Refractive index change in photochromic diarylethene derivatives and its application to optical switching devices

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Chemistry., 1997-05, Vol.105 (1), p.75-81
• Main Authors: Hoshino, Mitsutoshi, Ebisawa, Fumihiro, Yoshida, Takashi, Sukegawa, Ken
• Format: Article
• Language: English
• Subjects: Diarylethene derivatives; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Holographic recording materials; optical storage media; Optical materials; Optical switching device; Optics; Photochromic; Physics; Polymers and organics; Refractive index change
• ISSN: 1010-6030; 1873-2666
• DOI: 10.1016/S1010-6030(97)00024-5

The refractive index change of photochromic diarylethene derivatives in solid polymer was studied with a view to fabricating an optical switching device. The reaction time required for a symmetric diarylethene photochromic compound in a copolymer of fluoroethyl methacrylate and methyl methacrylate (film thickness: 10 μm) was 20–30 s when exposed to UV light (intensity: 5.3 mW cm −2 at 350 nm) to form a closed ring and about 10 s with visible light (intensity: 3.7 mW cm −2 at 500 nm) to form an open ring. The refractive index change at 1.30 μm, measured with a prism coupler, was 0.0005 per 10 wt.% of diarylethene photochromic compound. The iteration number of the photochromic reactions in the polymer film decreased in the following order: symmetric, asymmetric diarylethene and acid anhydride. We propose a new type of self-holding optical switch combining a heat stable photochromic material with silica planar lightwave circuits.