Development of laser interferometer with picometer resolution using frequency tunable laser-The 5th report: Compensation of the displacement measurement due to the fluctuation of the air refractive index

摘要

The fluctuation of the air refractive index (n_(air)) in the applications of laser interferometer is a dominant uncertainty source of the displacement measurement. In the report, we have been developing a displacement measuring system by using the phase modulation homodyne interferometer (PMHI) and an external cavity laser diode (ECLD), in which the fluctuation of nair is measured and the measurement uncertainty generated by this refractive index fluctuation is compensated.