基于三稳频激光波长的相移干涉测量法修正空气折射率湿度参数

针对公式法测量空气折射率受到Cd光源频率稳定性低和应用温度区间小的影响，其湿度修正误差不适应当前光学精密测量的实际需求的问题，提出了基于相移干涉光路的折射率测量光路.该光路由一个相移干涉光路和一个辅助角度测量干涉光路组成，并采用3个高精度稳频波长作为光源（532，633，780 nm）.在14.6~24.0℃温度区间内进行实验，获得了对湿度的修正系数并得到修正公式.将其用于实验比对，表明所得公式的测量精度优于Boensch公式. 

Humidity Correction of Air Refractive Index Based on a Phase Shift Interferometry with Three Stabilized Laser Wavelengths

Revised Edlen's equations by G.Boensch and E.Potulski are mostly used to calculate air refractive index at present.Since the correction of the humidity in the equations is performed in a narrow temperature range around 20℃ and the light frequency of the four wavelengths 114Cd lamp are not stabile,their applications have been limited in present optical precision measurement.To solve these problems,a refractive index measurement system was presented based on phase step interferometry.First,the configuration and principle of the optical system were introduced,which consisted of a phase step interferometer with three stabilized laser sources and an assistant angle sensitive interference optical path.Then the experimental and computing processes were induced.Finally,the experiments were carried out at different temperature.The corrected coefficients of the humidity on air refractive index were measured and corresponding revised equation was acquired.The comparison results indicate that the correction accuracy with the presented equation is better than that by G.Boensch.Moreover,the applicable temperature range extends to 14.6～24.0 ℃.