Application of frequency combs in the measurement of the refractive index of air

摘要: We report a new method in the precision measurement of refractive index air using highly unbalanced Michelson interferometer with femtosecond optical frequency comb as light source. Standard dry is filled into 30m multipass cell, serving long arm interferometer, while short acts reference path. Both time and domain interferograms are recorded to measure air. The deviation our experimental results Edlen’s formula 1.4×10−9 at 800nm. Our experiment has standard error 5.2×10−9 fixed parameters (pressure temperature). This achieved by putting cell temperature-stabilized box, also locking path length He–Ne laser. temperature stabilization 0.8mK for 25h. corresponds 0.4μm change. enables us achieve 7nm path-length change outside cell. Combined ac...