Surface microtopography measurement of a standard flat surface by multiple-beam interference fringes at reflection

摘要: This paper describes a multiple-beam interferometry technique at reflection for measuring the microtopography of an optical flat nominally of λ/20. The measured value is the result of a piezoelectric phase shifting that made it possible to cover the area between the orders. The exposure area of the tested optical flat covered by the collimated laser beam is about 2cm. The images captured by the digital detector were corrected using dark/flat field method. The uncertainty in the measurement due to incomplete parallelism of the incident beam and …