Possibilities to improve measuring precision of the dispersion energy with an adhered cantilever ^(a)

Abstract Measurement of the Casimir forces at distances smaller than 50 nm is a complicated problem. The method of adhered cantilever does not suffer from loss of stability at short distances and was used recently to measure the adhesion energy due to the dispersion forces with a precision of 10%. In this paper the most important source of errors related to inhomogeneity of the thickness of the cantilevers is discussed. Analytical expressions for the shape of an inhomogeneous cantilever and the adhesion energy are derived. It is demonstrated that monitoring of the cantilever thickness along its length allows five times improvement of the precision. A small twisting of the cantilevers is indicated as an additional source of important errors. This parameter controls the precision of equilibrium average distance between the surfaces and the true adhesion energy between parallel plates.