基于光学外差干涉的折射率测量方法

A refractive index measurement method based on optical heterodyne interferometry

基于光学折射率是材料的一个重要的物理参数,提出了一种在泰曼格林干涉系统基础上的光学外差干涉折射率测量方法及系统。测量系统将样品放置在系统外,采用双光束干涉探测,使系统更加稳定、调整简单、测量更加精准。实验上测量了K9玻璃块样品在超连续激光光源中心波长790nm、带宽20nm下的折射率,验证了方法的有效性和可靠性。实验结果表明,系统能够准确测量出样品的折射率,测量稳定性较高,精度可以达到10-4;适用于可见光和近红外波段透明物质的折射率测量,应用领域广泛。

The optical refractive index of a kind of material is an important physical parameter. A measurement method of the refractive index based on optical heterodyne interferometry using Twyman-Green interference system is proposed. The sample is placed outside the measurement system and detected by the double beam interferometry,which makes the system more stable,more accurate and easy to adjust. The refractive index of K9 glass block samples is measured experimentally by supercontinuum laser with 790 nm center wavelength and 20 nm bandwidth,in the process of which the validity and reliability of this method was verified. The experiment results indicate that this system is able to measure refractive indices with high stability and precision of10-4. The system can be applicable to all refractive index measurement of transparent materials in the wavelength ranging from vision light to near infrared light.