ISO 17901-1:2015

INTERNATIONAL ISO
STANDARD 17901-1
First edition
2015-07-01
Optics and photonics — Holography —
Part 1:
Methods of measuring diffraction
efficiency and associated optical
characteristics of holograms
Optique et photonique — Holographie —
Partie 1: Méthodes de mesurage de l’efficacité de diffraction et
caractéristiques optiques associées aux hologrammes
Reference number
ISO 17901-1:2015(E)
©
ISO 2015

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ISO 17901-1:2015(E)

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ISO 17901-1:2015(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 3
5 Principles . 3
6 Measurement methods . 3
6.1 General . 3
6.2 Definition of the coordinate system . 4
6.3 Hologram measurement environment . 4
6.4 Measurement device and measures . 5
6.5 Diffraction efficiency measurement method . 5
6.5.1 General. 5
6.5.2 Absolute diffraction efficiency measurement method . 6
6.5.3 Relative diffraction efficiency measurement method . 7
6.5.4 Spectral diffraction efficiency by transmittance measurement for
volume holograms . 8
6.5.5 Spectral diffraction efficiency by reflectance measurement for
volume holograms . 9
6.6 Angular selectivity measurement method .11
6.7 Wavelength selectivity measurement method .11
7 Description of measurement results .12
7.1 General .12
7.2 Description of the diffraction efficiency measurement results .12
7.3 Description of the angular selectivity measurement results .12
7.4 Description of the wavelength selectivity measurement method .12
Bibliography .14
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ISO 17901-1:2015(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 WTO principles in the Technical Barriers
to Trade (TBT) see the following URL: Foreword - Supplementary information.
The committee responsible for this document is ISO/TC 172, Optics and Photonics, Subcommittee SC 9,
Electro-optical systems.
ISO 17901 consists of the following parts, under the general title Optics and photonics — Holography:
— Part 1: Methods of measuring diffraction efficiency and associated optical characteristics of holograms
— Part 2: Methods for measurement of hologram recording characteristics
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ISO 17901-1:2015(E)

Introduction
The aim of this part of ISO 17901 is to specify the terms related to holograms and basic measurement
methods to characterize them.
A hologram is an optical device utilizing interference and diffraction phenomena and is characterized
differently from optical devices based on reflection, refraction, and scattering. By exploiting the
characteristics of holograms, they have been successfully applied in numerous applications such as
displays, metrology, and anti-counterfeit security.
The expanded market in holography has generated a need to agree on basic terms and definitions for
holograms and measurement methods and this part of ISO 17901 aims to satisfy that need.
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INTERNATIONAL STANDARD ISO 17901-1:2015(E)
Optics and photonics — Holography —
Part 1:
Methods of measuring diffraction efficiency and associated
optical characteristics of holograms
1 Scope
This part of ISO 17901 specifies the terms related to optical characteristics of holograms, the method
to measure their diffraction efficiency, and the angular and wavelength selectivity measurement
methods. These measurement methods are applicable to any type of hologram if the hologram yields
a simple diffraction pattern, which means the reconstructed wave can be clearly separated from other
diffracted and non-diffracted waves. In other words, holograms that yield complex diffraction patterns
are excluded. There are no restrictions on the materials used to form the holograms.
2 Normative references
The 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 15902, Optics and photonics — Diffractive optics — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 15902 and the following apply.
3.1
hologram
interference pattern formed between the wave emitted from the object and its coherent reference wave,
which is recorded in the recording material
Note 1 to entry: The holograms also include those formed through embossed copying of surface relief or those
recording the periodic structure spatially by etching or engraving.
3.2
object wave
object beam
wave emitted from an object and entering the recording material in the course of recording the hologram
3.3
reference wave
reference beam
wave entering the recording material while forming a certain angle with the object wave in the course
of recording the hologram
3.4
illuminating wave
illuminating beam
wave allowed to enter the hologram when reconstructing the image from the hologram
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ISO 17901-1:2015(E)

3.5
reconstructed wave
reconstructed beam
wave diffracted by the hologram
Note 1 to entry: Generally, this term indicates either the +first-order diffracted wave or –first-order diffracted
wave but can indicate second or higher order diffracted waves.
3.6
specular wave
perfectly reflected light waves, to be distinguished from diffuse reflection
3.7
transmission hologram
hologram using transmission reconstructed waves
Note 1 to entry: A hologram recording the interference pattern between objects and reference waves from the
same side of the recording material is a transmission hologram.
3.8
reflection hologram
hologram using reflection reconstructed waves
Note 1 to entry: A reflection hologram recording the interference pattern between an object wave and the reference
wave from the mutually opposite sides of the recording material is generally a volume reflection hologram and is
also called a Lippmann or Lippmann Denisyuk hologram. Of the surface relief hologram (3.13), the hologram using
the wave reflected from the relief surface is a surface relief reflection hologram.
3.9
phase hologram
hologram having a spatially-periodic phase modulation structure
3.10
amplitude hologram
hologram having a spatially-periodic amplitude modulation structure
3.11
volume hologram
hologram causing Bragg diffraction
Note 1 to entry: A hologram having a sinusoidal refractive–index distribution is one whose hologram recording
layer is sufficiently thicker than the interval of interference fringes. Holograms characterized by a Q-value Q1
are considered to be volume holograms.
3.12
plane hologram
hologram causing Raman-Nath diffraction
Note 1 to entry: This type of hologram is the one whose hologram recording thickness is sufficiently smaller than the
interval of interference fringes. Holograms characterized by a Q-value Q < 1 are considered to be plane holograms.
3.13
surface relief hologram
hologram recording the interference pattern as relief structure in the surface of the hologram
recording material
3.14
Q-value
in the periodic structure based on the sinusoidal refractive-index distribution, the value of Q defines the
thickness of the diffraction grating and is determined by the following formula:
2πλT
Q=
2
nd
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ISO 17901-1:2015(E)

