High-quality micropattern printing by interlacing-pattern holographic femtosecond pulses

Abstract

To improve the efficiency of femtosecond laser direct writing, holographic femtosecond laser patterning using spatial light modulators has been widely used for the processing of micro/nanopatterns. However, the speckle noise of modulated optical fields severely limits the quality of fabricated patterns. We present a simple and effective method which involves interlacing a target pattern into a series of target subpatterns that consist of spaced spots to solve this problem. The separation of spots weakens the random interference between adjacent spots of optical fields, so the speckle noise reduces effectively, which improves the uniformity of the modulated optical fields and makes the fabricated patterns with high quality. With optimal interlacing numbers, complex micropattern arrays containing curved edges and sophisticated structures can be fabricated with superior quality and high efficiency. Binary holograms with improved optical characterization are realized by using the interlacing-pattern method, revealing the extensive potential of this method in micropattern processing and functional device fabrication with high quality and efficiency.