ISO 17901-2:2015

INTERNATIONAL ISO
STANDARD 17901-2
First edition
2015-07-01
Optics and photonics — Holography —
Part 2:
Methods for measurement of
hologram recording characteristics
Optique et photonique — Holographie —
Partie 2: Méthodes de mesurage des caractéristiques d’enregistrement
holographique
Reference number
©
ISO 2015
© ISO 2015, Published in Switzerland
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ii © ISO 2015 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 2
5 Principles . 2
6 Measurement methods . 3
6.1 General . 3
6.2 Definition of the Coordinate System. 4
6.3 Hologram recording environment . 4
6.4 Measurement device and apparatus . 4
6.5 Exposure characteristics curve measurement method for recording of the hologram . 6
6.6 Exposure at half-maximum measurement method for recording of the hologram . 6
6.7 Method to measure the R-value of the hologram . 7
6.8 Method to measure the amplitude of refractive index modulation of the hologram . 7
6.8.1 General. 7
6.8.2 Measurement using the transmission hologram . 8
6.8.3 Measurement using the reflection hologram . 8
7 Description of measurement results . 9
7.1 General . 9
7.2 Description of the information concerning the object to be measured . 9
7.3 Description of the measurement results on the exposure characteristics curve and
exposure at half-maximum for hologram recording . 9
7.4 Description of the R-value measurement result of the hologram . 9
7.5 Description of the measurement result of refractive index modulation of the hologram .10
Annex A (informative) Assembly procedure and stability confirmation of hologram
recording optical system based on double-beam interference .13
Annex B (informative) Hologram recording procedure .15
Annex C (informative) Relationship between the hologram and interference fringes due to
double-beam interference .16
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
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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).
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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
iv © ISO 2015 – All rights reserved

Introduction
A hologram is an optical device utilizing interference and applied in numerous fields. In order to
know the exposure characteristics of materials on which the hologram is to be recorded, it is enough
to initially record the hologram under common conditions and subsequently establish the numeral
values representing exposure characteristics by measuring the diffraction efficiency. Though the
hologram-related terms and the measurement method of critical evaluation parameters (diffraction
efficiency, angular selectivity, wavelength selectivity) pertinent to optical characteristics are specified
in ISO 17901-1, there is no stipulation as to the conditions concerning hologram recording or the way to
calculate the numeral values. Therefore, the purpose of this part of ISO 17901 is to provide the terms
and measurement method concerning the hologram exposure characteristics. This part of ISO 17901
does not intend to restrict manufacturing process.
INTERNATIONAL STANDARD ISO 17901-2:2015(E)
Optics and photonics — Holography —
Part 2:
Methods for measurement of hologram recording
characteristics
1 Scope
This part of ISO 17901 specifies the terms and measurement method concerning exposure characteristics
(exposure characteristic curve, exposure at half-maximum, R-value, amplitude of refractive index
modulation) for the hologram recorded by double-beam interference. The materials of hologram to be
measured are not restricted to any particular ones. This part of ISO 17901 does not intend to restrict
manufacturing process.
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
ISO 17901-1:2015, Optics and photonics — Holography — Part 1: Methods of measuring diffraction efficiency
and associated optical characteristics of holograms
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 15902, ISO 17901-1, and the
following apply.
3.1
exposure
product of the laser beam irradiance and exposure time on the recording material surface, when the
hologram is to be recorded on the recording material
Note 1 to entry: Exposure is represented in Joules per square meter (J/m ) in the SI unit system, but may also be
2 2
expressed in micro-Joules per square centimetre (μJ/cm ) or milli-Joules per square centimetre (mJ/cm ).
Note 2 to entry: If the object wave or reference wave enters the detector obliquely in the course of the measurement
of the irradiance, the value of irradiance might not be measured correctly because of reflection on the surface of
the detector. In such an event, it is enough to allow the object wave or reference wave to enter the detector in an
approximately vertical direction to measure the radiant flux and then to divide the obtained value by the flux
sectional area on the recording material surface.
3.2
exposure characteristics curve
curve of measured values plotted with the exposure taken on the axis of abscissa and
the diffraction efficiency taken on the axis of ordinate, which indicate the characteristics of hologram
recording materials
Note 1 to entry: This curve is also called η -E characteristics curve.
3.3
exposure at half-maximum
smallest exposure that can achieve 50 % of the highest diffraction efficiency in the
exposure characteristics curve
Note 1 to entry: This term is a measure to indicate the sensitivity of the hologram recording material. The smaller
the exposure at half-maximum, the smaller the light quantity required for hologram recording.
3.4
R-value
diffraction efficiency of the hologram that has recorded the interference fringes of a certain spatial frequency
Note 1 to entry: For the spatial frequency of interference fringes, the value measured in air is used.
Note 2 to entry: This is an index to indicate the resolution of a recording material in terms of the fine detail
of the interference fringes identified spatially in the hologram. For the finer interference fringes, the recording
material that can achieve the high R-value (diffraction efficiency) can be the recording material that ensures the
high resolution in the hologram. For example, R (1000) is equal to 30 when the diffraction efficiency of hologram
recorded with the spatial frequency of interference fringes being 1 000 lines/mm is assumed to be 30 %.
3.5
spatial frequency
number of interference fringes per unit length
Note 1 to entry: This indicates the density of a periodic pattern of interference fringes and is expressed by the
number of interference fringes repeated per unit length (lines/mm). This is proportional to the reciprocal of the
spacing of interference fringes.
3.6
amplitude of refractive index modulation
amount of modulation of the refractive index and equivalent to the contrast of
interference fringes and the mean refractive index in the recording material of a phase hologram in which
the phase is modulated according to the difference in the refractive indices of the recording material.
Note 1 to entry: This is an index to indicate the phase modulation capacity of recording material and expressed
also in Δn.
4 Symbols and abbreviated terms
NA Numerical aperture of objective
λ Laser wavelength in air (μm)
η Diffraction efficiency (%)
T Thickness of hologram (μm)
θ’ Bragg diffraction angle (angle inside the hologram) (radian)
B
5 Principles
Holograms are recorded through mutual double-beam interference of plane waves. Examples of hologram
recording optical systems are shown in Figure 1. The measurement is made of the diffraction efficiency
of each hologram according to any one of measurement methods specified in ISO 17901-1:2015, 6.5. The
exposure characteristics curve, exposu
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