Direct generation of optical diffractive elements in perfluorocyclobutane (PFCB) polymers by soft lithography

Optically diffractive line gratings with 0.58-μm feature sizes have been generated in 100-μm perfluorocyclobutane (PFCB) polymer films by direct micromolding using only a silicon master. Strong reflectivities from the green to red portions of the visible spectrum, depending on incident beam angle, were observed with 3 dB bandwidths of approximately 30 nm. This "negative mold-free" technique permits, for the first time to our knowledge, feature reproduction at submicrometer size scales, eliminates several steps from conventional soft lithographic methods, and marks itself as a practical means for rapidly generating planar photonic structures that operate spectrally in the visible and the near IR telecommunication bands.