The new approach to identification of film reflecting holographic marks
The new approach for creation of film reflecting holographic marks for optical security is proposed. Such marks are replicas of a reflecting master hologram recorded on a chalcogenide glass layer. To receive the master hologram, the joint power spectrum of a reference phase mask and an input phas...
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Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України
2011
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| Цитувати: | The new approach to identification of film reflecting holographic marks / S.O. Kostyukevych , L.I. Muravsky, V.M. Fitio, T.I. Voronyak, P.E. Shepeliavyi, K.V. Kostyukevych, N.L. Moskalenko, V.I. Pogoda // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2011. — Т. 14, № 3. — С. 350-356. — Бібліогр.: 13 назв. — англ. |
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irk-123456789-1177612017-05-27T03:04:43Z The new approach to identification of film reflecting holographic marks Kostyukevych, S.O. Muravsky, L.I. Fitio, V.M. Voronyak, T.I. Shepeliavyi, P.E. Kostyukevych, K.V. Moskalenko, N.L. Pogoda, V.I. The new approach for creation of film reflecting holographic marks for optical security is proposed. Such marks are replicas of a reflecting master hologram recorded on a chalcogenide glass layer. To receive the master hologram, the joint power spectrum of a reference phase mask and an input phase mask or a transformed phase mask is produced at the plane of the hologram writing and is modulated by an inclined laser beam. If an inclined laser beam illuminates the replica recorded on a flexible substrate, phase noise including speckle noise is eliminated because the hologram carrier frequency exceeds greatly the limiting frequency of the phase noise power spectrum. Experimental results have shown the principal possibility to produce the high performance film reflecting holographic marks for security applications. The proposed approach can be combined with technologies for fabrication of rainbow holograms. In this case, the received rainbow holograms are the reflecting holographic marks simultaneously. Therefore, they can be verified not only visually, but also by means of automatic identification. 2011 Article The new approach to identification of film reflecting holographic marks / S.O. Kostyukevych , L.I. Muravsky, V.M. Fitio, T.I. Voronyak, P.E. Shepeliavyi, K.V. Kostyukevych, N.L. Moskalenko, V.I. Pogoda // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2011. — Т. 14, № 3. — С. 350-356. — Бібліогр.: 13 назв. — англ. 1560-8034 PACS 06.20.Fb; 02.60.Ed; 02.60.Gf; 07.20.Dt http://dspace.nbuv.gov.ua/handle/123456789/117761 en Semiconductor Physics Quantum Electronics & Optoelectronics Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України |
| institution |
Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| collection |
DSpace DC |
| language |
English |
| description |
The new approach for creation of film reflecting holographic marks for optical
security is proposed. Such marks are replicas of a reflecting master hologram recorded on
a chalcogenide glass layer. To receive the master hologram, the joint power spectrum of
a reference phase mask and an input phase mask or a transformed phase mask is
produced at the plane of the hologram writing and is modulated by an inclined laser
beam. If an inclined laser beam illuminates the replica recorded on a flexible substrate,
phase noise including speckle noise is eliminated because the hologram carrier frequency
exceeds greatly the limiting frequency of the phase noise power spectrum. Experimental
results have shown the principal possibility to produce the high performance film
reflecting holographic marks for security applications. The proposed approach can be
combined with technologies for fabrication of rainbow holograms. In this case, the
received rainbow holograms are the reflecting holographic marks simultaneously.
