scholarly journals Zero Spatial Frequency Limit: Method to Characterize Photopolymers as Optical Recording Material

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Sergi Gallego ◽  
Andrés Márquez ◽  
Manuel Ortuño ◽  
Cristian Neipp ◽  
Inmaculada Pascual ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Data Storage ◽  
Direct Method ◽  
Optical Recording ◽  
Optical Processing ◽  
Optical Elements ◽  
Recording Material ◽  
The University ◽  
A Direct Method ◽  
Processing Group

Photopolymers are useful for different holographic applications such as holographic data storage or diffractive optical elements. However, due to the presence of two different phenomena, polymer formation and monomer diffusion, it is difficult to characterize each parameter independently. We propose a direct method based on zero spatial frequency recording, to eliminate the diffusion influence, and on interferometric techniques, both in transmission and in reflection, to obtain quantitative values of shrinkage, polymerization rate, polymer refractive index and relation between intensity and polymerization, and so forth, This method has been implemented in the Holography and Optical Processing Group from the University of Alicante to characterize different photopolymers. In this paper, we present a compilation of the results obtained with this method for different photopolymers and we compare their characteristics.

scholarly journals A Review of Polarization-Sensitive Materials for Polarization Holography

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5562
Author(s):  
Yueyang Zhai ◽  
Li Cao ◽  
Ying Liu ◽  
Xiaodi Tan
Keyword(s):  
Data Storage ◽  
High Performance ◽  
High Capacity ◽  
Polarization Holography ◽  
Optical Elements ◽  
Recording Material ◽  
Potential Applications ◽  
Capacity Data ◽  
Polarization Of Light

Polarization holography has the unique capacity to record and retrieve the amplitude, phase, and polarization of light simultaneously in a polarization-sensitive recording material and has attracted widespread attention. Polarization holography is a noteworthy technology with potential applications in the fields of high-capacity data storage, polarization-controlled optical elements, and other related fields. The choice of its high-performance materials is particularly important. To further develop polarization holography applications and improve the quality of the information recorded (i.e., material sensitivity and resolution), a deeper understanding of such materials is needed. We present an overview of the polarization-sensitive materials, which introduced polarization holographic technology and the development of polarization holographic materials. The three main types of polarization holographic materials are described, including azopolymer materials, photopolymer material, and photorefractive polymer material. We examine the key contributions of each work and present many of the suggestions that have been made to improve the different polarization-sensitive photopolymer materials.

scholarly journals Diffractive Optical Elements with a Large Angle of Operation Recorded in Acrylamide Based Photopolymer on Flexible Substrates

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Hoda Akbari ◽  
Izabela Naydenova ◽  
Lina Persechini ◽  
Sean M. Garner ◽  
Pat Cimo ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
High Efficiency ◽  
Large Angle ◽  
Optical Recording ◽  
Holographic Recording ◽  
Angular Range ◽  
Optical Elements ◽  
Lens Element ◽  
Single Lens ◽  
Exposure Energy

A holographic device characterised by a large angular range of operation is under development. The aim of this study is to increase the angular working range of the diffractive lens by stacking three layers of high efficiency optical elements on top of each other so that light is collected (and focussed) from a broader range of angles. The angular range of each individual lens element is important, and work has already been done in an acrylamide-based photosensitive polymer to broaden the angular range of individual elements using holographic recording at a low spatial frequency. This paper reports new results on the angular selectivity of stacked diffractive lenses. A working range of 12° is achieved. The diffractive focussing elements were recorded holographically with a central spatial frequency of 300 l/mm using exposure energy of 60 mJ/cm2at a range of recording angles. At this spatial frequency with layers of thickness 50 ± 5 µm, a diffraction efficiency of 80% and 50% was achieved in the single lens element and combined device, respectively. The optical recording process and the properties of the multilayer structure are described and discussed. Holographic recording of a single lens element is also successfully demonstrated on a flexible glass substrate (Corning(R) Willow(R) Glass) for the first time.

