Study on the recording stability enhancement of polymer-based 3D optical data storage materials

Abstract

Photopolymers and photorefractive polymers have been exploited in a variety of applications requiring versatile holographic storage media, such as high-density data storage, holographic optical elements, and waveguides. Although other holographic recording materials, particularly inorganic photorefractive crystals, have been used to develop these technologies, it is widely regarded that the high diffraction efficiency, high sensitivity, low cost, and versatility of polymeric materials would enable more wide spread commercial applications of holography. However, both of the two candidates have several problems to be solved for practical application. For both of them, inherent instability of the amorphous organic materials is a crucial demerit compared with inorganic holographic materials. The main objective of this thesis is focused on the stability of polymeric recording materials, including photopolymer and photorefractive polymer. In this thesis, phase stability and recording stability of the photopolymer based on poly(methyl methacrylate-co-methacrylic acid), acryl amide, triethanolamine, and photosensitizer was studied with the aim to solve the problems associated with the acrylate-based photopolymer. In order to enhance the phase stability and recording stability of photopolymer, we tried to control the miscibility between constituents by the modification of the structure of polymer matrix without reducing the refractive index difference $(\Delta n)$. In addition to the miscibility control of the photopolymer, we demonstrated a novel organic-inorganic hybrid photopolymer with the aim to reduce the volume shrinkage without sacrificing energetic sensitivity and optical quality of photopolymer. Surface-photoreactive nanoparticles was synthesized and doped into the photopolymer. As another objective of this thesis, recording stability and photorefractivity for the photorefractive polymer composite based on poly(vinyl carbazole, PVK) as a photoconducting p...