Therefore, they can be verified not only visually, but also by means of automatic
identification. |
| format |
Article |
| author |
Kostyukevych, S.O. Muravsky, L.I. Fitio, V.M. Voronyak, T.I. Shepeliavyi, P.E. Kostyukevych, K.V. Moskalenko, N.L. Pogoda, V.I. |
| spellingShingle |
Kostyukevych, S.O. Muravsky, L.I. Fitio, V.M. Voronyak, T.I. Shepeliavyi, P.E. Kostyukevych, K.V. Moskalenko, N.L. Pogoda, V.I. The new approach to identification of film reflecting holographic marks Semiconductor Physics Quantum Electronics & Optoelectronics |
| author_facet |
Kostyukevych, S.O. Muravsky, L.I. Fitio, V.M. Voronyak, T.I. Shepeliavyi, P.E. Kostyukevych, K.V. Moskalenko, N.L. Pogoda, V.I. |
| author_sort |
Kostyukevych, S.O. |
| title |
The new approach to identification of film reflecting holographic marks |
| title_short |
The new approach to identification of film reflecting holographic marks |
| title_full |
The new approach to identification of film reflecting holographic marks |
| title_fullStr |
The new approach to identification of film reflecting holographic marks |
| title_full_unstemmed |
The new approach to identification of film reflecting holographic marks |
| title_sort |
new approach to identification of film reflecting holographic marks |
| publisher |
Інститут фізики напівпровідників імені В.Є. Лашкарьова НАН України |
| publishDate |
2011 |
| url |
http://dspace.nbuv.gov.ua/handle/123456789/117761 |
| citation_txt |
The new approach to identification of film reflecting holographic marks / S.O. Kostyukevych , L.I. Muravsky, V.M. Fitio, T.I. Voronyak, P.E. Shepeliavyi, K.V. Kostyukevych, N.L. Moskalenko, V.I. Pogoda // Semiconductor Physics Quantum Electronics & Optoelectronics. — 2011. — Т. 14, № 3. — С. 350-356. — Бібліогр.: 13 назв. — англ. |
| series |
Semiconductor Physics Quantum Electronics & Optoelectronics |
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| fulltext |
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2011. V. 14, N 3. P. 350-356.
PACS 06.20.Fb; 02.60.Ed; 02.60.Gf; 07.20.Dt
The new approach to identification of film reflecting
holographic marks
S.O. Kostyukevycha, L.I. Muravskyb*, V.M. Fitioc, T.I. Voronyakb,
P.E. Shepeliavyia, K.V. Kostyukevycha, N.L. Moskalenkoa, V.I. Pogodaa
aV.Lashkaryov Inst. of Semicond. Physics of the Nat. Acad. Sci. of Ukraine, Kyiv 03028, Ukraine
bKarpenko Physico-Mechanical Inst. of the Nat. Acad. Sci. of Ukraine, Lviv 79601, Ukraine
cNational University “Lvivska Polytechnica”, Lviv 79013, Ukraine
*dep24@ah.ipm.lviv.ua; phone +380 322-633388; fax +380 322-649427
Abstract. The new approach for creation of film reflecting holographic marks for optical
security is proposed. Such marks are replicas of a reflecting master hologram recorded on
a chalcogenide glass layer. To receive the master hologram, the joint power spectrum of
a reference phase mask and an input phase mask or a transformed phase mask is
produced at the plane of the hologram writing and is modulated by an inclined laser
beam. If an inclined laser beam illuminates the replica recorded on a flexible substrate,
phase noise including speckle noise is eliminated because the hologram carrier frequency
exceeds greatly the limiting frequency of the phase noise power spectrum. Experimental
results have shown the principal possibility to produce the high performance film
reflecting holographic marks for security applications. The proposed approach can be
combined with technologies for fabrication of rainbow holograms. In this case, the
received rainbow holograms are the reflecting holographic marks simultaneously.
Therefore, they can be verified not only visually, but also by means of automatic
identification.
Keywords: reflecting holographic mark, chalcogenide glass layer, joint transform
correlator, phase mask, transformed phase mask, optimum exposure, correlation peak,
identification, security verification.
Manuscript received 31.01.11; accepted for publication 14.09.11; published online 21.09.11
1. Introduction
Recently, identification and security verification of
different products, things and documents by optical
methods and means are developed intensively.1-3 The
optical methods and systems possess large possibilities
to resist the counterfeiting due to the parallel encoding-
decoding of large amount of information and, in
particular, 2D and 3D arrays. The techniques utilizing
random phase masks simultaneously with fingerprints,2-7
in particular, the security verification technique2,4 and
the method for optical protection and identification of
documents,6,7 are very perspective among optical
security technologies.
Mentioned above techniques ensure reliable
protection only of such objects, which can contain
random phase masks frequently combined with
fingerprints. Meanwhile, the majority of hardware
products and things are not suitable for protection by
transparent optical marks. One of possible solutions of
this problem is the creation of a reflecting optical mark
by recording a joint power spectrum (JPS) of a
transformed and reference phase masks on a
chalcogenide glass As40S40Se20 at the first stage of a joint
transform correlator (JTC) scheme.8 The resulting
reflecting optical mark is fabricated as a copy of the
written JPS. However, reflecting optical marks can be
copied only on a solid substrate. So, only solid surfaces
of objects to be protected from counterfeiting can be
used for bonding of such marks. If the written JPS is
copied on a film substrate, the optical beam reflecting
from its surface does not reconstruct satisfactorily the
correlation peaks in the first diffraction orders of the
JTC output plane due to influence of power spectrum
density of phase noise (including speckle noise) caused
by any microdeformation of a film layer and its optically
© 2011, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
350
mailto:dep24@ah.ipm.lviv.ua;
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2011. V. 14, N 3. P. 350-356.
