Sub-external cavity effect and elimination method in laser self-mixing interference wave plate measurement system

• 来源期刊: 中国物理B（英文版）
• 关键词: self-mixing interference non-coated wave plate measurement self-consistent model
• 年，卷（期）: 2018,（2）
• 页码范围: 349-354
• 页数: 6页
• 语种: 英文
• DOI: 10.1088/1674-1056/27/2/024201

摘要

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-external and an external cavity is established,and the sub-external 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-external cavity effect.Experiments are carried out on the synchronously tuning double external 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.