prEN ISO 11670

SLOVENSKI STANDARD
01-julij-2025
Laserji in laserska oprema - Preskusne metode za parametre laserskega žarka -
Prostorska stabilnost žarka (ISO/DIS 11670:2025)
Lasers and laser-related equipment - Test methods for laser beam parameters - Beam
spatial stability (ISO/DIS 11670:2025)
Laser und Laseranlagen - Prüfverfahren für Laserstrahlparameter - Strahllagestabilität
(ISO/DIS 11670:2025)
Lasers et équipements associés aux lasers - Méthodes d'essai des paramètres du
faisceau laser - Stabilité de visée du faisceau (ISO/DIS 11670:2025)
Ta slovenski standard je istoveten z: prEN ISO 11670
ICS:
31.260 Optoelektronika, laserska Optoelectronics. Laser
oprema equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
International
Standard
ISO/DIS 11670
ISO/TC 172/SC 9
Lasers and laser-related
Secretariat: DIN
equipment — Test methods for
Voting begins on:
laser beam parameters — Beam
2025-05-09
spatial stability
Voting terminates on:
ICS: 31.260
2025-08-01
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
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This document is circulated as received from the committee secretariat.
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RECIPIENTS OF THIS DRAFT ARE INVITED
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NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Reference number
ISO/DIS 11670:2025(en)
DRAFT
ISO/DIS 11670:2025(en)
International
Standard
ISO/DIS 11670
ISO/TC 172/SC 9
Lasers and laser-related
Secretariat: DIN
equipment — Test methods for
Voting begins on:
laser beam parameters — Beam
spatial stability
Voting terminates on:
ICS: 31.260
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2025
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
BE CONSIDERED IN THE LIGHT OF THEIR
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Published in Switzerland Reference number
ISO/DIS 11670:2025(en)
ii
ISO/DIS 11670:2025(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Coordinate system . 4
5 Test principles . 5
5.1 Position fluctuation widths .5
5.2 Angular fluctuation widths .5
6 Measurement arrangement, test equipment and auxiliary devices . 5
6.1 Preparation .5
6.2 Control of environment .6
6.3 Detection system .6
6.4 Optical attenuators, beam splitters, imaging optics, focusing elements .6
6.5 Calibration of detector sensitivity to lateral beam displacement .7
7 Test procedures . 7
7.1 General .7
7.2 Position fluctuation widths .7
7.3 Angular fluctuation widths .8
8 Evaluation . 9
8.1 Position fluctuation width .9
8.2 Angular fluctuation widths .9
9 Test report . 9

iii
ISO/DIS 11670:2025(en)
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.
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 needed 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 patent
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 in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 172, Optics and photonics, Subcommittee SC 9,
Laser and electro-optical systems.
This third edition cancels and replaces the second edition (ISO 11670:2003), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— Title, Terms and definitions and main text were revised using the new term “Beam positional stability”
— Rarely used terms and definitions have been removed
— New Figures 1 – 3 were included;
— standard was updated to new normative references.
— Annexes A and B have been removed
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
ISO/DIS 11670:2025(en)
Introduction
The centre of a laser beam in a plane perpendicular to the direction of propagation is defined as the centroid or
first-order spatial moment of the irradiance (fluence) distribution. The current propagation axis of a beam is
then the straight line connecting two centroids measured at two different planes simultaneously in a uniform,
homogeneous medium. Beam axis instabilities may be characterized by transverse position displacements
and by angular direction displacements that are either monotonic, periodic, or stochastic in time.
The magnitude of the transverse position fluctuations in a plane is quantified by the position displacement
width. A smaller position displacement width is equivalent to greater beam positional stability.
The magnitude of the angular fluctuations in a plane is quantified by the angular fluctuation width. A
smaller angular fluctuation width is equivalent to greater beam directional stability.
If the magnitude of the transverse fluctuations in an application plane is not significantly smaller than the
(instantaneous) beam diameter there, then, at longer exposure times, the laser radiation will be distributed
over a larger area as would be expected based on the beam diameter alone, leading to an increased effective
beam diameter and reducing the time-averaged energy density.
In the same manner angular fluctuations can increase the effective divergence of a laser beam.
The positional stability of the beam and the angular stability of the beam are referred to together as the
spatial stability of the beam.
This document provides general principles for the measurement of the positional und angular beam stability.
In addition, definitions of terminology and symbols to be used in referring to them are provided.

