Liquid crystal-based highly sensitive temperature sensor using the optical Vernier effect with monochromatic light

In recent years, the optical Vernier effect has shown great potential in sensing and metrology due to its enhanced sensitivity as compared to traditional interferometer-based sensors. However, the conventional setup to implement the optical Vernier effect requires specific arrangements such as a broadband light source, which is usually beyond the visible spectrum and a compatible spectrum analyzer with sub-nanometer resolution. This makes the setup costly. A simpler and cheaper alternative to implement the optical Vernier effect will make it more accessible and feasible for a wider range of applications. In this work, a highly sensitive temperature sensor based on the optical Vernier effect in a liquid crystal cell is proposed. The Vernier effect has been achieved using a CCD camera, a monochromatic light source, and a wedge-shaped liquid crystal cell. Experimentally, a sensitivity of 341.93 μm in the temperature range of to and a sensitivity of 1044.49 μm in the temperature range of to have been obtained. A theoretical analysis has been proposed to explain the working principle of the sensor, and a simulation has been performed to validate the experimental results. Further, a non-linear equation has been proposed to fit the shift versus temperature curve.