where
T is the thickness of hologram (μm);
λ is the wavelength in air (μm);
d is the interval of interference fringe (μm);
is the mean refractive-index of hologram
n
Note 1 to entry: This value is used to classify the hologram into the volume hologram and the plain hologram.
Note that this value is applicable only to the cyclic structure based on the sinusoidal refractive-index distribution.
3.15
diffraction efficiency
ratio of the radiant flux of the reconstructed wave relative to the radiant flux of the
illuminating wave
Note 1 to entry: The diffraction efficiency of holograms is generally expressed as a percentage (%).
3.16
angular selectivity
dependence of the radiant flux of the reconstructed wave on the angle of incidence
of the illuminating wave if the hologram is reproduced while using a monochromatic illuminating wave
3.17
wavelength selectivity
dependence of the radiant flux of the reconstructed wave on the wavelength of the
illuminating wave if the hologram is reproduced while keeping the angle of incidence of illuminating
wave constant
4 Symbols and abbreviated terms
η Diffraction efficiency (%)
5 Principles
The diffraction efficiency is determined by measuring the radiant flux of the reconstructed wave or the
zero-order diffracted wave while the illuminating wave enters the hologram. The absolute diffraction
efficiency, which is the ratio of the radiant flux of reconstructed wave relative to that of the illuminating
wave, is the basis of the measurement. The relative diffraction efficiency, which is the ratio of the
radiant flux of the reconstructed wave relative to that of the sum of the radiant fluxes of all diffraction
orders, might be important for certain applications. There is also a simplified method to determine the
diffraction efficiency from the spectral distribution of either the transmittance or reflectance of the
hologram. Finally, the angle selectivity of the hologram is determined from diffraction efficiency as
a function of the angle of incidence and the wavelength selectivity is determined from the diffraction
efficiency as a function of the wavelength.
6 Measurement methods
6.1 General
This part of ISO 17901 covers the measurement of the diffraction efficiency as well as the angle
selectivity and wavelength selectivity as described below. Since for multiple purposes there is more
than one definition of diffraction efficiency, its measurement shall be made according to the method
appropriate to the purpose.
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ISO 17901-1:2015(E)

When the hologram to be measured is formed through the two-flux interference of reference waves,
they are assumed to be plane waves. If the reference waves are not plane waves, the method can be
applied by using either the absolute diffraction efficiency or relative diffraction efficiency. If this applies,
the fact shall be cited clearly in the report.
This part of ISO 17901 is applicable to holograms formed by the method other than two-flux interference
of laser beams, such as the embossed hologram formed by transferring and reproducing the interference
pattern, the hologram formed by the electron beam lithography system, and all other etching or
engraving methods. If any alternative method is used, that fact shall be cited clearly in the report.
6.2 Definition of the coordinate system
The axis of coordinates and the angle of waves are defined as follows.
a) The recording material (or hologram) plane shall be the xy-plane while the axis vertical to the plane
shall be the z-axis.
b) For the z-axis, the advance direction of the object or reconstructed wave shall be positive.
c) As shown in Figure 1, the angle of incidence θ [degree (°) or rad] is formed between the z-axis in
the positive direction and the extension of the incident wave. The positive θ−symbol indicates a
counter-clockwise direction.
a) Wave advancing in the +z direction b) Wave advancing in the –z direction
Key
1 incident light wave
2 recording material or hologram
Figure 1 — How to establish the coordinate system and wave angle in measurement of optical
characteristics of holograms
6.3 Hologram measurement environment
Measurement of the diffraction efficiency shall be made inside a dark room at room temperature and in
atmosphere with stable relative humidity (or under conditions designed to prevent entry of stray light
into the detector).
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ISO 17901-1:2015(E)

6.4 Measurement device and measures
The measurement shall use the following equipment and measures, as required, according to the
measurement method.
a) Light source
The light source for laser should ensure high temporal stability of the output (for example, ±5 % or
less in output fluctuation over 30 min). The white-light illuminating source, if used, should provide
a continuous spectrum over the measuring wavelength range concerned.
b) Mirror
The surface accuracy of mirrors should be sufficiently high (for example, better than 1/10 of the
appropriate wavelength).
c) Holder
The holder should be able to move within a movable range equivalent approximately to the test
piece size while holding the hologram.
d) Detector
The detector should have sufficient dynamic range and response relative to the intensity to be
measured and should have been calibrated.
e) Monochromator
The monochromator should have a spectral resolution of 1 nm or less within the wavelength range
to be measured.
f) Integrating sphere
Spherical optical component with the inner wall covered by a light diffusing material of high
reflectance which can collect beams and homogenize them through spatial integration.
NOTE A typical coating material used for integrating spheres is barium sulfate.
6.5 Diffraction efficiency measurement method
6.5.1 General
In the strict sense of the word, diffraction efficiency is the absolute diffraction efficiency as measured
according to the method described in 6.5.2.
However, the absolute diffraction efficiency might not be appropriate to represent the characteristics of
certain recording materials that cause loss of light due to the hologram’s reflection, scattering, absorption,
and contraction properties. In such a case, it is recommended to apply the method described in 6.5.3.
In th
...