw (continuous-wave) lasers or quasi-cw lasers is usually expressed in units of linear power density, i.e. watts per centimetre. The proper physical parameter and units for scaling results obtained with
45、 quasi-cw and cw-lasers is the linear power density, expressed in watts per centimetre. 5.2 Test methods 5.2.1 General In tests that sample the ability of a specimen to withstand laser irradiation, it is possible to define two types of test. The first, a type 1 test, allows the determination of a co
46、nfidence level that permits no more than a certain number of defects to exist within the area tested. The type 1 test is described in 5.2.2. The second, a type 2 test, is designed usually empirically, to be used on a specific specimen for a specific use. Such tests are employed to provide cost-effec
47、tive screening at a high rate in an industrial environment. It should be noted that such empirically derived tests were the first widely used laser damage tests in production systems. The criteria that need to be specified to define a type 2 test are given in 5.2.3. BS EN ISO 21254-3:2011ISO 21254-3
48、:2011(E) 4 ISO 2011 All rights reserved5.2.2 Type 1 test Depending on the application, select the assurance level, , the confidence level, , and the number of defects, Nd, per specimen (usually the responsibility of the user). Use Figure 1 to determine the fraction, ftest, of the area to be tested,
49、Atest, that is to be exposed. Determine (by measurement) Afrom the power-density or energy-density profile of the irradiating beam in the target plane. Determine the number of interrogations, Nts, that will need be made to expose the fraction ftestof the surface under test: test testtsAfNA= (1) Determine the distance between test sites, dts, for hexagonal close-packed arrays and for square arrays: testtsts23AdN= for hexagonal close packed arrays (2) testtstsAdN= for square arrays (3) Calculate
