Optical image processing using the photoinduced anisotropy of pyrrylfulgide

Abstract

A synthesized photochromic compound-pyrrylfulgide--is prepared as a thin film doped in a polymethylmethacrylate (PMMA) matrix. Under irradiation by UV light, the film converts from the bleached state into a colored state that has a maximum absorption at 635 nm and is thermally stable at room temperature. When the colored state is irradiated by a linearly polarized 650 nm laser, the film returns to the bleached state; photoinduced anisotropy is produced during this process. Application of optical image processing methods using the photoinduced anisotropy of the pyrrylfulgide/PMMA film is described. Examples in non-Fourier optical image processing, such as contrast reversal and image subtraction and summation, as well as in Fourier optical image processing, such as low-pass filtering and edge enhancement, are presented.

Holographic Image Storage with a 3-Indoly-Benzylfulgimide/PMMA Film

“…These are the two spectrally separated photochromic forms, whose molecular formulas are shown in Fig.9. In this film we also found the photo-induced anisotropy property [4] . The absorption of the C-form (A C (λ)) and E-form film (A E (λ)) were measured using a UV-VIS-IR spectrophotometer (UV-3101PC, Shimadzu Inc., Japan), which were shown in Fig.10a.…”

“…We found that there exists photo-induced anisotropy in fulgide-doped polymeric films [4] , which can be used in polarization holography application. When the colored states are irradiated by a linearly polarized 650 nm laser, the films returns to the bleached states and photo-induced anisotropy is produced during this process.…”

“…When the colored states are irradiated by a linearly polarized 650 nm laser, the films returns to the bleached states and photo-induced anisotropy is produced during this process. The mechanism of photoinduced anisotropy in the fulgide films is the following [4] : anisotropic absorbing molecules of fulgide are immobilized randomly in the PMMA polymeric matrix, which shows isotropic characteristic at the initial state; when the sample is irradiated by linearly polarized light photo-selection of molecules take place. Molecules with long axes parallel to the exiting light polarization direction absorb the light strongly and turn to the other form very quickly, whereas those with long axes perpendicularly orientated to exiting light polarization have low absorption and stay at the initial form.…”

Optical Fourier techniques for medical image processing and phase contrast imaging

“…Simply by placing a polarizer sheet at the Fourier plane, Ferrari et al demonstrated phase visualization and edge enhancement [27]. Most recently, Menke et al demonstrated optical image processing using photoinduced anisotropy property of pyrrylfulgide [28].…”

“…In bR, switching between B and M states are used to create the photoinduced anisotropy. Similarly in azobenzene molecules, trans-cis isomerization states are exploited, whereas pyrrylfulgide operates between its two states -bleached state (E-form) and colored state (C-form) [28].…”