Serialized holography for brand protection and authentication.

A zoom objective lens for a multi-layer optical rec ording has been designed. A newly proposed optical power arrangement enables varying back focal length while focal length invariant by a linear movement of sin gle zooming component. The zoom lens is implemented into multi- layer and multi-bit holographic recording system em ploying 405 nm blue lasers. 1. INTRODUCTION Recently, multilayer micro holographic optical disc systems have been investigated to attain high capa city and high data transfer rate [1,2]. In the multilayer recordi ng, micro-holograms are recorded throughout the vol ume of recording material by changing the recording depth. For such multilayer recording systems, objective l ens accesses to multiple recording layers. The design of objecti ve lens needs to satisfy couple of constraints. Fir st, working distance, air spacing between objective lens and re cording disc, is unchanged while changing the recor ding layer. Numerical aperture (NA) must be an invariant for th e range of recording depth to equalize transverse s ize and modulation of index of refraction of the micro holo grams. Ideally, the number of moving elements shoul d be a minimum. Also, a linear relation between zooming of the element and recording depth is preferable. Typical way to design such optics is depicted in Fi g. 1. First, an intermediate image, a virtual or re al one, is formed by a movable zooming optics. Then, the inter mediate image is relayed to a final focal point ins ide a recording medium by a secondary optics consisting o f high NA objective elements. Moving the first opti cs along optical axis alters conjugate ratio between the int ermediate image and final image, therefore, the fin al image position also moves, which ends up with selection of writing depth. The approach is rather a simple one however we immediately notice several drawbacks of the approac h if we recall the design requirement for optical d ata storage applications. First, the system focal length varies as the writing depth changes. Consequently, NA va ries as selection of recording layers. As a result, a varia ble aperture and tuning of laser power is needed to equalize the transverse size and modulation of index of refracti on of the micro holograms. Second, the location of the final image nonlinearly moves with respect to the movement of t he zooming element. This would impose an additional requirement on actuators for selection of writing d epth. To overcome such issues, we propose an optica l power arrangement having constant focal length as well as linear movement of zooming element. Note that, eve n being able to implement such additional features, the pro posed optical power arrangement requires only one m oving component. Thus, our approach inherits the simple i mplementation of the conventional approach. Importa ntly, such a minimum optical power arrangement is possible onl y if specific combination of power is adopted for t he zooming optical component. In this paper, first analysis of the proposed power arrangement is described. Based on the power arrangement, we discuss design of all off-the-shelf write/read optics having a constant numerical aper ture (NA) of 0.4 for a range of writing depth of 0.2 mm. Design and implementation of multi-layer and multi-bit mic ro holographic recording system employing blue lasers will be addressed.

Photopolymer films were prepared for holographic recording and fabrication of multi-dimensional holographic fluorescent patterns. The photopolymer consists of a methacrylate epoxy monomer, photoinitiator, sensitizer, binder polymer, and polyanthracene (PAnt) as a fluorophore. The high diffraction efficiency of fluorescent photopolymer film was determined through a holographic recording system as 60% for a film of 85 µm in thickness. The optimized photopolymer film was applied to fabricate 2 dimensional patterns by laser interference lithography technique and rotation method. A 2-dimensional pattern was confirmed from a fluorescent microscope, which showed crossed pattern having a line width of 0.7 μm.

A one step, single beam, holographic recording system is described which allows rapid production of graphic holograms of shadows. The factor of production time is highlighted and the limitations this can place on the creative process. A short educational workshop using the system, within a University art department is described.

Intellectual property is briefly the knowledge of somebody owns that gained importance in today’s business strategy. A patent is a license of exclusive rights granted by a state to the holder to an invention, design or process for a period of time. Intellectual Property Rights (IPR) in the field of cosmetics are often; patents, trademarks and trade secrets include formulations and production techniques. Research & Development (R&D), innovation, technology transfer, patent, establishing quality systems, branding and benchmarking are the important factors that must be considered for sustainability of the cosmetic sector. In the scope of sustainable economy and thus economic growth of a country R&D, Research & Technological Development (RTD) and innovation activities need to be encouraged and supported by effectively protected IPR systems. Negative effects of infringements of IPR to consumers, right owners, legal businesses and states can be listed basically as health risks arising from using unsafe products, decreasing the encouragement of innovation, loss of jobs and money. Especially determining the critical steps in the life cycle of products and checking their legality is efficient at fighting with counterfeiting and IPR crimes. Cooperation of competent authorities and right owners has great importance of detecting infringements of intellectual property rights and counterfeit products and conducting an effective legal process.

