EN ISO 11554:2003

SLOVENSKI STANDARD
SIST EN ISO 11554:2003
01-september-2003
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Optics and optical instruments - Lasers and laser-related equipment - Test methods for
laser beam power, energy and temporal characteristics (ISO 11554:2003)
Optik und optische Instrumente - Laser und Laseranlagen - Prüfverfahren für Leistung,
Energie und Kenngroßen des Zeitverhaltens von Laserstrahlen (ISO 11554:2003)
Optique et instruments d'optique - Lasers et équipements associés aux lasers -
Méthodes d'essai de la puissance et de l'énergie des faisceaux lasers et de leurs
caractéristiques temporelles (ISO 11554:2003)
Ta slovenski standard je istoveten z: EN ISO 11554:2003
ICS:
31.260 Optoelektronika, laserska Optoelectronics. Laser
oprema equipment
SIST EN ISO 11554:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 11554:2003

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SIST EN ISO 11554:2003
EUROPEAN STANDARD
EN ISO 11554
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2003
ICS 31.260 Supersedes EN ISO 11554:1998
English version
Optics and optical instruments - Lasers and laser-related
equipment - Test methods for laser beam power, energy and
temporal characteristics (ISO 11554:2003)
Optique et instruments d'optique - Lasers et équipements Optik und optische Instrumente - Laser und Laseranlagen -
associés aux lasers - Méthodes d'essai de la puissance et Prüfverfahren für Leistung, Energie und Kenngroßen des
de l'énergie des faisceaux lasers et de leurs Zeitverhaltens von Laserstrahlen (ISO 11554:2003)
caractéristiques temporelles (ISO 11554:2003)
This European Standard was approved by CEN on 24 February 2003.
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 concerning such national
standards may be obtained on application to the 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 Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,
Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United
Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36  B-1050 Brussels
© 2003 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 11554:2003 E
worldwide for CEN national Members.

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SIST EN ISO 11554:2003
EN ISO 11554:2003 (E)
CORRECTED 2003-06-25
Foreword
This document (EN ISO 11554:2003) has been prepared by Technical Committee ISO/TC 172
"Optics and optical instruments" in collaboration with Technical Committee CEN/TC 123 "Lasers
and laser-related equipment", 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 October 2003, and conflicting national
standards shall be withdrawn at the latest by October 2003.
This document supersedes EN ISO 11554:1998.
This document has been prepared under a mandate given to CEN by the European Commission
and the European Free Trade Association, and supports essential requirements of EU
Directive(s).
For relationship with EU Directive(s), see informative Annex ZB, which is an integral part of this
document.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium, Czech
Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and
the United Kingdom.
Endorsement notice
The text of ISO 11554:2003 has been approved by CEN as EN ISO 11554:2003 without any
modifications.
NOTE Normative references to International Standards are listed in Annex ZA (normative).
2

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SIST EN ISO 11554:2003
EN ISO 11554:2003 (E)
Annex ZA
(normative)
Normative references to international publications
with their relevant European publications
This European Standard incorporates by dated or undated reference, provisions from other
publications. These normative references are cited at the appropriate places in the text and the
publications are listed hereafter. For dated references, subsequent amendments to or revisions of
any of these publications apply to this European Standard only when incorporated in it by
amendment or revision. For undated references the latest edition of the publication referred to
applies (including amendments).
NOTE Where an International Publication has been modified by common modifications, indicated
by (mod.), the relevant EN/HD applies.
Publication Year Title EN Year
ISO 11145 2001 Optics and optical instruments — EN ISO 11145 2001
Lasers and laser related equipment —
Vocabulary and symbols
3

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SIST EN ISO 11554:2003
EN ISO 11554:2003 (E)
Annex ZB
(informative)
Clauses of this European Standard addressing essential requirements or
other provisions of EU Directives
This European Standard has been prepared under a mandate given to CEN by the European
Commission and the European Free Trade Association, and supports essential requirements of
the Directive 98/79/EC.
WARNING  Other requirements and other EU Directives may be applicable to the product(s)
falling within the scope of this standard.
The following clauses of this standard, as detailed in Table ZA.1, are likely to support
requirements of the EU Directive 98/79/EC.
Compliance with these clauses of this standard provides one means of conforming with the
specific essential requirements of the Directive concerned and associated EFTA regulations.
4

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SIST EN ISO 11554:2003
INTERNATIONAL ISO
STANDARD 11554
Second edition
2003-04-01
Optics and optical instruments — Lasers
and laser-related equipment — Test
methods for laser beam power, energy
and temporal characteristics
Optique et instruments d'optique — Lasers et équipements associés aux
lasers — Méthodes d'essai de la puissance et de l'énergie des faisceaux
lasers et de leurs caractéristiques temporelles

