Rapid fabrication of large-area periodic structures containing well-defined defects by combining holography and mask techniques

We demonstrate a promising method to fabricate large-area periodic structures with desired defects by using the combination of multiple-exposure two-beam interference and mask-photolithography techniques. Multiple-exposure of two-beam interference pattern at 325 nm into a positive AZ-4620 (or a negative SU-8) photopolymerizable photoresist is used to form a square and hexagonal two-dimensional periodic structures. Desired defects are introduced in these structures by irradiating the sample with one beam of the same laser through a mask in which the design of defects is patterned. A 1cm x 1cm periodic structures with the lattice constant as small as 365nm embedding several kinds of defect, such as waveguide or Mach-Zehnder, was obtained by employing this combination technique. It shows that the proposed combination technique is useful for mass production of photonic crystal optoelectronics devices.