kSIST FprEN ISO 13696:2022
(Main)Optics and photonics - Test method for total scattering by optical components (ISO/FDIS 13696:2022)
Optics and photonics - Test method for total scattering by optical components (ISO/FDIS 13696:2022)
Optik und Photonik - Bestimmung von totaler Streustrahlung, hervorgerufen durch optische Komponenten (ISO/FDIS 13696:2022)
Dieses Dokument legt ein Prüfverfahren für die Bestimmung der Gesamtstreuung von beschichteten und unbeschichteten optischen Oberflächen fest. Verfahren zur Messung der Beiträge der Vorwärts- und Rückwärtsstreuung zur Gesamtstreuung von optischen Komponenten werden angegeben.
Dieses Dokument bezieht sich auf beschichtete und unbeschichtete optische Komponenten mit optischen Oberflächen, die einen Krümmungsradius von mehr als 10 m besitzen. Die von diesem Dokument abgedeckten Messwellenlängenbereiche reichen vom Ultraviolettbereich oberhalb von 250 nm bis in den infraroten Spektralbereich unterhalb von 15 μm. Für Messungen im tiefen Ultraviolettbereich zwischen 190 nm und 250 nm müssen spezifische Verfahren in Betracht gezogen werden, die in diesem Dokument beschrieben sind. In der Regel kann die optische Streuung für Wellenlängen oberhalb 15 μm als vernachlässigbar betrachtet werden.
Optique et photonique - Méthodes d’essai du rayonnement diffusé par les composants optiques (ISO/FDIS 13696:2022)
Optika in optični instrumenti - Preskusne metode za sevanje, razpršeno z optičnimi komponentami (ISO/FDIS 13696:2022)
General Information
RELATIONS
Standards Content (sample)
SLOVENSKI STANDARD
oSIST prEN ISO 13696:2021
01-junij-2021
Optika in optični instrumenti - Preskusne metode za sevanje, razpršeno z
optičnimi komponentami (ISO/DIS 13696:2021)
Optics and photonics - Test method for total scattering by optical components (ISO/DIS
13696:2021)Optik und Photonik - Bestimmung von Streustrahlung, hervorgerufen durch optische
Komponenten (ISO/DIS 13696:2021)
Optique et photonique - Méthodes d’essai du rayonnement diffusé par les composants
optiques (ISO/DIS 13696:2021)Ta slovenski standard je istoveten z: prEN ISO 13696
ICS:
31.260 Optoelektronika, laserska Optoelectronics. Laser
oprema equipment
oSIST prEN ISO 13696:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN ISO 13696:2021
DRAFT INTERNATIONAL STANDARD
ISO/DIS 13696
ISO/TC 172/SC 9 Secretariat: DIN
Voting begins on: Voting terminates on:
2021-04-08 2021-07-01
Optics and photonics — Test method for total scattering by
optical components
Optique et photonique — Méthodes d'essai du rayonnement diffusé par les composants optiques
ICS: 31.260THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 13696:2021(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. ISO 2021
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oSIST prEN ISO 13696:2021
ISO/DIS 13696:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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ii © ISO 2021 – All rights reserved
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oSIST prEN ISO 13696:2021
ISO/DIS 13696:2021(E)
Contents Page
Foreword ........................................................................................................................................................................................................................................iv
Introduction ................................................................................................................................................................................................................................vi
1 Scope ................................................................................................................................................................................................................................. 1
2 Normative references ...................................................................................................................................................................................... 1
3 Terms, definitions and symbols ............................................................................................................................................................ 1
3.1 Terms and definitions ....................................................................................................................................................................... 1
3.2 Symbols and units of measure ................................................................................................................................................... 3
4 Test method ............................................................................................................................................................................................................... 3
4.1 Principle ........................................................................................................................................................................................................ 3
4.2 Measurement arrangement and test equipment ....................................................................................................... 3
4.2.1 General...................................................................................................................................................................................... 3
4.2.2 Radiation source .............................................................................................................................................................. 4
4.2.3 Beam preparation system ........................................................................................................................................ 4
4.2.4 Integrating sphere .......................................................................................................................................................... 5
