Self-processing photopolymer materials for versatile design and fabrication of holographic sensors and interactive holograms

Abstract

The aim of this paper is to discuss the benefits as well as the limitations of utilizing photopolymer materials in the design of holograms that are responsive to changes in their environment, such as changes in the concentration of a specific substance, temperature, and pressure. Three different case studies are presented, including both surface and volume phase holograms, in order to demonstrate the flexibility in the approach of utilizing holographic photopolymers for the design of sensors and interactive optical devices. First, a functionalized surface relief hologram is demonstrated to operate as an optical sensor for the detection of metal ions in water. The sensitivity and selectivity of the sensor are investigated. The second example demonstrates a volume transmission hologram recorded in a temperature-sensitive photopolymer and the memory effects of its exposure to elevated temperature. Finally, a pressure-sensitive reflection hologram that changes color under application of pressure is characterized, and its potential application in document authentication is described.

Temperature‐Sensitive Holograms with Switchable Memory

“…Therefore, holograms recorded in such materials can be useful as a holographic sensor or indicator. To introduce the intended functionality in polymers, different approaches are utilized, [ 2,13 ] and have been exploited for the fabrication of pressure, [ 4,13,14 ] temperature, [ 13,15 ] humidity, [ 16 ] pH, [1b,17] glucose, [ 18 ] and metal‐ion sensors. [ 13,19 ] One such approach uses a compositional variation of the photopolymer material before holographic recording.…”

“…To introduce the intended functionality in polymers, different approaches are utilized, [ 2,13 ] and have been exploited for the fabrication of pressure, [ 4,13,14 ] temperature, [ 13,15 ] humidity, [ 16 ] pH, [1b,17] glucose, [ 18 ] and metal‐ion sensors. [ 13,19 ] One such approach uses a compositional variation of the photopolymer material before holographic recording. This is typically achieved by introducing suitably selected monomers, [ 2,3 ] or nanoparticles, [ 2,3,20 ] in the material.…”

“…For example, the acrylamide (AA) monomer in the well‐documented and widely studied AA‐based photopolymer composition [1d,4b,21] has been successfully replaced in different research studies with the diacetone acrylamide (DA) monomer [ 22 ] and the N ‐isopropyl acrylamide (NIPA) monomer. [ 23 ] This achieved better response of the holograms to pressure or temperature, [ 13 ] and also lowered the toxicity of the polymer layers.…”

Application of Photopolymer Materials in Holographic Technologies

“…Applied to holographic technologies, the most widely considered in the literature are photopolymerizable acrylamide (AA/PVA) compositions [1,2], compositions with the introduction of various additives to obtain new properties, including liquid crystals [3,4] and inorganic nanoparticles [5][6][7], materials with a diffusion recording mechanism (PQ/PMMA) [8,9]. The processes in materials, their properties, as well as the properties of holographic elements for various practical applications, including data storage [10,11], sensors [12], protective elements [13], and elements of holographic solar concentrators [14,15] are studied.…”

Outdoor performance evaluation of a holographic solar concentrator optimized for building integration

“…with set room temperature and humidity) differs from its performance outdoors, with varying ambient conditions throughout the day and the year and depending on the location. This is because the photosensitive material where the HOE is recorded may also be sensitive to these factors [13][14][15][16][17]; in fact they may be used as sensors [13,14]. Some authors have investigated the response of HOEs recorded on Bayfol ® HX photopolymer while being at cryogenic temperatures [18], but there is no research analyzing the behavior of the hologram at temperatures that could be achieved outdoors.…”