Researchers create a next-gen color-tunable laser by coupling an OLED device with chiral liquid crystals

Researchers from POSTECH (Pohang University of Science and Technology) have developed a next-generation laser platform that integrates OLED emissive materials with chiral liquid crystals (CLCs). The researchers show that this new laser offers precise color control under battery-level low voltage - basically a color-tunable emitting laser.

The researchers say that the helically ordered structure of CLCs forms a periodic resonant cavity capable of selectively amplifying specific wavelengths. The CLC was transformed it into laser-like emission by coupling it with a broadband-emission OLED device. The device offers ultra-narrow linewidth of approximately 1 nm (FWHM), achieving color purity tens of times higher than that of conventional OLEDs.

Beyond spectral narrowing, the team also achieved continuous wavelength tunability within a single device. By employing an electrothermal actuation mechanism, small electrical inputs induce controlled thermal modulation of the CLC helical pitch, thereby shifting the resonance wavelength. Notably, this enables continuous color tuning over a wide visible spectral range of approximately 135 nm under a low driving voltage below 1.5 V, overcoming the high-voltage limitations of conventional tunable laser systems.