Thermally tunable liquid crystal distributed feedback laser based on a polymer grating with nanogrooves fabricated by nanoimprint lithography

This work demonstrates a thermally tunable dye-doped liquid crystal (DDLC) distributed feedback (DFB) laser based on a polymer grating. The surface emitting DDLC DFB laser is supported by the second-order Bragg grating with nanogrooves of periodicity of 360 nm which is pre-fabricated using the UV nanoimprint lithography (UV-NIL) method. The lasing wavelength of the DFB laser can be tuned from 625.1 nm to 606.35 nm if the temperature increases from 10 °C to 50 °C. The tunability of the laser is attributable to the temperature-sensitive feature in the effective refractive index of the LCs. Such a tunable laser can be used in the fabrication of tunable optical sources and biosensors, and in integrated photonic circuits, optical communication, and laser displays.