© 2011, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
rough surface. The phase noise power spectrum density
is band limited. For example, the highest spatial
frequency of the wideband speckle noise power
spectrum density is equal to resolution limit of an
aberration-free Fourier lens9 used in the JTC first stage.
To separate the phase noise power spectrum from a JPS
of an input and a random phase mask, we propose to
record a reflecting Fourier hologram on a chalcogenide
glass As40S60-xSex layer, where х = 0,10,20. Such
hologram can be considered as a master hologram used
for replication of film reflecting holographic marks
(RHMs). Each RHM is suitable for reconstruction of
correlation peaks, if it is illuminated by an inclined laser
beam.
2. Conditions of master hologram recording
and reconstruction
As shown in our previous paper8, procedures of a
reflecting optical mark fabrication and its identification
can be realized on the basis of a JTC architecture. The
first stage of this correlator was used to produce a
reflecting optical mark written on a solid substrate, for
example, on a chalcogenide glass As40S40Se20 layer. In
linear approximation, this mark can be considered as a
JPS of an input transformed phase mask and a reference
phase mask. The JTC second stage was used for
identification of this mark. Our approach is differed from
previous only by using the inclined reference parallel laser
beam to produce the reflecting master hologram. The
carrier frequency of this beam should exceed greatly the
upper frequency of a phase noise power spectrum. Both a
phase mask and a transformed phase mask can be used as
an input mask to produce a master hologram. The
arrangement for recording of a master hologram is shown
in Fig. 1. To identify the RHM replicated on a flexible
substrate, the parallel laser beam illuminates the RHM
surface. If the slope angle of this beam is identical to the
slope angle of the writing beam, the desired spectral
response containing Fourier spectra of an input and
reference masks is reconstructed along an optical axis
normal to the plane of the RHM placing. If a phase mask
is used as an input mask, the identification criteria are
based only on the intensity of one correlation peak.4,5 If a
transformed phase mask is used as an input mask, the
identification criteria became considerably larger than in
the first case, because the quantity of output correlation
peaks is equal to quantity of separate fragments of the
transformed phase mask. In this case, not only peak
intensities, but also vector distances between peaks can be
regarded as identification criteria.6,7 Let us consider
briefly the linear and nonlinear models of such the RHM’s
producing and identification.
y0
φ
f
r(x,y)
s(x,y)
y0
CGP
FTL
L
CL BS
M
η0
2rA
Fig. 1. Optical arrangement for a master hologram writing on a chalcogenide glass layers As40S60-xSex: L - He-Cd laser ΛΓ-70;
CL - collimating lens; BS - beam splitter; M - mirror; FTL - Fourier transform lens; CGP - chalcogenide glass plate.
2.1. Linear model.
To simplify calculations, we consider only the
deterministic model of a binary phase mask. Let the
rectangular binary phase mask consists of NM ×
identical rectangular pixels and the mask size is
equal
ba×
NbMa× . Then the complex amplitude
transmittance of each pixel can be expressed as
( )[ ]nyymxxj
b
nyy
a
mxx
rectyxnmt
−−
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛ −−
=
,exp
,),(,
θ
, (1)
where ( )1
2
+−= Mccmxm , ( 1
2
++−= Nddnyn ) are
the coordinates of the pixel center; ; Mm ,...,2,1=
Nn ,...,2,1= ; θ is the pixel phase equal to lπ2 or
ππ +l2 , ,...2,1,0=l .
351
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2011. V. 14, N 3. P. 350-356.
