Surface Relief Formation in Azobenzene-Containing Polymers Using 325 nm Holography

Abstract

Surface relief (SR) formation in polymethacrylate films with azobenzene side groups was investigated via a holographic method using 325 nm He–Cd laser, which generated stable cis isomers. Because the azobenzene molecules underwent both photoinduced reorientation and photoisomerization according to the polarization and intensity distribution of the interference beams, formation of the SR structure depended on both the exposure energy and polarization distribution. For intensity holography, both the photogenerated cis isomer distribution and polarization direction of the exposed beams played important roles in SR formation, which accompanied the molecularly reoriented SR structure. For polarization holography, a small SR structure accompanied the periodical molecular orientation in the initial stage of polarization holography due to uniform distribution of cis isomer. However, a SR structure larger than that generated by intensity holography was produced in the photostationary state.