We discuss a method for the recording of multiple images in a photorefractive LiNbO3 crystal which needs only a
single object beam without any reference beam. The object beam is modulated by a lenticular lens array sheet to produce
a set of sub-object beams. These beams are angularly separated on the recording plane but are made to overlap by light
scattered light by the photorefractive LiNbO3 crystal. The result is that only a single beam is needed to record multiple
holograms. Experimental results show that four holograms can be stored in a photorefractive LiNbO3:Fe crystal 30 mm
X 30 mm X 1 mm in size at the same time. The proposed method makes it especially simple to produce one-beam
write/read multiple holograms.
This work presents a novel method for optical decrypted key production by screen printing technology. The key is
mainly used to decrypt encoded information hidden inside documents containing Moire patterns and integral
photographic 3D auto-stereoscopic images as a second-line security file. The proposed method can also be applied as an
anti-counterfeiting measure in artistic screening. Decryption is performed by matching the correct angle between the
decoding key and the document with a text or a simple geometric pattern. This study presents the theoretical analysis and
experimental results of the decoded key production by the best parameter combination of Moire pattern size and screen
printing elements. Experimental results reveal that the proposed method can be applied in anti-counterfeit document
design for the fast and low-cost production of decryption key.
In this work we present a single exposure method for recording multiple holograms in reflection holography. In this
novel method, the input pattern is a segmented image composed of alternating slices of several original images and
modulated by a lenticular lens array sheet. A set of object beams can be produced simultaneously, which are angularly
separated on the recording plane and overlap one reference beam at the same time. Therefore, only one exposure is
needed for holographic recording multiple holograms. Experimental results show that a lenticular lens array sheet placed
as a modulator in the path of the object beam provides a simple yet effective ingredient of creating multiple images for
single-exposure holography. The proposed method is especially useful for one-step write/read multiple holograms and
for stereoscopic display applications.
We propose a novel optical holographic encrypted data storage scheme based on phase encoding multiplexed scheme. In the proposed data storage scheme, patterns of encrypted images are stored holographically in a photorefractive LiNbO3:Fe crystal by using lenticular lens array (LLA) sheet phase-encoded multiplexing.
Experimental results show that rotating a LLA placed as a phase modulator in the path of the reference beam provides a simple yet effective method of increasing the holographic storage capabilities of the crystal. Combining this rotational multiplexing with two-axis tilting multiplexing offers not only further data storage
capabilities but also data encryption possibilities.