Developing flexible liquid crystal defect mode lasers

The challenges associated with developing a flexible defect-mode liquid crystal (LC) laser are addressed in this paper. To begin with, we discuss the process for creating a well-aligned photopolymerized film of chiral nematic LC using various surface alignment layers such as polyvinyl alcohol, sulphonic azo-dye and rubbed polyimide. A single mode flexible defect-mode laser is demonstrated with an excitation threshold fluence of 60μJ/cm2/pulse. In accordance with previous studies, results from simulations based on the 4×4 Berreman model show that the wavelength and the number of laser modes are determined by the thickness of the defect layer. The proposed flexible laser can be used to form lasers that can be integrated into conformable platforms and that can be used to control the beam direction without the need for additional optical components.