Let a reference phase mask r and an input phase
mask s are entered into an input plane (x,y) of a
conventional JTC (see Fig. 1). If these masks are
identical, they can be expressed as7,8
),( yxr
,,
,
0
1 1
0
⎥
⎦
⎤
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛ +−−
−
−⎢
⎣
⎡
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛ +−−
=
−−
= =
++∑∑
b
yyy
a
xx
rect
b
yyy
a
xx
rect
nm
M
m
N
n
nm
(2)
© 2011, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
=),( yxs
,,
,
0
1 1
0
⎥
⎦
⎤
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛ −−−
−
−⎢
⎣
⎡
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛ −−−
−−
= =
++∑∑
b
yyy
a
xx
rect
b
yyy
a
xx
rect
nm
M
m
N
n
nm
(3)
where xm+, yn+ are the coordinates of the pixel with the
complex transmittance ; x1, +=nmt m-, yn- are the
coordinates of the pixel with the complex transmittance
; 2y1, −=nmt 0 is the distance between two masks. Let us
the inclined parallel laser beam illuminating the
chalcogenide glass plate disposed in the JTC frequency
domain is expressed by next equation:
( ) ( )vyjAvH hπ2exp0 −= , (4)
where v is the spatial frequency along the axis η
r
in the
Fourier plane, ϕtgfyh ⋅= , ϕ is the angle of the parallel
laser beam inclination to the optical axis of the JTC first
stage, f is the focal length of a Fourier transform lens
(see Fig. 1). If a reflecting photosensitive material
disposed in the JTC Fourier plane is linear and the
complex amplitude transmittances of input and reference
phase masks are identical, i.e. =( )0, yyxr − ( )0, yyxs + ,
the intensity distribution of the reconstructed
interference pattern recorded on this material is
proportional to
( ) ( ) ( ) ( ) =−++= 2
0
2 2exp,,, vyjAvuSvuRvuT hπ
+++++ SRRSASSRR **** 2
0
+ ( ) ( )[ ]++ ∗∗ vyjSAvyjRA hh ππ 2exp2exp 00
( ) ( )[ ]vyjASvyjAR hh ππ 2exp*2exp* 00 −+− , (5)
where * is the complex conjugation symbol,
( ) ( )[ ]
( ) ( ) ( ) ( ) ( ) ,,j2expsinsin
,,
,0 vuWvybvcaucab
yxrFvuR
nmπ=
==
( ) ( )[ ] ( ) ( ) ( )
( ) ( ) , ,j2-exp
sinsin,,
,0 vuWvy
bvcaucabyxsFvuS
nmπ×
×==
( ) =vuW nm ,,
( ) ([
( ) ( )] ,2exp2exp
2exp2exp
1 1
vyjuxj
vyjuxj
nm
M
m
N
n
nm
−−
= =
++
−−−
−−−∑∑
ππ
ππ )
,
F is the symbol of 2D Fourier transform.
If the same parallel laser beam expressed by Eq. (4)
illuminates a master hologram recorded on a
photosensitive material, the signal reconstructed along the
optical axis of the JTC second stage can be expressed as
( ) ( )vyjAvuU hπ2exp, 0 −=
( ) ( )[ ]vyjSAvyjRA hh ππ 2exp2exp 00
∗∗ + = ( )SRA +2
0 . (6)
This signal is produced by reconstruction of the
sixth term ( ) ( )[ ]vyjSAvyjRA hh ππ 2exp2exp 00
∗∗ + of the
intensity distribution ( ) 2,vuT expressed by Eq. (5).
Signal ( )vuU , is projected on an optically addressed
SLM or a digital camera by using the telecentric imaging
system containing two lenses. In this imaging system,
the front focal plane of the first lens should coincide
with the disposition plane of a sensitive material surface
and the back focal plane of the second lens should
coincide with the plane of a SLM or a sensor array
disposition. The output correlation field can be obtained
by Fourier transform of the recorded by a linear optically
addressed SLM or a digital camera intensity distribution
proportional to ( )2,vuU , which is expressed as
( )2,vuU ( )SRRSSSRRA ****4
0 +++= . (7)
The desired output correlation field is produced
after optical Fourier transform of intensity distribution
( )2, MvuU recorded on a SLM or after digital Fourier
transform of intensity distribution ( )2, DvuU recorded by
a digital camera. If the image sampling is not taken in
account, the linear approximation of complex amplitude
spatial distribution of both ( )2, MvuU and ( )2, DvuU
Fourier transforms can be written as
( ) ( ) ( ) ( ) =′′+′′+′′=′′ −+ yxCyxCyxCyxC ,,,, 0
= ( )( )abMN ⎢
⎣
⎡
⎟
⎠
⎞
⎜
⎝
⎛ ′′
Λ
b
y
a
x ,2 + ⎟
⎠
⎞
⎜
⎝
⎛ ′−′′
Λ
b
yy
a
x 02, +
⎥
⎦
⎤
⎟
⎠
⎞
⎜
⎝
⎛ ′+′−′−
Λ
b
yy
a
x 02, + ),(~2 0 yxn ′′ + ),(~ yxn ′′ +
),(~ yxn ′−′− , (8)
where ( )yxC ′′,0 is the signal located in the dc;
( )yxC ′′+ , , ( )yxC ′′− , are the correlation signals located
in the +first and –first diffraction orders respectively;
2 ( )( )abMN ⎟
⎠
⎞
⎜
⎝
⎛ ′′
Λ
b
y
a
x , is the autocorrelation peak
amplitude distribution in the dc;
( )( )abMN ⎟
⎠
⎞
⎜
⎝
⎛ ′′±′±
Λ
b
yy
a
x 02, m is the correlation peak
amplitude distribution in the ±first order; ),(~
0 yxn ′′ ,
),(~ yxn ′′ and ),(~ yxn ′−′− are the cross-talk noise
352
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2011. V. 14, N 3. P. 350-356.