4.2.5 Detection system.............................................................................................................................................................. 6
4.2.6 Specimen holder .............................................................................................................................................................. 6
4.3 Arrangement with high sensitivity ........................................................................................................................................ 6
4.4 Preparation of specimens .............................................................................................................................................................. 7
5 Procedure..................................................................................................................................................................................................................... 7
5.1 General ........................................................................................................................................................................................................... 7
5.2 Alignment procedure ......................................................................................................................................................................... 8
5.2.1 General...................................................................................................................................................................................... 8
5.2.2 Alignment of the beam ........................................................................................................................................... ..... 8
5.2.3 Alignment of the specimen ..................................................................................................................................... 8
5.3 Measurement procedure ................................................................................................................................................................ 8
6 Evaluation .................................................................................................................................................................................................................... 9
6.1 Determination of the total scattering value ................................................................................................................... 9
6.2 Error budget ...........................................................................................................................................................................................12
7 Test report ................................................................................................................................................................................................................12
Annex A (informative) Set-up with a Coblentz hemisphere ......................................................................................................14
Annex B (informative) Example of test report .........................................................................................................................................17
Annex C (informative) Statistical evaluation example ....................................................................................................................21
Annex D (informative) Example for selection of spacing .............................................................................................................26
Annex E (informative) Alternative method for calibrating total scatter measurements using
a calcium fluoride diffuser disk .........................................................................................................................................................29
Bibliography .............................................................................................................................................................................................................................31
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oSIST prEN ISO 13696:2021
ISO/DIS 13696:2021(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.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 on 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 the following URL: 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 second edition cancels and replaces the first edition (ISO 13696:2002), which has been technically
revised.The main changes compared to the previous edition are as follows:
Scope: measurement range outlined in more detail and limited to 250 nm. For measurements in the
deep ultraviolet between 190 nm to 250 nm, specific methods have to be considered and are described.
3.1.6: additional Note 2 inserted for high volume scattering of the specimen3.1.6: additional Note 3 inserted for comprehensive illustration of the term total scattering
3.1.7: Note extended concerning diffuse reflectance standard for wavelengths below 250 nm down to
the deep ultraviolet3.2: New symbols for total scattering (σ ), forward scattering (τ ), and backward scattering (ρ ) in
TS TS TSTable 1.
Figure 1 and 4.2.5: lock-in amplifier optional. For fast data acquisition modules, no Lock-in technique
may be necessary4.2.2: calibration of the monitor detector is not necessary. The power at the sample surface shall be
measured by a calibrated detector.4.2.4: additional Note 1 inserted concerning aging of the diffuse reflecting material on the inner walls
of the sphere.4.2.5: additional Note inserted concerning optional components for a phase sensitive detection scheme
with lock-in amplifier.iv © ISO 2021 – All rights reserved
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oSIST prEN ISO 13696:2021
ISO/DIS 13696:2021(E)
5.3: change of measurement sequence starting with power measurement calibration procedure, and
determination of the signal of the unloaded sphere prior to the measurement of the specimen.