Linear Least-Squares Computations Using Givens Transformations

1983 ◽  
Vol 37 (4) ◽  
pp. 225-233 ◽  
Author(s):  
J. A. R. Blais
Keyword(s):  
Least Squares ◽  
Error Estimates ◽  
Data Storage ◽  
Computational Efficiency ◽  
Numerical Stability ◽  
Direct Method ◽  
Linear Least Squares ◽  
Normal Equations ◽  
Estimation Problems ◽  
A Direct Method

Givens transformations provide a direct method for solving linear least-squares estimation problems without forming the normal equations. This approach has been shown to be particularly advantageous in recursive situations because of characteristics related to data storage requirements, numerical stability and computational efficiency. The following discussion will concentrate on the problem of updating least-squares parameter and error estimates using Givens transformations. Special attention will be given to photogrammetric and geodetic applications.

scholarly journals Evaluation of the cytotoxic and genotoxic effect of garlic (Allium sativum L.) root cells after exposure to contaminant solution

2020 ◽  
Vol 13 (3) ◽  
pp. 6
Author(s):  
L. P. N. Ramos ◽  
L. S. D. Nascimento ◽  
J. S. Lima ◽  
C. B. M. Farias ◽  
V. S. Mello ◽  
...  
Keyword(s):  
Indirect Method ◽  
Allium Sativum ◽  
Chemical Nature ◽  
Direct Method ◽  
Root Cells ◽  
Mato Grosso ◽  
Index Analysis ◽  
Mutagenic Effects ◽  
The University ◽  
A Direct Method

Water contamination is much more common than imagined, because it is practically impossible today to have an ecosystem that has not suffered directly or indirectly from humans. Studies with the aim of genotoxicity and mutagenesis use bioindicators as the basis of tests, the most used are from the Allium ssp family. When we mention cytogenetic damage, the intensity depends mainly on the degree of exposure, quantity, chemical nature and of the possible combinations between the contaminants, also influenced by the characteristics and conditions of the environment in which the organisms considered bioindicators are submitted. The present work has the objective of analyzing the cytotoxic, genotoxic and mutagenic effects induced by contaminating material that cause chromosomal alterations by means of mitotic index analysis using as bioindicator Allium sativum (garlic). The experiment was carried out at the Laboratory of Cytogenetics and Culture of Vegetable Tissues at the University of the State of Mato Grosso (UNEMAT) at the Alta Floresta Campus - MT. The soil was collected and stored separately using 200 grams of each sample with three treatments: surface, 20 cm and 40 cm deep, making a tea with 200 ml of distilled water and then measuring the pH. Using a direct method where the bioindicator is submitted directly to the tea solution, awaiting the emission of roots, and the indirect method, where the bioindicator is submitted first, the stimulation of root formation for 72 hours and then is submitted to contaminating solution. The plates readings to observe the interior of the cell using crushing techniques were performed in 24, 48 and 72 hours of experiment (indirect method) and 24 hours (direct method, also measuring the roots). With the results, we can state that the material used as pollutant (soil sample) has a cytotoxic and genotoxic potential in the bioindicator material, presenting high potential in the cell cycle induction, provoking various chromosomal aberrations.

New Optical Recording Material for Data Storage

1983 ◽  
Author(s):  
Yoshio Aoki ◽  
Kenjirou Watanabe ◽  
Tomoya Oyama ◽  
Noboru Satou ◽  
Senri Miyaoka
Keyword(s):  
Data Storage ◽  
Optical Recording ◽  
Recording Material

scholarly journals Plastic waste to fuels by hydrocracking at mild conditions

2021 ◽  
Vol 7 (17) ◽  
pp. eabf8283
Author(s):  
Sibao Liu ◽  
Pavel A. Kots ◽  
Brandon C. Vance ◽  
Andrew Danielson ◽  
Dionisios G. Vlachos
Keyword(s):  
Direct Method ◽  
Acid Sites ◽  
Liquid Fuels ◽  
High Yield ◽  
Tandem Catalysis ◽  
Hy Zeolite ◽  
Environmental Threat ◽  
Single Use ◽  
Initial Activation ◽  
A Direct Method

Single-use plastics impose an enormous environmental threat, but their recycling, especially of polyolefins, has been proven challenging. We report a direct method to selectively convert polyolefins to branched, liquid fuels including diesel, jet, and gasoline-range hydrocarbons, with high yield up to 85% over Pt/WO3/ZrO2 and HY zeolite in hydrogen at temperatures as low as 225°C. The process proceeds via tandem catalysis with initial activation of the polymer primarily over Pt, with subsequent cracking over the acid sites of WO3/ZrO2 and HY zeolite, isomerization over WO3/ZrO2 sites, and hydrogenation of olefin intermediates over Pt. The process can be tuned to convert different common plastic wastes, including low- and high-density polyethylene, polypropylene, polystyrene, everyday polyethylene bottles and bags, and composite plastics to desirable fuels and light lubricants.

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