η,υ
MH or RHM
FTL
DFT
DC2
ID
ID
M
SLM BS
DC1 TIS
η′,υ′
CL
L
TC
TC
ϕ
Fig. 2. Arrangement of a master hologram or a replicated RHM reconstruction: MH - master hologram; TIS - telecentric imaging
system; M - mirror; SLM - optically addressed spatial light modulator; L - laser; CL - collimating lens; BS - beamsplitter; FTL-
Fourier transform lens; DC1, DC2 - digital cameras; DFT - digital Fourier transform; TC - threshold comparison; ID -
identification device; η,v, axes of planes (ξ,η) and (u,v); η′,v′, axes of planes (ξ′,η′) and (u′,v′).
amplitude distributions in the dc, +first and –first orders
respectively. The arrangement of reconstruction of a
master hologram or a replicated RHM is shown in Fig. 2.
2.2. Nonlinear model.
We have proposed one of possible approaches for
evaluation of output response in a nonlinear JTC with
photosensitive materials in the frequency domain, if the
reference and input phase masks are entered into the JTC
input plane.8,10 This approach is based on fulfillment of
two basic conditions: i) definition of the diffraction
efficiency η versus exposure experimental
dependence (exposure characteristic) for a
photosensitive medium or a SLM; ii) mathematical
representation of the interference pattern, which should
be written on a photosensitive medium or a SLM. If the
exposure characteristic and the function describing or
approximating the written interference pattern are
known, one can find the optimum writing exposure E
E
opt,
the reading round aperture’s Ar normalized radius
( )[ ] ( )[ ]22
AAA vvbuua −+−=ρ and the normalized
distance ( ) ( )22
AAA bvauw += from the frequency
plane (u,v) origin to the aperture center, where uA, vA are
the coordinates of the aperture center. First condition for
realization of the proposed approach can be satisfied
experimentally. For this purpose, we can measure the
exposure characteristic η=η(E) of a chalcogenide glass
layer As40S50Se10 by using the conventional optical
scheme for writing of reflecting holographic gratings. To
satisfy second condition, it is necessary to provide the
computer simulation of Eq. (5). But both the computer
simulations of Eq. (5) and further procedures of its
transformation demand the program design and the large
amount of computations. Therefore, we have decided to
determine Eopt, ρA and wA during experimental recording
of RHMs and their reconstruction.
3. Experimental results
The application of a chalcogenide glass as an inorganic
photoresist with high resolution (~5⋅103 mm-1) is based
on the effect of photostimulated change of chalcogenide
glass film solubility in its selective solvent.11 Such films
are produced by thermal vacuum film deposition. The
mentioned above effect is exhibited in increase or
decrease of the dissolution rate of irradiated sections in
comparison with the dissolution rate of a non-irradiated
layer depends upon the solvent type. In these cases, the
positive or negative selective etching of a chalcogenide
glass layer is occurred. Such photoresists are
successfully used for making of holographic diffraction
elements, synthesized holograms, konoforms, master
mirror disks (CD, DVD) etc.12
In order to produce the master holograms, we have
used chalcogenide glass layers As40S60-xSex, where х = 0;
10. To fabricate the plates containing such layers, firstly a
chromium (Сr) layer with thickness equal to 30 nm was
coated on a glass substrate, secondly a chalcogenide glass
layer As40S60-xSex with thickness equal to ~500 nm was
coated on a Cr layer. The coating was realized by step-by-
step thermal spraying in vacuum with the residual
pressure <10–3. The etching of an exposed chalcogenide
glass layer was realized in an anhydrous organic selective
etchant of negative type.13 The plate can contain only a
chalcogenide glass layer. But if the Cr layer is evaporated
previously on a glass substrate, the diffraction efficiency
of such hologram can be increased greatly. Besides, the
hologram wear resistance is increased significantly.