Reference number
ISO 11554:2003(E)
©
ISO 2003

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SIST EN ISO 11554:2003
ISO 11554:2003(E)
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©
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SIST EN ISO 11554:2003
ISO 11554:2003(E)
Contents Page
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and units of measurement . 2
5 Measurement principles . 2
6 Measurement configuration, test equipment and auxiliary devices . 3
6.1 Preparation . 3
6.2 Control of environmental impacts . 5
6.3 Detectors . 5
6.4 Beam-forming optics . 6
6.5 Optical attenuators . 6
7 Measurements . 6
7.1 General . 6
7.2 Power of cw lasers . 6
7.3 Power stability of cw lasers . 6
7.4 Pulse energy of pulsed lasers . 6
7.5 Energy stability of pulsed lasers . 7
7.6 Temporal pulse shape, pulse duration, rise time and peak power . 7
7.7 Pulse duration stability . 7
7.8 Pulse repetition rate . 7
8 Evaluation . 7
8.1 General . 7
8.2 Power of cw lasers . 8
8.3 Power stability of cw lasers . 8
8.4 Pulse energy of pulsed lasers . 9
8.5 Energy stability of pulsed lasers . 9
8.6 Temporal pulse shape, pulse duration, rise time and peak power . 9
8.7 Pulse duration stability . 11
8.8 Pulse repetition rate . 11
9 Test report . 11
Annex A (informative) Relative intensity noise (RIN) . 13
Bibliography . 15
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SIST EN ISO 11554:2003
ISO 11554:2003(E)
Foreword
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 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 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 International 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 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 optical instruments, Subcommittee
SC 9, Electro-optical systems.
This second edition cancels and replaces the first edition (ISO 11554:1998), which has been technically
revised.
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SIST EN ISO 11554:2003
ISO 11554:2003(E)
Introduction
The measurement of laser 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, etc. This International Standard 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 International 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.
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SIST EN ISO 11554:2003
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vi

