Analysis of the Imaging Characteristics of Holographic Waveguides Recorded in Photopolymers

Abstract

<jats:p>In this work, we study the imaging characteristics of an optical see-through display based on a holographic waveguide. To fabricate this device, two transmission holograms are recorded on a photopolymer material attached to a glass substrate. The role of the holograms is to couple the incident light between air and the glass substrate, accomplishing total internal reflection. The role of noise reflection gratings and shrinkage on the imaging characteristics of the device will be also explored. The holograms (slanted transmission gratings with a spatial frequency of 1690 lines/mm) were recorded on a polyvinyl alcohol acrylamide holographic polymer dispersed liquid crystal (HPDLC) material. We will show that sufficient refractive index modulation is achieved in the material, in order to obtain high diffraction efficiencies. We will demonstrate that the final device acts as an image formation system.</jats:p>

Tunable Waveguides Couplers Based on HPDLC for See-Through Applications

“…Due to the high viscosity of this monomer the solution should be stirred with a stick to obtain a transparent mixture again. From the solution 0 (solt 0) studied in previous papers [ 8 , 20 ], we have not detected any significant variation of the transmission efficiency, TE, under electric field between the two glass substrates. Therefore, for solution 1 (solt 1) we have increased the monomer concentration and LC.…”

“…It is a mixture of 4-cyanobiphenyls with alkyl chains of different lengths. It has an ordinary refractive index 𝑛 0 = 1.520 and a difference between extraordinary and ordinary index Δ𝑛 = 0.250 [ 20 ]. The liquid crystal concentration was set at 28 wt%, for solution 0, see Table 1 , as the starting point for component optimization and remained practically unchanged during this process.…”

Recent Advances in The Polymer Dispersed Liquid Crystal Composite and Its Applications

“…Morphology and diffraction properties of the grating depend upon writing set-up, materials, diffusion rate, curing conditions and the phase separation process Typical morphology, the working principle and electro-optical properties of HPDLCs are thoroughly elaborated in chapter 5 of the recently published book [ 109 ]. Promising applications of HPDLCs include diffraction gratings (DGs), polymer slices (POLICRYPS), waveguides, autostereoscopic image splitter, three-dimensional (3D) data storage and photonic crystals [ 110 , 111 , 112 , 113 , 114 , 115 , 116 , 117 ].…”

15.2: Design and Realization of Full‐Color VHG Holographic Waveguide Display

“…Dry processing, ease of storing information, high diffraction efficiency, good spatial frequency response etc. make them fit for different holographic applications like data storage, information processing and display purposes [2][3][4]. High refractive index modulation, good light sensitivity, real-time image development, high optical quality and low cost are the important properties of photopolymers enabling them to occupy an outstanding position as holographic recording media.…”