© 2011, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
353
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2011. V. 14, N 3. P. 350-356.
3.1. Measurement of diffraction efficiency of a
chalcogenide glass layer
For approximate estimation of optimum exposure Eopt,
we have measured the exposure characteristic η=η(E) of
a chalcogenide glass layer As40S50Se10. This
characteristic was measured by using the conventional
optical arrangement for writing of reflecting holographic
gratings. A He-Cd laser (λw = 442 nm) was used for their
writing with different exposures. The reference beam
angle was equal to 30 deg concerning the optical axis of
this arrangement. The diffraction efficiency of each
written grating was measured by using the usual
arrangement of a reflecting grating reading by a laser
diode module MLRZ-650-005 (λr = 650 nm). The
received dependence η=η(E) is depicted in Fig. 3.
Calculations of the optimum exposure represented in our
previous paper8 have shown that one is disposed on the
dip of curve η=η(E) after reaching its peak value, if 0.1
≤ ρ A ≤ 0.4 and wA ≤ 0.66. So, we chose the exposures in
the range from 100 mJ/cm2 up to 200 mJ/cm2 and the
normalized radius ρ A = 0.1 disposed on the normalized
distance wA = 0.5 from the frequency plane (u,v) origin.
3.2. Writing of reflecting master holograms and
replication of RHMs
The binary reference and transformed masks were used
for master hologram writing on a chalcogenide glass
layers As40S60-xSex. Each the mask contains 256×256
adjacent square pixels with complex transmittances
equal to +1 or –1 for wavelength λ = 442 nm. In these
masks, the dimensions of pixels are equal to 20×20 μm
and the pixel pitch is equal to 20 μm. The transformed
phase masks consisting of two, three and nine fragments
of a reference phase mask were used together with a
reference phase mask to produce a JPS. The
configuration of the two-fragment transformed mask
made from the reference phase mask is shown in Fig. 4.
10
20
30
40
η ,%
Е , mJ/cm2
70 140 210 280 310E0
Fig. 3. Dependence η = η(E) for a chalcogenide glass
As40S50Se10.
1
23
4
2
4
4 1
3
off
a) b)
1
4 3
4
c)
Fig. 4. Procedure of the first stage of the two-fragment
transformed phase mask fabrication: reference phase mask (a);
separation of reference mask on two fragments: replication of
quadrant 4 and replacement of quadrant 2 by quadrant 4 (b);
transformed phase mask (c).
The optical arrangement for the master hologram
writing on a chalcogenide glass layers As40S60-xSex is
represented in Fig. 1. This arrangement containing a
Fourier lens with focal length f = 700 mm is based on a
JTC first stage. The binary reference and transformed
masks were entered and the distance between two masks
was equal to 8.0 mm. The collimated parallel He-Cd
laser (ΛΓ-70, λw = 442 nm) beam was used for
illumination of phase masks and shaping of a reference
parallel laser beam illuminated the chalcogenide glass
layer at angle ϕ =30 deg concerning the optical axis of
the arrangement. To adjust the intensities of a JPS and a
reference beam and estimate the desired range of
exposures, first we entered the calibrated photodiode
ΦD-7K in the frequency plane (u,v) and disposed its
center on the distance == fw
b wvA λπη ,0 24.3 mm from
the frequency plane origin. The distance η0 corresponds
to normalized distance 0.5 along the axis v== bvw vA,
r
,
which evaluates the position of a center of a round
aperture Ar with normalized radius ρA = 0.1. Because the
radius of this aperture is equal to == f
b
r wAA λρπ 4.86
mm, we have mounted the round aperture with diameter
= 9.7 mm directly in front of the photodiode along
the direction opposite to the direction of the reference
beam propagation (see Fig. 1). The measured mean
intensity
Ar2
( )vuIm , of the JPS part selected by the round
aperture was equal to 0.8 mW/cm2. To ensure maximum
© 2011, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
354
Semiconductor Physics, Quantum Electronics & Optoelectronics, 2011. V. 14, N 3. P. 350-356.
modulation of a selected JPS area, we have chosen the
same intensity of the reference beam measured by this
photodiode at the same place. So, the exposure time
range for writing of reflecting master holograms on a
chalcogenide glass layer was calculated by using the
justified above exposure range and measured mean
intensities of the JPS and the reference light beam. This
time was defined over the range from 62s up to 125s.
