“…Self-mixing interference (SMI) is attractive for optical measurements in many fields, such as structural analysis [1], micro-damping vibration [2], [3], [4], motor runout [5], [6], [7], and medical diagnosis [8], [9], [10], [11], due to its inherent simplicity, compactness, and self-alignment [12]. Microscale vibration information can be easily obtained by using the SMI effect.…”