Electrically Tunable Flexible Circularly Polarized Laser with Ultrahigh Asymmetry Factor

Abstract

Circularly polarized (CP) laser emission delivers considerable promise for future photonic applications of chiral light sources and investigation of chiral light–matter interactions. However, the low asymmetry factor (g_lum) and lack of effective tuning have significantly hindered the development of such chiral light sources. Herein, multicolor (blue, green, and red) flexible CP lasers are demonstrated based on dye-doped cholesteric liquid crystal (CLC) microdroplets embedded in a polydimethylsiloxane (PDMS) elastomer. The CLC microdroplets, characterized by their left- or right-handed helical superstructures, serve as chiral cavities, facilitating the realization of CP lasing. By integrating chiral coating, CP lasing with opposite handedness is further effectively separated, notably enhancing the circular polarization degree and enabling an ultrahigh asymmetry factor (g_lum = 1.72). Importantly, these flexible CP lasers exhibit both electrically and mechanically tunable emission, demonstrating excellent wavelength tunability. In addition, the applied electric field allows dynamic control over the laser emission intensity, enabling fully reversible on/off switching. This work represents an important step forward to the development of high-performance chiral light sources with facile tunability and offers valuable insights for future chiroptical device design.