Investigation of the Angle-detecting Mechanism of GaN-based Optical Devices Incorporating Liquid Pendulums

In this letter, we report GaN-based optic device containing the InGaN/GaN multiquantum wells is able to emit and detect light. The angle-detecting mechanism is predicted by ray-trace simulations and verified by experimental measurements. The dynamic responses of the device to tilt angle are investigated by comparing three different liquids as liquid pendulums. The measured results indicate that the device exhibits superior immunity to magnetic interference compared with a commercial MEMS-based angle sensor. The attractive features of the proposed device, such as high compactness, small size, low cost, large linear measuring range, and resistance to magnetic interference, open up new possibilities for extending the wide applications of angle detection based on GaN optical devices.