Thermally assisted recording of holographic gratings in semicrystalline azobenzene-containing polymers

Abstract

We examine optically induced birefringence in semicrystalline azopolymer films that are held at glass-transition temperature Tg. The birefringence increases markedly after interception of the pump beam; the saturation value depends on exposure time. In addition, the induced birefringence is completely erased by irradiation with a circularly polarized beam at Tg. Using this thermally assisted method, we demonstrate the holographic recording of a test image. The intensity of the diffracted beam also increases after interception of the writing beams. Furthermore, the retrieved image is found to have a resolution of approximately 30 lp/mm. This resolution is comparable with that of the optical setup that is used. Accordingly, the thermally assisted recording by use of semicrystalline azopolymers is a promising method for reversible holographic storage.

Reversible Control of Thermally Enhanced Birefringence in Semicrystalline Azo Polymer Films with Polarized Light

“…We have reported that a thermally assisted recording can enhance Fourier transform holograms in semicrystalline azo polymer films. 19) Photocontrollability would, therefore, enable the enhancement of Fourier transform holograms thermally.…”

Rewritable High-Density Optical Recording on Azobenzene Polymer Thin Film

“…1,2) Azobenzene functionalized polymers are known to allow large-scale mass transport upon light irradiation and to result in the formation of surface relief. Although technical development of high-density data storage based on magnetic media is undoubtedly conspicuous, it is stated that there is a practical upper limit on recording density of about 1 TB/inch 2 .…”

Holographic storage and multiplexing in azopolyester blends using low energy pulses down to 2 ms

“…In particular, thermal treatments as well as blue and red light illuminations can modify that response in a significant way. [13][14][15][30][31][32] We have tried several conditions, and selected those that give high and stable values for the diffracted intensity of volume holographic gratings. After an initial annealing of the films at 80 C for 1 min, they were irradiated for 5 s with a single circularly polarized 488 nm light beam (2 W/cm 2 ) to erase any previously stored information.…”