6.1: additional Note 3 inserted concerning specimens larger than the diffuse reflectance standard for
the case of single point measurements.6.1: adaptation of Formulae (1, 2) and (5) to (8) (in the denominator V r was adapted to V )
ci c1 N 2
Formula (C2) reads σρ= Mr−
sT∑ SiS,sc
i=1
N−1
6.1: additional Note 6 inserted concerning calibration samples with arbitrary diffuse reflectance
Annex E: additional Annex inserted concerning alternative method for calibrating total scatter
measurements using a calcium fluoride diffuser diskBibliography: ISO 31-6:1992 was replaced by current version ISO 80000-7, same for ISO 11146 with
ISO 11146-1 and −2, ISO 11554 and ISO 12005 no longer cited dated. Also replacement of former
citations [5] and [6] by latest edition of SEMI F1048Any 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© ISO 2021 – All rights reserved v
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oSIST prEN ISO 13696:2021
ISO/DIS 13696:2021(E)
Introduction
In most applications, scattering in optical components reduces the efficiency and deteriorates the
image-forming quality of optical systems. Scattering is predominantly produced by imperfections of
the coatings and the optical surfaces of the components. Common surface features, which contribute
to optical scattering, are imperfections of substrates, thin films and interfaces, surface and interface
roughness, or contamination and scratches. These imperfections deflect a fraction of the incident
radiation from the specular path. The spatial distribution of this scattered radiation is dependent on
the wavelength of the incident radiation and on the individual optical properties of the component. For
most applications in laser technology and optics, the amount of total loss produced by scattering is a
useful quality criterion of an optical component.This document describes a testing procedure for the corresponding quantity, the total scattering (σ )
value, which is defined by the measured values of backward scattering and forward scattering. The
measurement principle described in this document is based on an Ulbricht sphere as the integrating
element for scattered radiation. An alternative apparatus with a Coblentz hemisphere, which is also
frequently employed for collecting scattered light, is described in Annex A.Annexes A to E of this document are for information only.
vi © ISO 2021 – All rights reserved
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oSIST prEN ISO 13696:2021
DRAFT INTERNATIONAL STANDARD ISO/DIS 13696:2021(E)
Optics and photonics — Test method for total scattering by
optical components
1 Scope
This document specifies procedures for the determination of the total scattering by coated and uncoated
optical surfaces. Procedures are given for measuring the contributions of the forward scattering and
backward scattering to the total scattering of an optical component.This document applies to coated and uncoated optical components with optical surfaces that have a
radius of curvature of more than 10 m. Measurement wavelengths covered by this document range
from the ultraviolet above 250 nm to the infrared spectral region below 15 µm. For measurements
in the deep ultraviolet between 190 nm to 250 nm, specific methods have to be considered and are
described. Generally, optical scattering is considered as neglectable for wavelengths above 15 µm.
2 Normative referencesThe 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 photonics — Lasers and laser-related equipment — Vocabulary and symbols
ISO 14644-1:2015, Cleanrooms and associated controlled environments — Part 1: Classification of air
cleanliness by particle concentration3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 11145 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/
3.1.1
scattered radiation
fraction of the incident radiation that is deflected from the specular optical path
3.1.2front surface
optical surface that interacts first with the incident radiation
3.1.3
rear surface
surface that interacts last with the transmitted radiation
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oSIST prEN ISO 13696:2021
ISO/DIS 13696:2021(E)
3.1.4
backward scattering
fraction of radiation scattered by the optical component into the backward halfspace
Note 1 to entry: Backward halfspace is defined by the halfspace that contains the incident beam impinging upon
the component and that is limited by a plane containing the front surface of the optical component.
3.1.5forward scattering
fraction of radiation scattered by the optical component into the forward halfspace
Note 1 to entry: Forward halfspace is defined by the halfspace that contains the beam transmitted by the
component and that is limited by a plane containing the rear surface of the optical component.
3.1.6total scattering
ratio of the total power generated by all contributions of scattered radiation into the forward or the
backward halfspace to the power of the incident radiationNote 1 to entry: The halfspace in which the scattering is measured should be clearly stated.
Note 2 to entry: The sum of the measured forward and backward scattering does not include the contribution of
the bulk material in the optical component. In case the volume scattering of the component is not negligible, the
total scatter losses may exceed the sum of forward and backward scattering.Note 3 to entry: Total scattering is equal to forward or backward scattering, and is neither the sum of both nor
the sum of all scattering contributions.3.1.7
diffuse reflectance standard
diffuse reflector with known total reflectance
Note 1 to entry: Commonly used diffuse reflectance standards are fabricated from barium sulfate or
polytetrafluoroethylene powders (see Table 2). The total reflectance of reflectors freshly prepared from these
materials is typically greater than 0,98 in the spectral range given in Table 2, and it can be considered as a
100 % reflectance standard. For increasing the accuracy, diffuse reflectance standards with lower reflectance
values can be realized by mixtures of polytetrafluoroethylene powder and powders of absorbing materials.
