Spatial frequency response of Acrylamide based holographic photopolymer (original) (raw)

Development of a Panchromatic Acrylamide Based Photopolymer for Multicolour Reflection Holography

Applied Optics, 2010

The development of a panchromatic acrylamide based photopolymer (ABP) for holographic recording application is presented. The scattering of the recording medium was characterised by measuring the Bidirectional Scattering Distribution Function (BSDF). The dynamic range in reflection mode of recording was evaluated by measuring the diffraction efficiencies of the holographic gratings recorded individually at 633nm, 532nm, and 473nm wavelengths at spatial

Development of a panchromatic acrylamide-based photopolymer for multicolor reflection holography

Applied Optics, 2010

The development of a panchromatic acrylamide based photopolymer (ABP) for holographic recording application is presented. The scattering of the recording medium was characterised by measuring the Bidirectional Scattering Distribution Function (BSDF). The dynamic range in reflection mode of recording was evaluated by measuring the diffraction efficiencies of the holographic gratings recorded individually at 633nm, 532nm, and 473nm wavelengths at spatial frequencies of 4200 l/mm, 5000 l/mm and 5700 l/mm respectively. Spectral characterisation of the reflection gratings recorded using a combined single RGB beam was carried out and the reconstructed wavelengths were monitored and compared with the recording wavelengths. The recorded and the reconstructed wavelengths were plotted as points on the CIE chromaticity diagram in order to reveal the shifts due to material shrinkage in the corresponding RGB wavelengths. Finally reflection holograms of an object were successfully recorded at all the three primary wavelengths. The results represent a strong confirmation that this acrylamide based photopolymer can be used as a panchromatic recording material and can be employed in future commercial holographic applications.

Holographic recording in acrylamide photopolymers: thickness limitations

Applied Optics, 2009

Holographic recording in thick photopolymer layers is important for application in holographic data storage, volume holographic filters and correlators. Here, the characteristics of acrylamidebased photopolymer layers having thickness from 250 µm to 1-mm were studied. For each layer thickness samples with three different values of absorbance were studied. By measuring both the first order diffraction efficiency growth of holographically recorded gratings and studying the diffraction patterns obtained, the influence of scattering on the diffraction efficiency of thick volume holographic gratings was analyzed. It was observed that above a particular thickness and absorbance, the first order diffraction efficiency significantly decreased because of increased holographic scattering. From the first order diffraction efficiency dependence on the samples absorbance and thickness it is possible to choose photopolymer layer properties that are suitable for a particular holographic application. This study was carried out in order to determine the highest layer thickness that could be used in phase code multiplexed holographic data storage system utilizing thick photopolymer layers as a recording medium.

Optical and holographic characteristics of photopolymer layers

2009

In the present work the optical and holographic characteristics of acrylamide-based photopolymer layers are studied. For the first time the refractive index change of a liquid acrylamide photopolymer due to exposure at 532 nm is obtained using a critical angle laser micro-refractometer. The 30 µm thick solid photopolymer films are prepared by casting on glass substrates. Bragg holographic gratings with spatial frequencies of 710 mm -1 , 1050 mm -1 and 1600 mm -1 are recorded using a diode laser operating at 532 nm wavelength. The diffraction efficiency dependence on the exposure energy is investigated. The obtained results are compared with the Stetson holographic recording method, where two gratings are simultaneously recorded in the same location with spatial frequencies 2020 mm -1 and 3670 mm -1 , using a totally reflected reference wave from the airphotopolymer interface. Despite the fact that in the second method the two gratings share the same dynamic range, higher diffraction efficiencies are observed.

Multiplexing holograms in an acrylamide photopolymer

Proceedings of Spie the International Society For Optical Engineering, 2006

A peristrophic multiplexing method is used to store various diffraction gratings at the same spot in the material. This material is formed of acrylamide photopolymers which are considered interesting materials for recording holographic memories. They have high diffraction efficiency (ratio between diffracted and incident beams), high energetic sensitivity and optical quality, and developing processes are not necessary. In this work, the photopolymer is composed of acrylamide (AA) as the polymerizable monomer, triethanolamine (TEA) as radical generator, N,N'methylene-bis-acrylamide (BMA) as crosslinker, yellowish eosin (YE) as sensitizer and a binder of polyvinyl alcohol (PVA). The layers of material obtained are approximately 1 mm thick. Using holographic recording schedules, the exposure energy each hologram should receive in order to achieve uniform diffraction efficiency is optimized. The purpose of these recording schedules is to enable full advantage to be taken of the whole dynamic range of the material and to share it between the individual holograms. The Scheduled Exposure Method (SEM) and the Incremental Exposure Method (IEM) are the two multiplexing schedules used to determine the recording times. Having determined these times, the results obtained with both methods are compared to ascertain which method enables the greatest number of holograms to be recorded with the highest, most uniform diffraction efficiencies.

Holographic patterning of acrylamide-based photopolymer surface

Articles, 2005

The patterning of an acrylamide-based photopolymer surface by holographic recording is studied. The patterns are induced by light alone and no post-processing is required. Periodic surface modulation is observed in addition to a volume phase grating. An investigation has been carried out using white light interferometry into the dependence of the amplitude of the photoinduced surface relief modulation on the spatial frequency, intensity of recording and sample thickness. The observed dependencies indicate that the diffusion of material during the holographic recording plays a major role in surface relief formation. The possibility for inscription of surface relief patterns opens the door to at least two new applications for this photopolymer: fabrication of diffractive optical elements and biosensors.

Thickness variation of self-processing acrylamide-based photopolymer and reflection holography

2001

There are many types of holographic recording material. The acrylamide-based recording material examined here has one significant advantage: it is self-processing. This simplifies the recording process and enables holographic interferometry to be carried out without the need for complex realignment procedures. However, the effect that the polymerization process has on the grating thickness must be examined. This question is fundamental to the material's use in holographic optical elements, as thickness variations affect the replay conditions of the produced elements. This paper presents a study of this thickness variation and reports for the first time the production of reflection holographic gratings in this material.

Comparison of diffuse-object holograms and holographic gratings stored on acrylamide photopolymers

Optik - International Journal for Light and Electron Optics, 2002

In this study the diffraction efficiency of diffuseobject holograms is compared with that of holographic gratings for a constant beam ratio and different intensities in order to analyzed the storage and reconstruction process with the same wavelength. When we work with the same wavelength in the register and reconstruction process, the refraction index modulation decreases. The material used is a photopolymer based on acrylamides, consisting of acrylamide as monomer, yellowish eosin as sensitizer and triethanolamine as radical generator, all on a matrix of polyvinyl alcohol.