Abstract

Polymers with disperse red 19 (DR19) pendant groups showed a large photoinduced birefringence when exposed to linearly polarized ultraviolet or short wavelength visible light because of trans–cis isomerization of DR19 groups. High resolution birefringent micropatterning (>2000 lines/mm) has been demonstrated by using this entirely dry processing technique. We have defined binary wave-plate arrays of 5 × 5 μm pixel size with different optical axes and phase delays in alternating pixels by using a commercial mask aligner. This photo exposure method is simple and versatile. The optical axis of the wave plate is defined in the direction of the exposure polarization so that wave plates with different orientations can be defined in the same film by proper masking and control of exposure polarization. The phase delay is controlled by the exposure fluence; therefore, different retardations can be obtained from different exposure doses. These multi-orientation birefringent arrays can find applications in areas of binary diffractive optics, optical information processing, storage, and display. Some examples are shown experimentally. Birefringent optical waveguides have also been defined by this technique. Their properties and potential device applications will be discussed.

© 1992 Optical Society of America