1、BSI Standards PublicationBS ISO 17411:2014Optics and photonics Opticalmaterials and components Test method for homogeneityof optical glasses by laserinterferometryBS ISO 17411:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 17411:2014. The UK participation
2、 in its preparation was entrusted to TechnicalCommittee CPW/172, Optics and Photonics.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for i
3、ts correct application. The British Standards Institution 2014.Published by BSI Standards Limited 2014ISBN 978 0 580 80809 8ICS 37.020Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and S
4、trategy Committee on 31 May 2014.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 17411:2014 ISO 2014Optics and photonics Optical materials and components Test method for homogeneity of optical glasses by laser interferometryOptique et photonique Matriaux et composant
5、s optiques Mthode dessai dhomognit des verres optiques par interfromtrie laserINTERNATIONAL STANDARDISO17411First edition2014-06-01Reference numberISO 17411:2014(E)BS ISO 17411:2014ISO 17411:2014(E)ii ISO 2014 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2014All rights reserved. Unless otherw
6、ise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address be
7、low or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 17411:2014ISO 17411:2014(E) ISO 2014 All rights reserved iiiContents PageForewo
8、rd iv1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 15 Measuring apparatus . 25.1 General . 25.2 Laser interferometer 25.3 Interferogram analysis device . 25.4 Thermostatic chamber . 25.5 Vibration isolation device 26 Preparation of sample 27 Operation . 38 Measurement . 3
9、9 Calculation 310 Test report . 4Annex A (informative) Laser interferometer . 6Annex B (informative) Temperature stability for homogeneity measurements 9Annex C (informative) Measuring method using flatness correction plates 11Annex D (informative) Flatness of the sample 13Annex E (informative) Meth
10、od for obtaining PV value of wavefront .15BS ISO 17411:2014ISO 17411:2014(E)ForewordISO (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 t
11、echnical committees. Each member body interested in a subject for which 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 clos
12、ely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria n
13、eeded for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document may be the subject of paten
14、t rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used i
15、n this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barrie
16、rs to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 172, Optics and photonics, Subcommittee SC 3, Optical materials and components.iv ISO 2014 All rights reservedBS ISO 17411:2014INTERNATIONAL STANDARD ISO 17411:2014(E)Op
17、tics and photonics Optical materials and components Test method for homogeneity of optical glasses by laser interferometry1 ScopeThis International Standard specifies the measuring method for the homogeneity of the refractive index of optical glasses by laser interferometry.2 Normative referencesThe
18、 following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 80000-1
19、, Quantities and units Part 1: General3 Terms and definitionsFor the purposes of this document, the following terms and definitions apply.3.1homogeneity of the refractive indexmaximum of the refractive index variations excluding linear changes among refractive index variations within the predetermin
20、ed area in a single glass sample3.2index-matching liquidtransparent liquid with the refractive index which is equivalent or approximate to the refractive index of a glass sample at the wavelength of the laser to be used3.3flatness correction plateplane-parallel plate obtained by polishing an optical
21、 glass with high homogeneity to a high degree of accuracy, e.g. 1/20 of a laser wavelength, which is stuck to a sample by using an index-matching liquid as an intermediate liquid, for the purpose of correcting the flatness of the sample3.4PV value of wavefrontdifference between the maximum and the m
22、inimum deviations of the wavefront, observed when light transmits through a sample once with an interferometer from the approximated plane4 PrincipleThe PV value of wavefront of a luminous flux that transmitted through a sample with sufficient flatness is measured using a laser interferometer, and t
23、he homogeneity of the refractive index of the sample is obtained. ISO 2014 All rights reserved 1BS ISO 17411:2014ISO 17411:2014(E)5 Measuring apparatus5.1 GeneralThe measuring apparatus shall be as shown in Figure 1 and as specified in 5.2 to 5.5.EABCDKeyA thermostatic chamberB interferogram analysi
24、s deviceC laser interferometerD vibration isolation deviceE sampleFigure 1 Example of composition of measuring apparatus5.2 Laser interferometerThe laser interferometer to be used shall have a laser as a light source and an optical system in which the wavefront of a luminous flux forms a plane. Exam
25、ples of such interferometers are given in Annex A.5.3 Interferogram analysis deviceThe interferogram analysis device to be used shall be capable of obtaining the PV value of wavefront from an interferogram.5.4 Thermostatic chamberThe thermostatic chamber to be used shall be capable of maintaining th
26、e interferometer and the sample at a certain temperature. The temperature of the standard atmospheric conditions shall be 20 C, 22 C, 23 C, or 25 C depending on the purpose of testing. The tolerance of the temperatures of the standard atmospheric conditions should be 0,2 C. See Annex B.5.5 Vibration
27、 isolation deviceThe vibration isolation device to be used shall be capable of eliminating the effect of vibration from the outside to the interferometer and the sample system. It should be provided for performing high accuracy measurements.6 Preparation of sampleThe sample shall be cylindrical or p
28、rismatic, and its thickness (height) direction shall be the direction of observation (which is the direction of the optical axis of the luminous flux of an interferometer). The thickness in the direction of observation shall be sufficient to obtain an accurate measured value.2 ISO 2014 All rights re
29、servedBS ISO 17411:2014ISO 17411:2014(E)Both end faces (the faces vertical to the optical axis) of a sample shall be polished so that the flatness of not more than 1/20 of a laser wavelength (when the wavelength is 632,8 nm, approximately 0,032 m) is obtained.When the above-mentioned precision polis