Because the area for writing of a master hologram is
restricted by a round aperture, we have recorded several
master holograms on the same chalcogenide glass layer.
To fabricate RHMs, we have used the
photopolymer “Yantar’-3” developed in the Institute of
Macromolecular chemistry of the NAS of Ukraine. All
master holograms written on chalcogenide glass layers
As40S50Se10 and As40S60 were replicated on this
photopolymer. The photopolymer was deposited on a
lavsan carrier. After replication of a master hologram on
a photopolymer, the photopolymer surface was coated
by a thin Al layer.
3.3. Reconstruction and analysis of RHMs and
refelecting master holograms
The experimental setup arrangement for reconstruction of
RHMs and reflecting master holograms is shown in Fig.
5. The optical part of this setup contains a laser diode
module MLRZ-650-005 to produce an expanded parallel
laser beam (λr = 650 nm) illuminating a RHM or a master
hologram at the same angle of 30 deg. The reconstructed
response evaluated by Eq. (6) in linear
approximation is projected by a telecentric imaging
system containing two lenses with focal lengths f
( )vuU ,
1 and f2
on a CCD camera “FINE” T-392C. The telecentric
imaging system is placed along the optical axis normal to
the plane of a reflecting hologram disposition. The
horizontal camera resolution is equal to 81.6 lp/mm and
the vertical camera resolution is equal to 58 lp/mm, the
sensor array’s active (image) area is equal to 4.9 mm by
3.7 mm. To ensure the reliable reconstruction of a JPS
recorded by the CCD camera and evaluated by Eq. (7), we
selected the lenses in the telecentric imaging system,
which focal lengths f1 and f2 are related as 2:1. In this case,
the JPS carrier spatial frequency that is equal to 26 mm-1
is translated to 52 mm-1 and the carrier spatial frequency
of a recorded JPS does not exceed the vertical camera
resolution. Such demagnification of the telecentric system
allows recording all area of an interference pattern
projected on the sensor array from a chalcogenide glass
layer in horizontal direction and only three fourth of this
area in vertical direction. The JPS recorded by the CCD
camera is captured by a frame grabber and entered into a
PC. Due to the Digital Fourier transform of the digitized
JPS, the output correlation response containing several
correlation peaks in the ±first diffraction order is
produced. The part of correlation response covering the
first diffraction order area is used for creation of an
identification feature vector and its comparison with a
reference feature vector.6,7
CCD
ϕ
2rA FG
DFT
I
f1 f2
TIS
MH or RHM PC
Fig. 5. Experimental setup arrangement for reconstruction of
RHMs and refelecting master holograms: MH, master
hologram; RHM, reflecting holographic mark; TIS, telecentric
imaging system; M, mirror; CCD, CCD camera; PC, personal
computer; FG, frame grabber; DFT, digital Fourier transform;
I, identification.
The results of reconstruction of master holograms
and RHMs are represented in Fig. 6 and Fig. 7
respectively. In this case, the two-fragment transformed
phase mask represented in Fig. 4, was used together with
the reference phase mask for writing the master
hologram. These Figures show that two peaks in ±first
diffraction order are very sharp and narrow. In Fig. 6,
the peak at the center of the ±first diffraction order is
produced as a result of autocorrelation of the
transformed mask larger fragment with the
corresponding fragment of the reference mask, and the
second peak is the product of autocorrelation of the
transformed mask smaller fragment with fourth quadrant
of the reference mask. In Fig. 7, the correlation peaks are
dissymmetrical to the correlation peaks reperesented in
Fig. 6. Such behavior of the correlation peaks is clear,
because all studied RHMs are mirror reflections of
corresponding master holograms. The produced peaks
can be identified easily by automatic means.
