Chapter 5 Holography and Holographic Interferometry via Photopolymer Film Austin Giordano, Lionel T. Keene, Ryan Norris, and Fu-Pen Chiang Abstract A new method of performing holography and holographic interferometry is proposed, whereby the film does not have to be developed in the manner that traditional film needs to be developed. This is done by implementing a photopolymer film, a film that develops via a reaction diffusion-driven photo-polymerization process. The utilization of photopolymer film rapidly simplifies the process of performing holography and holographic interferometry as it removes the wet development process that was previously required in holography. Keywords Holography · Holographic interferometry · Photopolymer · Plate bending · Displacement contours 5.1 Introduction Holographic film has the capability to store the interference pattern of waves of light. Once developed using a reference beam, the holographic film can reconstruct the image of the object that was used to create the hologram. Many have applied holography and holographic interferometry to study mechanics [1–3]. A wide variety of materials have been implemented in holography [4, 5] recently; a new holographic film material has been developed by Bayer named Bayfol HX photopolymer [6]. Bayfol HX photopolymer has allowed for a simpler process of producing holograms. Bayfol HX photopolymer produces a real-time hologram due to the development process; high index monomers dissolved in the PUR matrix polymerize when exposed to a holographic interference pattern. After the monomers have linked together to produce the fringes of the hologram, the film is exposed to white light to fix and bleach the film and complete the development procedure. This process removes the difficulty associated with the wet chemistry used in the development of silver halide film traditionally used in holography. The live development process of photopolymer film allows for the film to be exposed to light until it is fully developed; due to the nature of the monomers, there is no way in which the film can be overdeveloped. Photopolymer film additionally allows for the film to be left in place during development, and then the object can be deformed or moved to perform holographic interferometry. In this paper, usage of the new photopolymer material to obtain holograms and performing holographic interferometry is presented. A simple plate bending is used to depict the capability of the new type of film. 5.2 Experimental Procedures The system used for the data acquisition is as shown in Fig. 5.1. A laser beam is split into two separate beams, the reference and object beam, using a beam splitter. Then the object beam is expanded and illuminates the specimen of interest; simultaneously the reference beam is expanded and illuminates the holographic film. The laser power is tuned using a A. Giordano ( ) · R. Norris · F.-P. Chiang Department of Mechanical Engineering, State University of New York at Stony Brook, Stony Brook, NY, USA e-mail: austin.giordano@stonybrook.edu; fu-pen.chiang@stonybrook.edu L. T. Keene Nondestructive Characterization Institute, Lawrence Livermore National Laboratory, Livermore, CA, USA © The Society for Experimental Mechanics, Inc. 2021 M.-T. Lin et al. (eds.), Advancement of Optical Methods & Digital Image Correlation in Experimental Mechanics, Conference Proceedings of the Society for Experimental Mechanics Series, https://doi.org/10.1007/978-3-030-59773-3_5 51
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