(See Reference [6] in the Bibliography.) Further concepts for diffuse reflectance standards include optical
surfaces with specially prepared microstructures, metal-coated diffusers or diffuse transparent reference
samples. A versatile method on the basis of a calcium fluoride diffuser disk for the wavelength range from 250 nm
down to the deep ultraviolet is described in Annex E.3.1.8
range of acceptance angle
range from the minimum to the maximum angle with respect to the reflected or transmitted beam that
can be collected by the integrating element3.1.9
angle of polarization
angle between the major axis of the instantaneous polarization ellipse of the incident radiation and the
plane of incidenceNote 1 to entry: For non-normal incidence, the plane of incidence is defined by the plane which contains the
direction of propagation of the incident radiation and the normal at the point of incidence.
Note 2 to entry: The angle of polarization, γ, is identical to the azimuth, Φ (according to ISO 12005) , if the
reference axis is located in the plane of incidence.2 © ISO 2021 – All rights reserved
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oSIST prEN ISO 13696:2021
ISO/DIS 13696:2021(E)
3.2 Symbols and units of measure
Table 1 — Symbols and units of measure
Symbol Term Unit
λ Wavelength nm
α Angle of incidence degrees
γ Angle of polarization degrees
d Beam diameter on the surface of the specimen mm
P Power of the incident radiation W
inc
P Total power, backward scattered radiation W
bac
P Total power, forward scattered radiation W
for
σ Total scattering
ρ Backward scattering
τ Forward scattering
V Detector signal for the specimen, backward scattering V
s,bac
V Detector signal for the specimen, forward scattering V
s,for
V Detector signal, diffuse reflectance standard V
V Detector signal, test ports open V
τ Transmittance of specimen at wavelength, λ
ρ Reflectance of specimen at wavelength, λ
r Sample position mm
N Number of test sites per surface
4 Test method
4.1 Principle
The fundamental principle (see Figure 1) of the measurement apparatus is based on the collection
and integration of the scattered radiation. For this purpose, a hollow sphere with a diffusely
reflecting coating on the inner surface (Ulbricht sphere) is employed. Beam ports are necessary for
the transmission of the test beam and the specularly reflected beam through the wall of the sphere.
The sample is attached to one of these ports forming a part of the inner surface of the sphere. For
the measurement of the backward scattering, the specimen is located at the exit port. The forward
scattering is determined by mounting the specimen to the entrance port. The scattered radiation is
integrated by the sphere and measured by a suitable detector, which is attached to an additional port
at an appropriate position. A diffuse reflectance standard is used for calibration of the detector signal.
4.2 Measurement arrangement and test equipment4.2.1 General
The measurement facility employed for the determination of the total scattering is divided into four
functional sections, which are described in detail below. One functional section consists of the radiation
source and the beam preparation system. Two different components are defined by the integration and
detection of the scattered radiation. Another section is formed by the sample holder and its optional
accessories.© ISO 2021 – All rights reserved 3
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oSIST prEN ISO 13696:2021
ISO/DIS 13696:2021(E)
Key
1 Radiation source 11 Exit port
2 Chopper 12 Beam stop
3 Spatial filter 13 Sample
4 Telescope 14 Radiation baffles
5 Beam splitter 15 Detector, diffuser
6 Power detector 16 Beam stop
7 Power meter 17 Chopper signal
8 Entrance port 18 Lock-in amplifier (optional)
9 Ulbricht sphere 19 Detector signal, V
10 Coating
Figure 1 — Schematic arrangement for the measurement of total scattering
(configuration for backward scattering with phase sensitive detection scheme)
4.2.2 Radiation source
As radiation sources, lasers are preferred because of their excellent beam quality and the high power
density achievable on the sample surface. For special applications involving the wavelength dependence
of scattering, different conventional radiation sources may be used in conjunction with spectral filters
or monochromators. Different types of discharge, arc or tungsten lamps are suitable for wavelength-
resolved total scatter measurements.The temporal power variation of the radiation source shall be measured and documented. For this
