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Recently, many kinds of biological materials attract attention not only for bio- and medical applications but also for electronic and/or photonic devices as new renewable resources. Biomaterials such as DNA are basically insulating and transparent in original forms not being adequate for such industrial application. The drawbacks of DNA was overcome by complexation with other organic molecules in various fashions thanks to its highly complex and organized structure. DNA, only soluble in water, can be coupled to cationic surfactants, transforming it into hydrophobic polymer complex which can be easily dissolved in organic solvents and processed into thin films accompanying other compounds. Previously, we fabricated the bilayer devices composed of PMMA layer containing an azobenzene derivative and a cyanine dye doped DNA complex layer, and demonstrated laser wavelength tuning. Recently, we prepared single layer films composed of DNA-CTMA, azo polymer having push-pull substituents where laser dye were doped later with an immersion method. By choosing adequate combination of laser and azo dyes in order to eliminate or reduce the reabsorption of amplified photons, we have confirmed amplified spontaneous emission from the system through spectral line narrowing and superlinear dependence of light emission on pump intensity. Lasing and its wavelength tuning for the film were succeeded with a relatively compact optics of 10 cm dimension which is manipulatable by one mechanical knob. For further improvement, development of optimized materials is very important issue. We have synthesized an azocarbazole molecule with a cationic alkyl chain being able to couple to anionic sites of DNA. The results on photoinduced birefringence of the material will be described at the conference.
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