DETERMINATION OF GEOMETRIC PARAMETERS OF GRADIENT STRUCTURES FORMED IN OPTICAL GLASS BY THE ELECTRON BEAM METHOD
The results of experimental studies of the geometry of gradient structures formed in optical glass by the method of electron-beam modification of its surface are presented. The expediency of using the atomic force microscopy method for determining the geometrical parameters of microlayers formed in the surfaces of optical materials by the method of their electron-beam modification is substantiated. A new method for determining the basic geometric parameters (thickness of the gradient layer, topology of the interface “gradient layer – the basis of the material”, surface microrelief, etc.) gradient structures, based on the method of atomic force microscopy is proposed. The proposed method is based on the principle of the complex application of various operating modes of an atomic-force microscope (the results of the instrument operation are considered, both in contact and in non-contact modes) in one measurement cycle. According to the proposed method, the dependencies between the change in the refractive index and the modes of electron-beam modification of the optical glass surface, as well as the dependence between the electron-beam effect modes and the geometric parameters of the gradient structure on the glass (thickness of the gradient structure, surface microrelief and interface between the layers and the base material ). The possibility of predicting the development of hidden microdefects at the interface “gradient layer – the basis of the material” is shown. Proved high reliability and adequacy of the proposed method by comparing the results obtained with the results of determining the geometric parameters obtained by other alternative methods.