Formation of temperature dependable holographic memory using holographic polymer-dispersed liquid crystal

Abstract

Grating devices using photosensitive organic materials play an important role in the development of optical and optoelectronic systems. High diffraction efficiency and polarization dependence achieved in a holographic polymer-dispersed liquid crystal (HPDLC) grating are expected to provide polarization controllable optical devices, such as the holographic memory for optically reconfigurable gate arrays (ORGAs). However, the optical property is affected by the thermal modulation around the transition temperature (T(ni)) that the liquid crystal (LC) changes from nematic to isotropic phases. The temperature dependence of the diffraction efficiency in HPDLC grating is discussed with two types of LC composites comprised of isotropic and LC diacrylate monomers. The holographic memory formed by the LC and LC diacrylate monomer performs precise reconstruction of the context information for ORGAs at high temperatures more than 150°C.

Effect of Noncovalent Interaction of a Polymer-Dispersed Liquid Crystal for Interferometric Applications over a Range of Low Frequencies

“…The mixture film turns transparent when the refractive indexes of the UV curable agent and the liquid crystal become almost the same. Due to this adjustability trait, PDLCs have attracted notable attention because of their potential in a broad range of applications, in optical shutters and switchable windows, − switchable smart glass using UV-initiated cationic polymerization, a liquid crystal/polymer composite film with programmable electro-optical properties, doped LC devices, − self-powered switchable solar windows, holographic applications, − and autostereoscopic display. , Porous uniformity is also well-explained for nucleated LC droplets aiming rubbing polyimide layers with anchoring energy greater than 1 × 10 –4 J/m 2 . The dielectric properties of PDLCs were thoroughly studied by Kelly and Seekola in 1990; this outlines that there is an unambiguous relationship between conduction in the liquid crystal droplets and operating frequencies.…”

Numerical Analysis of H-PDLC Using the Split-Field Finite-Difference Time-Domain Method

“…Moreover, H-PDLCs have additional well-known properties such as birefringence and optical anisotropy, amongst others. As a result of all these properties, H-PDLCs are of great interest due to the possibility of applying them to many optical systems such as electrically-switchable [3,4] and tunable photonic devices [5], wavelength filters [6], 3D displays [7,8], holographic waveguides [9], optical memories [10] and photonic crystals [11,12,13].…”

Spatial Frequency Responses of Anisotropic Refractive Index Gratings Formed in Holographic Polymer Dispersed Liquid Crystals

“…Such electro-optic HPDLCs consist of LCs incorporated into photopolymer followed by holographic polymerization that represents a fast and relatively simple way of fabricating multi-dimensional refractive index grating structures for electrically switchable and tunable photonic devices [7]. They have been used for wavelength filters, 3D displays, hyperspectral imaging, optical beam switching/control devices, sensors, lasers, optical memory and photonic crystals [8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24]. …”