Laser mode control based on chiral liquid crystal microcavities

Abstract

Chiral liquid crystal (CLC) microcavity lasers have gotten a lot of interest because of their very sensitive response to external stimuli and ability to produce both whispering gallery mode (WGM) lasing and photonic band gap (PBG) lasing. In this work, we report a CLC microcavity laser based on Förster resonance energy transfer (FRET). By introducing FRET, energy transfer of a WGM laser is achieved. And PBG laser emission with a tuning range of 584–696 nm is achieved by temperature modulation. By changing the pump position, a lasing mode switch between FRET of the WGM laser and FRET of the PBG laser can be achieved. The application of energy transfer in CLC microcavities has expanded the spectral range of PBG lasers. The WGM laser generated by energy transfer demonstrated a sensitivity of 2.17 nm °C⁻¹ in a CLC microdroplet with a diameter of 22 μm. This work extends the application of CLC microcavities in the field of optical devices and sensing technologies.