Optical data storage in photochromic compounds

Abstract

The future of optical data storage and the search for next generation high-density technologies have become a topic of lively debate. Three dimensional (3D) optical data storage, a relatively new technique which enables hundredslayer data recording in a hard memory, seems a viable candidate for this role. In this work, we report on 3D optical data storage in photochromic compounds. The recording medium used in the experiments was a photochromic diarylethenes derivative embedded in different host polymers. Multi-photon processes capability of triggering photochemical reactions and physical changes with micrometer-sized resolution in three dimensions offers a wellsuited means to achieve volumetric storage densities. A commercial microscope coupled to pulsed NIR and CW lasers have been used to write, read and erase data in our prototype memories. Information was recorded within the volume of the media via a multi-photon process achieving high localized photoconversion and the fluorescence emission from the photoconverted molecules when excited by a 405 nm laser diode was the readout signal. It is also shown that data recorded in such a medium can be selectively erased by irradiating with 514 nm CW laser light giving the chance to write new data in the formerly used memory space. These storage media, thus, have good potentials to achieve volumetric storage of data although they certainly deserve further optimization work to achieve high number of superposed layers and to assure durability of the written data under readout conditions.

Tuning the π-bridge of quadrupolar triarylborane chromophores for one- and two-photon excited fluorescence imaging of lysosomes in live cells

“…For this reason, two-photon absorption enables excitation of molecules within a very small volume (∼femto liter) at the focus of a laser beam, which is useful for many applications. There is thus a strong demand for efficient two-photon absorption dyes for microfabrication,54–57 three-dimensional data-storage,58–60 optical power limiting,61–63 laser up-conversion,64,65 photodynamic therapy66,67 and biological imaging 47,68–70. Especially for the latter application, relatively few small organic molecules have been studied, as they need to be highly specific for their biological target, highly photostable, water-stable and at least somewhat water-soluble to stain cells and tissues.…”

Characterization of fatigue resistance in photochromic composite materials for 3D rewritable optical memory applications

“…5(b), where a cross section of the drop-casted sample along the z-direction shows a series of vertically aligned photoconverted spots throughout the depth of the sample. The sizes of the laser spots have FWHM of 8.7 m in the longitudinal direction, and of 2.2 m in the transversal one [30]. The displacement along the vertical direction between the spots was 5 m. The picture reported shows a sequence of 16 spots.…”

An Analytical Model to Determine the Optimal System for a Fluorescence Based Multilayered 3D Optical Data Storage System

“…Confocal detection can help this solve this problem. Confocal detection uses a small pinhole to resolve signal along the axial direction from densely packed data layers [27,28]. Data storage mechanisms that create localized optical changes to the material either change their fluorescence properties or refractive index (reflection).…”