: Minsu Kang, Changhyun Han and Heonsu Jeon

: Optica 7(12), 1788-1795 (2020)

Maskless photolithography based on the digital micromirror device (DMD), a two-dimensional micromirror array, is considered the next-generation low-cost lithographic technology. However, the DMD-based digital photolithography has been implemented only for micrometre-scale pattern generation, whereas sophisticated photonic devices require the feature sizes of approximately 100 nm. In this study, a high-magnification objective lens (200×) is adopted for a custom-built digital photolithography system to generate submicron- scale patterns. Techniques augmenting the digital photolithography, pattern tilting and greyscale exposure, are also improvised. Photonic crystal band-edge lasers of various lattice structures and periods are demonstrated as quality-assessment testbeds.