Self-assembled organic microcrystal microcavity lasers (Conference Presentation)

Abstract

Organic solid-state lasers (OSSLs) have been widely investigated during the past decades, owing to their amenability to low-cost and low-temperature processing, compatibility with plastic substrates, and broad spectral tunability. A variety of optical resonators have been applied for optically pumped OSSLs, including planar waveguide Fabry-Perot (FP) microcavity, distributed feedback (DFB), whispering-gallery mode (WGM) microring microresonator, and photonic band-gap structures. Nevertheless, electrically driven OSSLs remain still a great challenge, partially because the conflicting requirement between large stimulated emission and high charge carrier mobility narrows the range of organic semiconductor gain materials available for electrically driven OSSLs. Recently, we demonstrated that organic microcrystal with well-defined dimensions and different polymorphisms can serve as microresonators for fundamental investigation of optical confinement effect on laser behaviors, such as nanowire FP and microdisk WGM microlasers. Moreover, organic single crystals are ideal for use as high-mobility materials, because their long-range ordered structures minimize traps and are free from grain boundaries. Therefore, organic microcrystals provide a platform to combine high carrier transport, efficient optical gain, and microresonator together on the way to develop electrically pumped organic lasers. In this talk, I will present our research on the photonic performance of molecular microcrystal microcavities and the latest breakthroughs toward organic microlaser devices. Overall, organic microcrystals bring tunable optical properties based on molecular design, size-dependent light confinement in low-dimensional structures, and various device geometries for nanophotonic integration.