Electrically Tunable Flexible Circularly Polarized Laser with Ultrahigh Asymmetry Factor

TL;DR

Researchers developed a flexible laser that emits circularly polarized light with high efficiency and can be tuned electrically.

Contribution

The work introduces a flexible, electrically tunable circularly polarized laser with an ultrahigh asymmetry factor.

Findings

Flexible CP lasers with multicolor emission (blue, green, red) were demonstrated using dye-doped CLC microdroplets.

An ultrahigh asymmetry factor (g_lum = 1.72) was achieved through chiral coating integration.

Electrically and mechanically tunable emission with reversible on/off switching was realized.

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.

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