Low‐Voltage Operating Multi‐Color Tunable Chiral Liquid Crystal Laser with Continuous and Broadband Emission From a Single Pixel

ABSTRACT The development of full‐visible tunable lasers is critical for emerging photonic applications, including displays, spectroscopy, and quantum technologies. Despite their potential, conventional tunable lasers are limited by narrow spectral ranges, complex fabrication process or bulky architecture. Chiral liquid crystal (CLC) lasers provide a promising alternative due to their self‐assembled photonic bandgap structures and responsiveness to external stimuli. However, challenges remain in simultaneously achieving low‐voltage electrical tunability and overcoming the limitations in the tunable spectral range imposed by narrow dye emission bandwidths. Moreover, for practical operation, dynamic tuning with homogeneous CLC systems is highly desirable. In this study, we report a multi‐color, electrothermally tunable CLC laser system that addresses both issues. Utilizing low‐voltage resistive heating (<1.5 V), we demonstrate continuous wavelength tuning of photonic bandgap. Furthermore, by modulating the Förster resonance energy transfer between heterogeneous dyes, we achieve broadband optical gain, enabling continuously tunable lasing in the visible range from 492 to 629 nm (137 nm tuning) within a single homogeneous device. Finally, as a novel demonstration in tunable lasers, we present a 2 × 2 (Tetra) single‐pixel multi‐color array that achieves reconfigurable red, green, and cyan lasing within each pixel, thereby offering a compact and subpixel‐free architecture for next‐generation full‐color laser displays.