Fig. 6. Correlation peaks in +first and –first diffraction orders
as a result of reconstruction of the master hologram. Two-
fragment transformed phase mask (see Fig. 4) was used to
record the master hologram.
© 2011, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
Fig. 7. Correlation peaks in +first and –first diffraction orders
as a result of reconstruction of the RHM. Two-fragment
transformed phase mask (see Fig. 4) was used to record the
master hologram.
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Semiconductor Physics, Quantum Electronics & Optoelectronics, 2011. V. 14, N 3. P. 350-356.
5. Conclusions
The proposed approach for fabrication and identification
of RHMs on a flexible substrate has some advantages in
comparison with the previous similar approach for
fabrication and identification of ROMs on a solid
substrate.8 The main advantage consists in removal of
the phase and speckle noise caused by any
microdeformation of a film layer and its optically rough
surface. This noise does not allow reconstructing the
correlation response from ROM’s replicas written on a
flexible substrate. The fulfilled experiments with
identification of RHMs have shown the high
performance of photopolymer RHMs on a lavsan carrier.
Such RHMs can be used successfully for identification
and security verification of different products and things.
Because the proposed approach can be combined
with technologies for fabrication of rainbow holograms,
the unique possibility of quantitative identification and
security verification of rainbow holograms fabricated by
using our approach became realizable. Indeed, such
rainbow holograms can be treated simultaneously as
RHMs. Therefore they can be verified not only visually,
but also by means of automatic identification. The
created setup for reconstruction of RHMs can be used as
a prototype of an automatic system for identification and
security verification of rainbow holograms..
References
1. R.L. van Renesse., Ed., Optical Document Security,
Second ed., Artech House, Norwood / London
(1998).
2. B. Javidi, “Securing information with optical
technologies,” Phys. Today 50, 27-32, 1997.
3. “Special Section on Optical Security,” J.L. Horner,
B. Javidi, Eds., Opt. Eng. 38, 8-119, 1999.
4. B. Javidi, J.L. Horner, “Optical pattern recognition
for validation and security verification,” Opt. Eng.
33, 1752-1756, 1994.
5. E.G. Johnson, J.D.Brasher, D.A Gregory, P.
Erbach, M. Duignan, G. Behrman, S.H. Lee, W.
Daschner, P. Long, “Optical recognition of phase-
encrypted biometrics,” Opt. Eng. 37, 18-26, 1998.
6. L.I. Muravsky, T.I. Voronyak, V.M. Fitio, M.V.
Shovgenyuk, “Transformed phase mask and
photoanisotropic material in optical correlators
applied for security verification,” Opt. Eng. 38, 25-
32, 1999.
7. L.I. Muravsky, “Optical correlation systems for
fingerprint and phase mask identification,” A.A.
Akaev, S.B. Gurevich, K.M. Jumaliev, L.I.
Muravsky, T.A. Smirnova, Holography and optical
information processing: selected sections, 227-444,
Uchkun, Bishkek, St. Petersburg, 2003 (in
Russian).
8. L.I. Muravsky, S.O. Kostyukevych, T.I. Voronyak,
P.E. Shepeliavyi, “Study of chalcogenide glass
based reflecting optical marks,” SPIE-IS&T
Electronic Imaging Proc. 5310, 377-386, 2004.
9. I. Yamaguchi, “Fundamentals and applications of
speckle,” SPIE Proc. 4933, 1-8, 2003.
10. L.I. Muravsky, “Identification of random phase
masks in a nonlinear joint transform correlator,”
SPIE Proc. 4148, 185-193, 2000.
11. B.T. Kolomietc, V.M. Lyubin, V.P. Shilo,
“Photostimulated changes of chalcogenide glass
solubility,” Phys. And Chem. of Glass, 4, 351-357,
1978 (in Russian).
12. I.Z. Indutnyi , A.V. Stronski, S.A. Kostyukevych,
P.F. Romanenko , P.E. Shepeliavyi, I.I. Robur,
“Holographic optical elements fabrication using
chalcogenide layers,” Opt. Eng. 34, 1030-1039,
1995.
13. Patent of the Russian Federation #2008285. I.Z.
Indutnyi, S.A. Kostyukevych, P.E. Shepeliavyi,
“Solution for negative etching of chalcogenide
glasses,” Otkrytiya, izobretieniya, #4, 1994 (in
Russian).
© 2011, V. Lashkaryov Institute of Semiconductor Physics, National Academy of Sciences of Ukraine
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