Electrically switchable whispering gallery mode lasing from ferroelectric liquid crystal microdroplets

Abstract

Liquid crystal microdroplets have received considerable attention over recent years owing to their potential applications in chemical, biomedical sensing and lasing. We report experimental studies on whispering gallery mode lasing from dye-doped ferroelectric liquid crystal microdroplets suspended in a low refractive index and highly transparent perfluoropolymer at ambient temperature. We show that the lasing threshold pump energy of ferroelectric microdroplets is much lower than that of the nematic and cholesteric microdroplets. With the increasing electric field, the linewidth increases, while the lasing intensity decreases and eventually switches off beyond a particular field. Since the switching response time is fast (≈350 μs), ferroelectric liquid crystal based microlasers are useful for applications as electrically switchable sources in miniaturised devices and in soft photonic circuits.