30、hing is not performed, flatness correction plates shall be stuck to the sample using an index-matching liquid as an intermediate liquid, to be supplied for measurement. An example of using flatness correction plates is given in Annex C. In this case, the refractive index of the index-matching liquid
31、 should conform to that of the sample so that the measurement of homogeneity is not affected. The difference of refractive indices between index-matching liquid and the sample should be approximately 0,005 or less. See Annex B.Furthermore, in order to bond the flatness correction plates to the sampl
32、e stably using the refractive index-matching liquid, the flatness of the sample should be approximately 20 m or less. See Annex D.7 OperationThe operation shall be performed as follows.a) Remove dirt from the sample surfaces and correction plates, if used.b) Install the sample in the interferometer
33、so that the predetermined area of the sample fits within the luminous flux of the interferometer. When using flatness correction plates, stick the flatness correction plates to the sample with the index-matching liquid inserted between the sample surfaces and the flatness correction plates. While do
34、ing this, do not allow air bubbles in the intermediate liquid.c) Leave the installed sample to stand until its temperature has returned to the temperature of the measurement environment as given in 5.4. When using flatness correction plates, allow the installed sample with plates to stand until the
35、thickness of the layer of the refractive index-matching liquid between the matched surfaces no longer changes.d) Adjust the optical system of the interferometer so that the number of interference fringes of an interferogram becomes appropriate, and then perform the measurement.e) Obtain the PV value
36、 of wavefront of the luminous flux which transmitted through the sample measuring system from the interferogram.8 MeasurementThe measurement shall be performed as follows.a) The measurement should be performed twice or more by repeating the series of operations described in Clause 7(d) and Clause 7(
37、e). When the average is taken as a measured value, it should be stated in the test report.b) The wavefront irregularities of the optical system of the interferometer and the wavefront irregularities due to the homogeneity of the refractive index and the flatness of a flatness correction plate contri
38、bute errors to the test results. Therefore, for the wavefront of the luminous flux which transmitted through the sample, these errors should be corrected, and the PV value of wavefront should be obtained from the wavefront after correction. An example of the measurement of the PV value of wavefront
39、is given in Annex E.9 CalculationThe calculation of the test result shall be performed as follows.a) The homogeneity of the refractive index shall be calculated according to Formula (1). ISO 2014 All rights reserved 3BS ISO 17411:2014ISO 17411:2014(E)nPtV=(1)wheren is the homogeneity of the refracti
40、ve index;PVis the PV value of wavefront (wavelength unit); is the wavelength of laser (mm);t is the thickness of sample (mm).b) For reporting, the homogeneity of the refractive index shall be rounded to two significant figures in accordance with ISO 80000-1. However, when it is less than 106, it sha
41、ll be rounded to one significant figure.EXAMPLE An example of a calculation is shown below.PVis 0,049 (); is 632,8 106(mm);t is 41 mm.The Formula (2) is givennPtV=0 049 632 810410 756 1066,Since it is less than 106it is roundedtoone significantfigure.,()=n 8107(2)10 Test reportFor the measurement re
42、sult, the following items shall be reported:a) measurement date (year/month/day);b) measuring location;c) measuring apparatus, type of interferometer and wavelength of laser;d) name of the measurer;e) temperature of measurement;f) thickness, shape and measurement area of sample;g) method of sample m
43、easuring system (whether or not the sample was used with the flatness correction plates);h) whether or not correction was performed for the wavefront irregularities of the optical system of the interferometer or wavefront irregularities due to the inhomogeneity of the refractive index and flatness o
44、f the flatness correction plate;4 ISO 2014 All rights reservedBS ISO 17411:2014ISO 17411:2014(E)i) value of homogeneity of the refractive index (in the case of reporting the average, the number of measurements performed);j) furthermore, a representative photograph of interference fringes of a sample
45、 should be attached where possible;k) other special conditions to be noted. ISO 2014 All rights reserved 5BS ISO 17411:2014ISO 17411:2014(E)Annex A (informative) Laser interferometerThe laser interferometer is a device that generates interference fringes by splitting the parallel rays with uniform w
46、avefronts into two with a semi-transparent plane mirror (beam splitter), and after making each ray pass through difference paths, shifts the wavefronts slightly and then superimposes them again.As examples of devices suitable for the homogeneity measurement of glass, three types of interferometers a
47、re shown below. Figures A.1 and A.2 show interferometers of the type in which a luminous flux transmits through the sample twice, and Figure A.3 shows interferometer of the type in which a luminous flux transmits through the sample once.L0IFLS H L SGPKeyG glass sampleH beam splitterL collimating len
48、sL0 imaging lensLS light sourceP plane mirrorS beam splitterIF interference fringesFigure A.1 Fizeau interferometer6 ISO 2014 All rights reservedBS ISO 17411:2014ISO 17411:2014(E)L0IFLS L1 SGP1L2P2KeyG glass sampleL0 imaging lensL1, L2 collimating lensLS light sourceP1, P2 plane mirrorS beam splitte
49、rIF interference fringesFigure A.2 Twyman-Green interferometer ISO 2014 All rights reserved 7BS ISO 17411:2014ISO 17411:2014(E)L0IFLS L1 S1GP1L2P2 S2KeyG glass sampleL1, L2 collimating lensL0 imaging lensLS light sourceP1, P2 plane mirrorS1, S2 beam splitterIF interference fringesFigure A.3 Mach-Zehnder interferometerWhen a glass sample is put into the path of one beam of these interferometers, light travels through the glass, and the wavefront irregularities (phase difference) are g