purpose, a beam splitter and a monitor detector are installed. The power at the sample surface shall be
measured by a calibrated detector for both test locations at the entrance and exit port of the integrating
element.4.2.3 Beam preparation system
The beam preparation system consists of a spatial filter and additional apertures, if necessary, for
cleaning the beam. For measurements involving conventional radiation sources, additional optical
elements are required for the shaping and collimation of the beam. The beam diameter, d , at the surface
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oSIST prEN ISO 13696:2021
ISO/DIS 13696:2021(E)
of the specimen shall be greater than 0,4 mm. No radiation power shall be present in the collimated
beam profile beyond radial positions exceeding the beam radius by a factor of 5.NOTE 1 The behaviour of the measured total scatter value may be dependent on the beam diameter and the
beam profile (see Annex D).On the sample surface, the beam profile shall be smooth without local power density values exceeding
the average power density within the beam diameter, d , by a factor of three. For measurement systems
with a laser as the radiation source, a TEM -operation with a diffraction-limited Gaussian beam
profile is recommended. The defined state and angle of polarization shall be selected. For measurement
systems using conventional radiation sources, an unpolarized beam with a circular profile shall be
realized. The beam profile on the sample surface shall be free of diffraction patterns and parasitic
spots in the outward region. The spatial beam profile on the sample surface shall be recorded and
documented.Optical elements, as for example beam deflection mirrors or beam splitters, may have a reflectivity
which depends on the polarization state of the incident radiation, and they may also deteriorate the
sensitivity of the measurement. The last optical element in front of the integrating sphere shall be
positioned such that the measurement is not influenced by it.For the fractions of the beam reflected and transmitted by the sample, efficient beam dumps shall be
employed to suppress backscattering into the integrating sphere.NOTE 2 An efficient beam dump may be constructed with a stack of optically absorbing neutral density filters.
These filters are arranged for non-normal angles of incidence in a housing with optically absorbing inner walls.
4.2.4 Integrating sphereAn integrating sphere is employed for the collection and integration of the radiation scattered by the
sample. The sphere shall be equipped with beam ports for the entrance and the exit of the probe beam
and the fraction of the beam which is specularly reflected by the specimen. The inner surface shall
be coated with a highly diffusive reflecting material with a Lambertian characteristic and diffuse
reflectivity higher than 97 % for the measurement wavelength. Selected materials suitable for this
coating and the corresponding spectral ranges are listed in Table 2.NOTE 1 Aging of the diffuse reflecting material on the inner walls of the sphere may occur. Corresponding
effects can be detected by monitoring the signal of the sphere with attached diffuse reflectance standard during
long term usage.Table 2 — Selected materials for coating of the inner surface of the integrating sphere
and for diffuse reflectance standardsSpectral range
Material
Barium sulfate 0,35 to 1,4
Magnesium oxide 0,25 to 8,0
Polytetrafluoroethylene 0,20 to 2,5
Gold coating, matt 0,70 to 20
The diameters of the beam ports shall be equal and shall exceed the beam diameter, d , of the probe
beam at the beam ports by at least a factor of five. The port for the detector shall be adapted to the
sensitive area of the detecting element. The detailed shape of the ports shall be optimized for minimum
deterioration of the integrating action and for a contact-free installation of the test sample. Baffles
coated with the same material as the inner surface of the sphere shall be installed between the exit and
entrance port and the detector port. Radiation baffles in front of the detector port are recommended in
order to shield the detector against radiation directly scattered by the specimen to the location of the
detector. For compensation of spatial inhomogeneities of the detector sensitivity, an optional diffuser
may be attached to the detector.© ISO 2021 – All rights reserved 5
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oSIST prEN ISO 13696:2021
ISO/DIS 13696:2021(E)
An interval from 2° to 85° is defined as the minimu
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