Temperature-Tunable Heliconical and Ferroelectric Nematics for White Lasing.

Nematic Liquid Crystals (LCs), noted for their simple molecular alignment and broad use in optoelectronics, remain unmodified for over a century. However, in 2017, a unique polar phase, the ferroelectric nematic (NF), is confirmed. Subsequently, in 2024, the revolutionary spontaneous mirror symmetry breaking of ferroelectric twist-bend nematic chiral structures (NTBF phase) is demonstrated. Nematic LCs are commonly used as optically active matrices for luminescent dyes, allowing the fine-tuning of emission properties through external fields. In this manuscript, the pioneering temperature-tunable lasing studies utilizing commercial dyes doped into a mixture that displays the NTBF phase within an exceptionally low-temperature range of 34-43.3 °C are shown. The subsequent experiments explore how lasing characteristics within NTBF and NF phases can be employed in a single, compact device to produce multicolor and white lasers. Furthermore, there are introduced spontaneously formed emissive fibers from the NTBF phase. As perspectives, the voltage-dependent increase of lasing intensity in NF is demonstrated, showing the exceptional result in two differently arranged LC cells. The findings highlight that simple molecules, like those in nature and living organisms, can shape intricate systems with significant implications for the accelerated progress of laser and display technologies, along with Li-Fi concepts.