Despite the rapid proliferation and increased capabilities of computational fluid diagnostic algorithms, there still exists a need for experimental techniques which can provide global information in an accurate and expeditious manner for augmentation and/or verification of numerical methods. While many optical, non-intrusive techniques such as particle imaging velocimetry have been developed and refined in recent years, systems which can simultaneously extract all three-velocity components are few. We present a technique which utilizes a dual-reference-beam holographic recording and reconstruction system along with a two-step data acquisition and processing method for the determination of in- and out-of-plane velocity components form a single viewing direction. Although still under development, the method, termed holographic diffraction image velocimetry, shows promise to become a useful tool for accurate gross-field diagnostics of complex flows.

The paper proposes an equivalent optical scheme of an in-line digital holographic system for particle recording and a mathematical model that establishes a one-to-one correspondence between the dimensional and spatial parameters of a digital holographic image of a particle and the imaged particle itself. The values of the model coefficients used to determine the real size and longitudinal coordinate of a particle according to its holographic image are found by calibration. The model was tested in field and laboratory conditions to calibrate a submersible digital holographic camera designed to study plankton in its habitat. It was shown that four calibration measurements are sufficient enough to determine the model coefficients, and the developed design of the submersible digital holographic camera makes it possible to perform these measurements during the recording of each hologram. In addition, this neither requires data on the refractive index of the medium with particles nor on the parameters of the optical elements of the scheme. The paper presents the results of marine experiments in the Kara Sea and the Laptev Sea, as well as in fresh water in laboratory conditions and in Lake Baikal. The error in measuring the particle size in seawater without the use of the model is 53.8%, while the error in determining their longitudinal coordinates is 79.3%. In fresh water, the same errors were 59% and 54.5%, respectively. The error in determining the position of a particle with the use of the designed mathematical model does not exceed 1.5%, and the error in determining the size is 4.8%. The model is sensitive to changes in the optical properties of the medium, so it is necessary to perform calibration in each water area, and one calibration is quite sufficient within the same water area. At the same time, the developed design of the submersible holographic camera allows, if necessary, calibration at each holographing of the medium volume with particles.

We report an enhanced laser induced polarization switching and holography in a novel photo-reconfigurable material system that contains polymer backbone impregnated by a soft liquid crystal material. The backbone of polymer chains is reconfigurable and the surrounding movable liquid crystal molecules are reoriented collectively anchoring toward the reconfigured polymer chains, resulting in remarkable enhancement of anisotropic refractive index modulation suitable for updatable holographic recording. The dynamic polymer-liquid crystal network strengthening concept enables significant enhancement of holographic performance with controllable updatability.

Counterfeiting of valuable documents, currency and branded products is a challenging problem that has serious economic, security and health ramifications for governments, businesses and consumers all over the world. It is estimated that counterfeiting represents a multi-billion dollar underground economy with counterfeit products being produced on a large scale every year. Counterfeiting is an increasingly high-tech crime and calls for high-tech solutions to prevent and deter the acts of counterfeiting. The present review briefly outlines and addresses the key challenges in this area, including the above mentioned concerns for anti-counterfeiting applications. This article describes a unique combination of all possible kinds of security ink formulations based on lanthanide doped luminescent nanomaterials, quantum dots (semiconductor and carbon based), metal organic frameworks as well as plasmonic nanomaterials for their possible use in anti-counterfeiting applications. Moreover, in this review, we have briefly discussed and described the historical background of luminescent nanomaterials, basic concepts and detailed synthesis methods along with their characterization. Furthermore, we have also discussed the methods adopted for the fabrication and design of luminescent security inks, various security printing techniques and their anti-counterfeiting applications.

