1、 Reference numberISO 11554:2006(E)ISO 2006INTERNATIONAL STANDARD ISO11554Third edition2006-05-01Optics and photonics Lasers and laser-related equipment Test methods for laser beam power, energy and temporal characteristics Optique et photonique Lasers et quipements associs aux lasers Mthodes dessai
2、de la puissance et de lnergie des faisceaux lasers et de leurs caractristiques temporelles ISO 11554:2006(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which
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7、ISO 2006 All rights reservedISO 11554:2006(E) ISO 2006 All rights reserved iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Symbols and units of measurement. 2 5 Measurement principles. 3 6 Measurement configuration, test equipment and a
8、uxiliary devices . 3 6.1 Preparation 3 6.2 Control of environmental impacts 6 6.3 Detectors . 6 6.4 Beam-forming optics 7 6.5 Optical attenuators . 7 7 Measurements. 7 7.1 General. 7 7.2 Power of cw lasers 7 7.3 Power stability of cw lasers. 8 7.4 Pulse energy of pulsed lasers . 8 7.5 Energy stabili
9、ty of pulsed lasers. 8 7.6 Temporal pulse shape, pulse duration, rise time, fall time and peak power 8 7.7 Pulse duration stability 8 7.8 Pulse repetition rate . 8 7.9 Small signal cut-off frequency 9 8 Evaluation 9 8.1 General. 9 8.2 Power of cw lasers 9 8.3 Power stability of cw lasers. 10 8.4 Pul
10、se energy of pulsed lasers . 10 8.5 Energy stability of pulsed lasers. 10 8.6 Temporal pulse shape, pulse duration, rise time, fall time and peak power 10 8.7 Pulse duration stability 13 8.8 Pulse repetition rate . 13 8.9 Small signal cut-off frequency 13 9 Test Report 13 Annex A (informative) Relat
11、ive intensity noise (RIN) . 16 Bibliography . 18 ISO 11554:2006(E) iv ISO 2006 All rights reservedForeword 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 ca
12、rried out through ISO technical 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
13、. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters 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 Intern
14、ational Standards. Draft International Standards adopted by the technical committees are circulated 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
15、 elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 11554 was prepared by Technical Committee ISO/TC 172, Optics and photonics, Subcommittee SC 9, Electro-optical systems. This third edition cancels and
16、replaces the second edition (ISO 11554:2003), which has been technically revised. For the purposes of this International Standard, the CEN annex regarding fulfilment of European Council Directives has been removed. ISO 11554:2006(E) ISO 2006 All rights reserved vIntroduction The measurement of laser
17、 power (energy for pulsed lasers) is a common type of measurement performed by laser manufacturers and users. Power (energy) measurements are needed for laser safety classification, stability specifications, maximum laser output specifications, damage avoidance, specific application requirements, et
18、c. This document provides guidance on performing laser power (energy) measurements as applied to stability characterization. The stability criteria are described for various temporal regions (e.g., short-term, medium-term and long-term) and provide methods to quantify these specifications. This Inte
19、rnational Standard also covers pulse measurements where detector response speed can be critically important when analysing pulse shape or peak power of short pulses. To standardize reporting of power (energy) measurement results, a report template is also included. This International Standard is a T
20、ype B standard as stated in ISO 12100-1. The provisions of this International standard may be supplemented or modified by a Type C standard. Note that for machines which are covered by the scope of a Type C standard and which have been designed and built according to the provisions of that standard,
21、 the provisions of that Type C standard take precedence over the provisions of this Type B standard. INTERNATIONAL STANDARD ISO 11554:2006(E) ISO 2006 All rights reserved 1Optics and photonics Lasers and laser-related equipment Test methods for laser beam power, energy and temporal characteristics 1
22、 Scope This International Standard specifies test methods for determining the power and energy of continuous-wave and pulsed laser beams, as well as their temporal characteristics of pulse shape, pulse duration and pulse repetition rate. Test and evaluation methods are also given for the power stabi
23、lity of cw-lasers, energy stability of pulsed lasers and pulse duration stability. The test methods given in this International Standard are used for the testing and characterization of lasers. 2 Normative references The following referenced documents are indispensable for the application of this do
24、cument. For dated references, only the edition cited applies. For undated references, the last edition of the referenced document (including any amendments) applies. ISO 11145:2006, Optics and optical instruments Lasers and laser-related equipment Vocabulary and symbols IEC 61040:1990, Power and ene
25、rgy measuring detectors, instruments and equipment for laser radiation International vocabulary of basic and general terms in metrology (VIM). BIPM, IEC, IFCC, ISO, IUPAC, IUPAP, OIML, 2nd ed. 1993 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 1114
26、5, in the VIM and the following apply. 3.1 relative intensity noise RIN R( f ) single-sided spectral density of the power fluctuations normalized to the square of the average power as a function of the frequency f NOTE 1 The relative intensity noise R( f ) or RIN as defined above is explicitly spoke
27、n of as the “relative intensity noise spectral density”, but usually simply referred to as RIN. NOTE 2 For further details, see Annex A. 3.2 small signal cut-off frequency fcfrequency at which the laser power output modulation drops to half the value obtained at low frequencies when applying small,
28、constant input power modulation and increasing the frequency ISO 11554:2006(E) 2 ISO 2006 All rights reserved4 Symbols and units of measurement The symbols and units specified in ISO 11145 and in Table 1 are used in this International Standard. Table 1 Symbols and units of measurement Symbol Unit Te
