シヤリング干渉計による顕微鏡対物レンズのレスポンス函数の測定

抄録

A shearing interferometer by the use of polarized light is devised for the measurement of generalized transfer functions of microscope objective, the object plane of which is illuminated through a condenser. The relative shear between two interfering wave-fronts is obtained by a birefringent system, which is located at the focus of a converging wave-front and is made movable normally to the optic axis.
The birefringent system consists of a piano-convex lens and a piano-concave one of calcite cut parallel to the optic axis and cemented together with their axis crossing at right angle. This system can easily be applied to the autocollimation method and is capable of obtaining a sufficient amount of light without reducing the visibility of interference fringes over the whole range of shear.
These are the conditions indispensable for measuring the transfer function of microscope objectives which have a small amount of residual aberrations and therefore have a tolerable value of response for all the spatial frequencies corresponding to the entire range of shear. Experiments were carried out on low power microscope objectives with primary spherical aberrations of 0.0, 0.5 and 1.0λ. Experimental results show fairly good agreement with calculated