,Sub-external cavity effect and elimination method in laser self-mixing interference wave plate meas

• 作 者: Haisha Niu Yanxiong Niu Jianjun Song
• 机 构: School of Instrument Science and Optoelectronic Engineering, Beihang University, Beijing 100191, Chi
• 出 处: 中国物理B（英文版）
• 发表日期: 2018年2期
• 关键词: self-mixing interference non-coated wave plate measurement self-consistent model

Laser self-mixing interference (SMI) wave plate measurement method is a burgeoning technique for its simplicity and efficiency.But for the non-coated sample,the reflected light from the surface can seriously affect the measurement results.To analyze the reason theoretically,a self-consistent model for laser operation with a sub-exteal and an exteal cavity is established,and the sub-exteal cavity formed by the sample and a cavity mirror is proved to be the main error source.A synchronous tuning method is proposed to eliminate the sub-exteal cavity effect.Experiments are carried out on the synchronously tuning double exteal cavities self-mixing interference system,and the error of the system is in the range of-0.435° ～ 0.387° compared with the ellipsometer.The research plays an important role in improving the performance and enlarging the application range of the laser self-mixing interference system.