Hexagonal Benz-shaped GaN Microcavity Lasing and its Sensing Characteristics

Abstract Pressure sensing has broad applications across various fields such as health monitoring, industrial manufacturing, medical equipment, and materials analysis. In recent years, research on active optical mechanical pressure sensing with high-density optoelectronic integration advantages has become a significant research focus. However, current active optomechanical sensing devices, the measured spectrum represents an averaged result over a region with a stress gradient, which inherently lacks the precision to accurately reflect the spectral response at a specific localized point. As a sensor, it reduces both the sensitivity and signal-to-noise ratio of optomechanical stress sensing. To address this issue, we designed and fabricated a device with suspended GaN hexagonal Benz-shaped optomechanical microcavities and investigated its stress sensing characteristics. Through spectroscopy and photoluminescence lifetime testing, it was found that the stress at each point on the side of the hexagonal Benz-shaped device is different, and the stress magnitude is inversely proportional to the deformation. Under increasing of stress, the Quantum Confined Stark effect leads to a redshift in the fluorescence spectrum peak. Furthermore, by monitoring the beat frequency of lasing peaks at different locations under increasing pump power, it is demonstrated that this approach enhances both sensitivity and stability for optomechanical stress sensors. The findings of this study provide significant insights and valuable references for improving the sensitivity of active optomechanical stress sensors and optimizing their structural design.