29、rm f Hz Frequency fcHz Small signal cut-off frequency f1, f2 Hz Frequency range for which the relative intensity noise R( f ) is given k 1 Coverage factor for the determination of uncertainty m 1 Reading m 1 Mean value of readings P W Power averaged over the sampling period P W Mean power, averaged
30、over the measurement period at the operating conditions specified by the manufacturer P 1 Relative power fluctuation to a 95 % confidence level for the appropriate sampling period P (1 s) and/or P (1 ms) and/or P (0,1 s) and/or P (1 s) Q J Mean pulse energy Q 1 Relative pulse energy fluctuation to a
31、 95 % confidence level R( f ) Hz1or dB/Hz Relative intensity noise, RIN S(t) 1 Detector signal s 1 Measured standard deviation T s Pulse repetition period t s Measurement period Urel1 Expanded relative uncertainty corresponding to a 95 % confidence level (coverage factor k = 2) Urel(C) 1 Expanded re
32、lative uncertainty of calibration corresponding to a 95 % confidence level (coverage factor k = 2) Fs Fall time of laser pulse H1 Relative pulse duration fluctuation with regard to Hto a 95 % confidence level Rs Rise time of laser pulse 101 Relative pulse duration fluctuation with regard to 10to a 9
33、5 % confidence level NOTE 1 For further details regarding 95 % confidence level see ISO 2602 1. NOTE 2 The expanded uncertainty is obtained by multiplying the standard uncertainty by a coverage factor k = 2. It is determined according to the Guide to the Expression of Uncertainty in Measurement 3. I
34、n general, with this coverage factor, the value of the measurand lies with a probability of approximately 95 % within the interval defined by the expanded uncertainty. NOTE 3 R( f ) expressed in dB/Hz equals 10 lg R( f ) with R( f ) given in Hz1. ISO 11554:2006(E) ISO 2006 All rights reserved 35 Mea
35、surement principles The laser beam is directed on to the detector surface to produce a signal with amplitude proportional to the power or energy of the laser. The amplitude versus time is measured. Radiation emitted by sources with large divergence angles is collected by an integrating sphere. Beam
36、forming and attenuation devices may be used when appropriate. The evaluation method depends on the parameter to be determined and is described in Clause 8. 6 Measurement configuration, test equipment and auxiliary devices 6.1 Preparation 6.1.1 Sources with small divergence angles The laser beam and
37、the optical axis of the measuring system shall be coaxial. Select the diameter (cross-section) of the optical system such that it accommodates the entire cross-section of the laser beam and so that clipping or diffraction loss is smaller than 10 % of the intended measurement uncertainty. Arrange an
38、optical axis so that it is coaxial with the laser beam to be measured. Suitable optical alignment devices are available for this purpose (e.g., aligning lasers or steering mirrors). Mount the attenuators or beam-forming optics such that the optical axis runs through the geometrical centres. Care sho
39、uld be exercised to avoid systematic errors. NOTE 1 Reflections, external ambient light, thermal radiation and air currents are all potential sources of errors. After the initial preparation is completed, make an evaluation to determine if the entire laser beam reaches the detector surface. For this
40、 determination, apertures of different diameters can be introduced into the beam path in front of each optical component. Reduce the aperture size until the output signal has been reduced by 5 %. This aperture should have a diameter at least 20 % smaller than the aperture of the optical component. F
41、or divergent beams, the aperture should be placed immediately in front of the detector to assure total beam capture. NOTE 2 Remove these apertures before performing the power (energy) measurements described in Clause 7. 6.1.2 Sources with large divergence angles The radiation emitted by sources with
42、 large divergence angles shall be collected by an integrating sphere. The collected radiation is subjected to multiple reflections from the wall of the integrating sphere; this leads to a uniform irradiance of the surface proportional to the collected flux. A detector located in the wall of the sphe
43、re measures this irradiance. An opaque screen shields the detector from the direct radiation of the device being measured. The emitting device is positioned at or near the entrance of the integrating sphere, so that no direct radiation will reach the detector. Figure 1 shows an integrating sphere me
44、asurement configuration for a small emitting source positioned inside the integrating sphere. Large-sized sources should, of course, be positioned outside the sphere but close enough to the input aperture so that all emitted radiation enters the sphere. ISO 11554:2006(E) 4 ISO 2006 All rights reserv
45、edKey 1 integrating sphere 3 device being measured 2 diffusing opaque screen 4 detector Figure 1 Schematic arrangement for the measurement of highly divergent sources 6.1.3 RIN measurement The measuring arrangement for determination of the RIN is shown in Figure 2. The beam propagates through the le
46、ns, an attenuator or other lossy medium, and falls on the detector. When adjusting the measuring arrangement, feedback of the output power into the laser shall be minimized to avoid measurement errors. The RIN, R( f ) is determined at reference plane A, before any losses. The Poisson component of th
47、e RIN is increased at plane B due to losses, and again at plane C due to inefficiency in the detection process. NOTE For an explanation of the different components of RIN, see Annex A. To measure RIN, an electrical splitter sends the dc detector signal produced by a test laser to a meter while the a
48、c electrical noise is amplified and then displayed on an electrical spectrum analyser. RIN depends on numerous quantities, the primary ones being: frequency; output power; temperature; modulation frequency; time delay and magnitude of optical feedback; mode-suppression ratio; relaxation oscillation
49、frequency. Consequently, variations or changes in these quantities should be minimized during the measurement process. ISO 11554:2006(E) ISO 2006 All rights reserved 56.1.4 Measurement of small signal cut-off frequency For determination of the small signal cut-off frequency, fc, of lasers, the laser is modulated as described in 7.9 and the ac output power measured. Figure 3 shows the basic measurement arrangement for the case of diode lasers. When adjusting the measuring arrangement,