v
DRAFT International Standard ISO/DIS 11670:2025(en)
Lasers and laser-related equipment — Test methods for laser
beam parameters — Beam spatial stability
1 Scope
This document specifies methods for determining laser beam positional as well as angular stability. The test
methods given in this document are intended to be used for the testing and characterization of lasers.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements 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, Optics and optical instruments — Lasers and laser-related equipment — Vocabulary and symbols
ISO 11146-1, Lasers and laser-related equipment — Test methods for laser beam widths, divergence angles and
beam propagation ratios — Part 1: Stigmatic and simple astigmatic beams
EN 61040:1990, Power and energy measuring detectors, instruments and equipment for laser radiation
3 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 61040, ISO 11145 and ISO 11146-1
and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
momentary beam centroid coordinates
xz() , yz()
first order moments of the momentary irradiance (fluence) of a fluctuating beam at location z measured
along the laboratory coordinates x and y of a beam propagating approximately in z direction
∫∫xE⋅ ()xy,,zx⋅ddy
xz =
()
∫∫Ex,,yz ⋅ddxy
()
∫∫ yE⋅ ()xy,,zx⋅ddy
yz() =
∫∫Ex(),,yz ⋅ddxy
Note 1 to entry: In general, since fluctuations are assumed, the irradiance (fluence) distribution as well as the
momentary beam centroid coordinates will vary from moment to moment (i.e., from measurement to measurement).
3.2
distribution of momentary beam centroid coordinates
xz() , yz()
ii
set of momentary beam centroid coordinates measured at different moments (times) at the same location z
Note 1 to entry: If N measurements have been made, the index i runs from 1 to N.

ISO/DIS 11670:2025(en)
3.3
mean beam centroid coordinates
xz() ,yz()
MM
arithmetical mean of a distribution of momentary beam centroid coordinates at location z
N
xz()= xz()
M i
∑
N
i=1
N
yz()= yz()
M ∑ i
N
i=1
Note 1 to entry: If the number of measurements N of each set is sufficiently large, different sets measured on the same
beam at the same location z will results in approximately the same mean beam centroid coordinates. Thus, the mean
beam centroid coordinates may be considered as the (stable) beam centroid position at location z.
3.4
momentary position displacement
δδδxz ,δ yz
() ()
deviation of the momentary beam centroid coordinates from the mean beam centroid coordinates at location z
δxz()=xz()−xz()
M
δyz = yz − yz
() () ()
M
3.5
position displacement distributions
δδδxz() ,δ yz()
ii
set of momentary position displacements at location z
δxz =xz −xz
() () ()
ii M
δ yz()= yz()− yz()
ii M
Note 1 to entry: If N measurements have been made, the index i runs from 1 to N.
Note 2 to entry: If the number of measurements N is large enough, two independently measured position displacement
distributions of the same beam measured at the same location z, will have approximal the same extent, although the
distributions may not be identical.
3.6
position fluctuation widths
ΔΔΔxz() ,Δy()z
quantitative measures for the extent of a measured position displacement distribution at location z
N
δxz()
i
∑
i=1
Δxz =4
()
N−1
N
δ yz()
∑ i
i=1
Δy()z =4
N−1
Note 1 to entry: In general, the position fluctuation widths of a real beam will vary under free propagation through a
homogeneous medium. Thus, there will be indeed a dependency on the location z (in contrast to the angular fluctuation
width, see clause 3.12).
...