Counterfeit products are a global economic threat and include high-end parts in electronics and the automotive sector. Their counterfeit versions can lead to catastrophic failures, posing serious risks to human safety and security. Current anticounterfeiting technologies frequently degrade at the high operating temperatures of these technologies, reducing the efficacy of security features and leaving them vulnerable to tampering. Thermally stable nanocrystals are of interest for their ability to withstand extreme temperature conditions while retaining desirable size-dependent properties relevant to anticounterfeit tag creation, including their light scattering and Raman enhancement capabilities. This manuscript reports design principles for thermally stable nanocrystals capable of intense surface enhanced Raman scattering (SERS) through bimetallic nanocrystal creation. Specifically, the thermal stabilities of and SERS enhancements provided by core@shell Au@Pd nanorods of variable Pd-shell thicknesses were compared to Au nanorods, both functionalized with model Raman reporters. Notably, the thermal stability of the nanorods increased with Pd-shell thickness, while SERS enhancement was maintained at thin Pd shells. These results highlight the ability to balance thermal stability and SERS enhancement through integration of a high melting-point metal (Pd) with a strongly plasmonic metal (Au) through nanocrystal architecture.

Two-chemistry polymer systems are attractive platforms for a wide range of optical and mechanical applications due to the orthogonal chemistries of the initial thermoset matrix and the subsequent photo-initiated polymerization. This scheme allows the mechanical and optical properties of the materials to be individually addressed. However, the mechanical properties of both the initial matrix and the photopolymer system affect the performance of these materials in many applications from holography to optically-actuated folding. We present a mechanical model along with experimental demonstrations of a two-chemistry holographic photopolymer system. A three-dimensional finite element model is used to simulate the mechanical and chemical responses in time. The model uses standard material measurements to predict both large-scale deformation and more localized stress and strain. To demonstrate the magnitude of mechanical stresses possible in these materials, we show bending of thin strips with UV light activation using an optical absorber to create an intensity gradient in depth. The resulting non-uniform polymerization causes shrinkage and bending toward the light followed by swelling and bending away from the light caused by monomer diffusion. In addition to this large-scale bending, we demonstrate that the model can be used to qualitatively predict surface deformations that can be used for surface relief optical elements. The mechanical model enables understanding of shrinkage and swelling properties of a material system that affect the performance of that system over a wide range of illumination conditions.

A new photopolymer holographic recording material based on cationic ring-opening polymerization avoids limitations of conventional holographic photopolymers resulting from the free radical chemistrytypically employed. The effects of oxygen, moisture, and component characteristics on holographicrecording characteristics are described. Sensitivities greater than 0. 1 cm2/mJ and refractive index modulations greater than 5x103 are achievable with negligible changes in the physical dimensions (volume change as low as 0.4 %) of the imaged material. Linear recording is observed for exposure fluence up to20 mJ/cm2. Good Bragg selectivity consistent with the imaged thickness is observed, and both theangular response and the diffraction efficiency are stable in these materials without the need for post-imaging fixing procedures. Cationic Ring-Opening Polymerization, Photopolymer, Volume Hologram, Bragg Selectivity, Shrinkage 1. INTRODUCTION The first use of a photopolymer system to record volume-phase holograms was reported byresearchers at Hughes Aircraft Co. in 1969.1 Many other research groups have subsequently describedholographic photopolymer systems. A useful early review of this work by Torulinson and Chandross2includes a discussion on recording mechanism; a SPIE Milestone volume includes selected papers from

The growing incidents of counterfeiting and associated economic and health consequences necessitate the development of active surveillance systems capable of producing timely and reliable information for all stake holders in the anti-counterfeiting fight. User generated content from social media platforms can provide early clues about product allergies, adverse events and product counterfeiting. This paper reports a work in progresswith contributions including: the development of a framework for gathering and analyzing the views and experiences of users of drug and cosmetic products using machine learning, text mining and sentiment analysis, the application of the proposed framework on Facebook comments and data from Twitter for brand analysis, and the description of how to develop a product safety lexicon and training data for modeling a machine learning classifier for drug and cosmetic product sentiment prediction. The initial brand and product comparison results signify the usefulness of text mining and sentiment analysis on social media data while the use of machine learning classifier for predicting the sentiment orientation provides a useful tool for users, product manufacturers, regulatory and enforcement agencies to monitor brand or product sentiment trends in order to act in the event of sudden or significant rise in negative sentiment.

