Whispering-gallery mode lasing from patterned molecular single-crystalline microcavity array

Organic single-crystalline materials have attracted great attention for laser applications. However, the fabrication of laser resonators and pattern of crystals are still intractable problems. Organic single crystals have been limited to fundamental property studies despite their superior photonic characteristics. In this work, whispering-gallery mode (WGM) resonators of BP1T and BP2T crystalline materials have been fabricated through a combination method with improved lithography and dry etching. Crystalline microresonators with different geometries over a large area are top-down fabricated with submicrometer spatial resolution. WGM lasing oscillation from circular, hexagonal, pentagonal and square resonators is definitively observed. The BP1T and BP2T crystals are characterized with high refractive index, and stable lasing in aqueous solution is demonstrated besides in the air environment. It is expected that organic crystalline materials would be used for the practical applications in a variety of organic electronic and optical devices.