Super‐Wide Temperature Lasers Spanning from −180 to 240 °C Based on Fully‐Polymerized Blue Phase Superstructures

Abstract Blue phase liquid crystal (BPLC) lasers have potential applications in displays, sensors, and anti‐counterfeiting fields owing to their outstanding optical properties. However, there remain challenges on lasing below 0 °C, which significantly limits the potential application of BPLC lasers in low‐temperature environments. In this work, BPLC lasing below 0 °C is realized for the first time in a super‐wide temperature range of −180–240 °C using a well‐designed fully‐polymerized BPLC system with a narrow line width of 0.0881 nm and a low lasing threshold of 37 nJ pulse −1 . This fully‐polymerized BPLC both effectively avoids low‐temperature random crystallization and has excellent compatibility with dye molecules that significantly widen the lasing temperature range below 0 °C. Besides, the variations of laser peak and threshold are also revealed below 0 °C, that is, redshifted laser wavelength and increased threshold value with decreasing temperature, which contribute to a blue‐shifted laser signal and a U‐shaped lasing threshold in −180–240 °C. These unique laser behaviors can be ascribed to the temperature‐dependent anisotropically microstructural deformation of the BP lattice. This work not only opens a door to the development of low‐temperature BPLC lasers but also sets out important insights in the design of novel organic optical devices.