Holography is truly the key to three dimensions in particle image velocimetry, i.e.?the measurement of all spatial components of the velocity vector - and this over a deep measuring field. Sophisticated instruments have been designed that successfully tackle practical problems such as the low scattering efficiency of particles, the inferior depth resolution or the aberrations and distortions in the reconstruction. Furthermore, efficient strategies are introduced to interrogate the holographic storage and process the huge amount of data towards a final flow field representation. Recently, phase-sensitive metrology, familiar in many fields of experimental mechanics, has been examined for use in particle velocimetry. Suitable methods are holographic and speckle interferometry or the optical processing of data for three-dimensional correlation. While in these techniques the power of optics is unrivalled, the practical advantage of video and digital techniques over photographic recording is obvious. The electronic version of speckle interferometry (ESPI/DSPI) is a well-established method used in laser metrology and has received further exploitation for applications in flow analysis recently. Finally, the state-of-the-art of digital particle holography is reviewed to allow estimates of its future in experimental flow analysis.

Simultaneous realization of printing and holographic images has become an emerging and promising technology for optical storage and anti‐counterfeiting, which can significantly enhance the information capacity and security of an optical system. Herein, a non‐interleaved four‐channel metasurface based on opposite‐chirality‐coexisted meta‐atoms is proposed, which can simultaneously support four independent circular polarization (CP) information channels, including two near‐field printing channels and two far‐field holography channels. In addition, due to the chiral resonance properties, the operation frequencies of these four polarization channels can also be flexibly designed to simultaneously achieve polarization multiplexing and frequency multiplexing. As a proof of concept, two four‐channel metasurfaces, one of which works at a single frequency and the other works at two different frequencies, are designed and validated numerically and experimentally. It is shown in the results that two printing and two holographic images with different handedness can be stored at one frequency or two different frequencies through the flexible design of metasurface. This four‐channel metasurface provides a new avenue for the design of future photonic devices with highly integrated and multiple functionalities, and may have an advantage in diverse potential applications, such as advanced anti‐counterfeits, optical data storage, and image displays.

The resolution characteristics of in-line holographic imaging systems for application to velocity field measure- ment in turbulent and other vortical flows has been investigated experimentally. It is shown that the diameter of seed particles strongly influences the maximum size of the test volume that can be used as well as the spatial resolution of the measurement. Velocity measurements in a vortex ring flow using a two-axis holographic recording system are reported. The spatial resolution of this system is approximately 1 mm. OLOGRAPHIC imaging of flows seeded with small particles can be a useful technique for velocity field mea- surement in turbulent and other vortical flows. Several investi- gators have reported velocity measurements using holographic techniques.1'2 Two basic approaches have been proposed. In most cases in-line doubly exposed holograms of the seeded flow are obtained. The velocity is determined from the dis- placement of the particles on the reconstructed images. This approach is what we call holographic particle image velocime- try (HPIV) because it is a natural extension of planar particle image velocimetry.3 A second approach4'5 is to obtain a tempo- ral sequence of holograms. The velocity is determined by tracking individual particles as a function of time. The main advantage of HPIV compared to particle tracking techniques is that the particle displacement is determined by local analysis of the reconstructed images which results in reduced image processing requirements. Turbulent flow measurement requires a large spatial dy- namic range. This requirement becomes more severe as the Reynolds number is increased. A large spatial dynamic range requires imaging of very small particles in a large test volume. Research on in-line holographic imaging systems for particle size measurement has shown a limit to the test volume depth of 50-80 far-field distances.6'7 (The far-field distance is defined here as d2/ where d is the diameter of the particle and X the wavelength of the laser used to record the hologram.) The depth of field of the reconstructed particle images is of the order of one far-field distance.8 The depth of field of the particle image is a good measure of the spatial resolution of the velocity measurement. It follows that the resolution character- istics of the holographic imaging system can severely limit the spatial dynamic range of HPIV. In this paper we examine experimentally the resolution char- acteristics of in-line holographic imaging systems. A two-axis holographic recording system designed for high resolution ve- locity field measurements is described. Finally, velocity mea- surements in a vortex ring flow using this HPIV system are reported. The dynamic range requirements of typical HPIV recording systems dictate that the hologram be positioned at a large distance from the particles. In this case the light intensity distribution on the hologram plane is given by Fraunhofer theory9 _ , Trt/2 . 1=1- —— sin 2\z . Air2 |~ /T£/A/Tcfr) —— sin —— } \2Ji —— / —— 2\z \Xz/ |_ \\z/l XzJ '<Kdr