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SIST EN ISO 11554:2003
INTERNATIONAL STANDARD ISO 11554:2003(E)
Optics and optical instruments — Lasers and laser-related
equipment — Test methods for laser beam power, energy and
temporal characteristics
1Scope
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 stability of cw-lasers, energy stability
of pulsed lasers and pulse duration stability.
The test methods given in this International Standard are to be used for the testing and characterization of
lasers.
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) applies.
ISO 11145:2001, Optics and optical instruments — Lasers and laser-related equipment — Vocabulary and
symbols
IEC 61040:1990, Power and energy measuring detectors, instruments and equipment for laser radiation
VIM, International Vocabulary of Basic and General Terms in Metrology
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11145, in the VIM, International
Vocabulary of Basic and General Terms in Metrology, as well as the following apply.
3.1
relative intensity noise
RIN
2 2
mean square of the optical power fluctuations, �∆P �, over the system bandwidth, normalized to P , the
0
square of the average power P = �P�
0
NOTE1 The spectral relative intensity noise, R(ω), is the single-sided spectral density of the power fluctuations
2
normalized to P .
0
NOTE 2 For further details, see Annex A.
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SIST EN ISO 11554:2003
ISO 11554:2003(E)
4 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 Term
∆P — Medium-term relative power fluctuation (1 min) to a 95 % confidence level
1
∆P — Long-term relative power fluctuation (60 min) to a 95 % confidence level
60
P , P W Power averaged over 0,01 s for t and over 1s for t
1 60 1 60
Mean power, averaged over 1 min and 60 min, respectively, at the operating conditions
P, WP
1 60
specified by the manufacturer
∆Q 95 %
— Relative pulse energy fluctuation to a confidence level
t 1 min
s Medium-term interval ( )
1
t 60 min
s Long-term interval ( )
60
s
— Measured standard deviation
Expanded relative uncertainty of calibration factor (k =29) corresponding to a 5%
u —
rel,k
confidence level
Expanded relative uncertainty of measurement (k =29) corresponding to a 5% confidence
u —
rel
level
T
s Pulse repetition period
τ s Rise time of laser pulse
R
∆τ τ 95 %
— Relative pulse duration fluctuation with regard to to a confidence level
H H
∆τ τ 95 %
— Relative pulse duration fluctuation with regard to to a confidence level
10 10
m
— Reading
m
— Mean value of readings
U (t)
— Detector signal
−1
R(ω) Hz
dB/Hz or Spectral relative intensity noise (spectral noise power density)
RIN dB Relative intensity noise
NOTE 1 For further details regarding 95 % confidence level, see ISO 2602.
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 [2]. In 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.
5 Measurement principles
The laser beam is directed onto 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 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.
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SIST EN ISO 11554:2003
ISO 11554:2003(E)
6 Measurement configuration, test equipment and auxiliary devices
6.1 Preparation
6.1.1 Sources with small divergence angles
The laser beam and 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 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 should 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 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. For
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 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 sphere
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 measurement 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.
6.1.3 Measurement of the RIN spectrum
As shown in Figure 2, the beam propagates through the lens, an attenuator or other lossy medium and falls on
the photodetector. The RIN R(ω) is to be determined at reference plane A, before any losses. The Poisson
component of the RIN is increased at plane B due to losses and again at plane C due to inefficiency in the
photodetection process.
NOTE For an explanation of the different components of RIN, see Annex A.
To measure RIN, an electrical splitter sends the dc photocurrent produced in a detector by a test laser to a
current meter while the ac electrical noise is amplified and then displayed on an electrical spectrum analyzer.
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 and relaxation
oscillation frequency. Consequently, variations or changes in these quantities should be minimized during the
measurement process.
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SIST EN ISO 11554:2003
ISO 11554:2003(E)
Key
1 integrating sphere
2 diffusing opaque screen
3 device being measured
4 calibrated detector
Figure 1 — Schematic arrangement for the measurement of highly divergent sources
Key
1laser
2 lens
3 attenuator or other lossy medium
4 photodetector
5 electrical splitter
6 current meter
7 pre-amplifier
8 electrical spectrum analyzer
Figure 2 — Measurement arrangement for determination of the RIN spectrum
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SIST EN ISO 11554:2003
ISO 11554:2003(E)
6.2 Control of environmental impacts
Take suitable precautions, such as mechanical and acoustical isolation of the test set-up, shielding from
extraneous radiation, temperature stabilization of the laboratory and choice of low-noise amplifiers to ensure
that the contribution to the total error is less than 10 % of the intended uncertainty. Check by performing a
background measurement such as described in Clause 7, but with the laser beam blocked from the detector
(e.g. by a beam stop in the laser resonator or close to the laser output). The value for the standard deviation
(laser beam blocked) obtained by an evaluation as described in Clause 8 shall be smaller than one tenth of the
value obtained from a measurement with the laser beam reaching the detector.
6.3 Detectors
The radiation detector shall be in accordance with IEC 61040:1990, in particular with Clauses 3 and 4.
Furthermore, the following points shall be noted.
a) Calibrated power/energy meter:
— any wavelength dependency, non-linearity or non-uniformity of the detector or the electronic device shall
be minimized or corrected by use of a calibration procedure;
— for measuring beams with large divergence, an integrating sphere detector should be used to assure
collection of all the emitted radiation. The direct measurement (i.e. using a planar-surface detector
without an integrating sphere) can only be used when it has been determined that the sensitivity of the
◦
detector is uniform and independent on incident angles to within 5 and the entire beam reaches the
photosensitive surface of the photodetector;
— detectors used for all quantitative measurements shall be calibrated with traceability back to relevant
national standards.
b) Integrating sphere (used together with a calibrated power/energy meter when measuring sources with large
divergence angles sources):
— the sphere surface shall be large compared to the device being measured, the screen and the
apertures;
— the area of the sphere openings shall be small compared to the overall surface area of the sphere;
— the inner surface of the sphere and screen shall have a diffusing coating with a high uniform reflectance
(0,9 minimum);
— the total losses through the sphere ports shall be less than 5%;
— the sphere and detector assembly shall be calibrated with traceability back to relevant national
standards;
— change in peak-emission wavelength and flux due to power dissipation shall be taken into account.
c) Time resolving detector:
— it shall be confirmed, from the manufacturer's data or by measurement, that the output quantity of the
detector (e.g. the voltage) is linearly dependent on the input quantity (laser power). Any wavelength
dependency, non-linearity or non-uniformity of the detector and any associated electronic devices shall
be minimized or corrected by use of a calibration procedure;
— the electrical frequency bandwidth of the detector, including the bandwidth of all associated electronics,
shall reproduce the temporal laser pulse shape correctly. This International Standard cannot be applied
to measure pulses faster than the capability of the detection system.
When measuring pulse shape characteristics (e.g. peak power, pulse width, etc.), the risetime of the detector
(including the amplifier and other associated electronics) being used shall be less than one tenth of the risetime
of the pulses to be measured.
Care shall be taken to ascertain the damage thresholds (for irradiance, radiant exposure, power and energy) of
the detector surface and all optical elements located between the laser and the detector (e.g. polarizer,
attenuator) to ensure they are not exceeded by the incident laser beam.
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SIST EN ISO 11554:2003
ISO 11554:2003(E)
6.4 Beam-forming optics
If the cross-section of the beam is greater than the detector area, a suitable optical system shall be used to
image the area of the cross-section of the laser beam onto the detector surface.
Optics shall be selected appropriate to the wavelength of the laser radiation being measured.
Absorption/reflection/ clipping/diffraction losses shall be measured and accounted for in all measurements. The
laser radiation polarization state shall be accounted for if polarization-dependent reflections are present.
6.5 Optical attenuators
When necessary, an attenuator can be used to reduce the laser power density at the surface of the detector.
Optical attenuators shall be used when the output laser power or power density exceeds either the detector's
working (linear) range or its damage threshold. Any wavelength dependency, polarization dependency, angular
dependency, non-linearity, or spatial non-uniformity of the optical attenuator shall be minimized or corrected by
use of a calibration procedure.
7 Measurements
7.1 General
If not otherwise stated, carry out all measurements 10 times, with intervening background measurements.
Before beginning the measurements, the laser shall w
...