Optical data storage has been widely used in certain consumer applications owing to its passive and robust nature, but has failed to keep with larger industry data storage needs due to the lack of capacity. Many alternatives have been proposed and developed, such as 3D data storage using two-photon absorption that require complex and dangerous laser systems to localize the bits. In this paper, we present a method for localizing bits using a CW 405nm laser diode, in a multilayered polymer film. Data is stored by photobleaching a fluorescent dye, and the response of the material is nonlinear, despite the CW laser and absorption in the visible region. This is achieved using sub-μs pulses from the laser initiating a photothermal effect. This writing method, along with the inexpensive roll-to-roll method for making the disc, will allow for terabyte-scale optical discs using conventional commercial optics and lasers.
New approaches for optical data storage (ODS) applications are needed to meet the future requirements of applications
in multimedia, archiving, security, and many others. Commercial data storage technologies are moving to threedimensional
(3D) materials, but the capacity is limited by the fabrication cost and the number of layers that can be
addressed using the reflection-based storage mechanism. We demonstrate here storage systems based on co-extrusion of
multilayer (ML) films that can overcome these problems. The organic roll-to-roll films produced can easily be produced
hundreds of meters in length, in a far simpler and cheaper manner than current manufacturing methods such as spin
coating and lamination. The medium consists of alternating active and buffer layers, and data storage is demonstrated by
writing images in 23 layers of 78 μm thick films by fluorescence (FL) quenching of an organic dye. The areal data
resolution is at the diffraction limit of the CW Blu-ray (BR) laser employed, and the co-extrusion technique allows for
small layer spacings, leading to a total bit density 1.2 Tb/cm3. We anticipate materials already demonstrated successful
for 3D ODS will be adapted to this technique, as well as new systems developed, to take full advantage of this medium.
Recently a melt-processed blend of
1,4-bis(α-cyano-4-octadecyloxystyryl)-2,5-dimethoxybenzene (C18-RG) dye and
polyethylene terephthalate glycol (PETG) has been demonstrated as a promising 3-dimentional optical data storage
(ODS) medium 1. ODS in this novel system relies on the laser-induced switching of the aggregation state of the excimerforming
fluorescent dye in the inert host polymer. Here we investigate the mechanism and the time scales involved in the
writing process. The optical writing was realized by the laser-induced localized excimer to monomer conversion and was
characterized by the emergence of the monomer fluorescence. We obtained the dependence of the excimer to monomer
conversion on the writing time. Our result indicates that the effective optical writing time is controlled by heating and
cooling time of the host polymer and the excimer-to-monomer conversion time. The effective laser writing time, under
the specific writing conditions employed in our experiments, is on the order of 10 ms.