Calculation Method for the Geometric Dimensions of a Scanning Near-Field Optical Microscope Optical Fiber Probe and Experimental Verification

This study proposes an innovative calculation method for the geometric dimensions of a scanning near-field optical microscope (SNOM) optical fiber probe. We employ molecular mechanics and vibration theory to construct a simulative measuring model of a SNOM. We use a complex Boolean operation to arrange the probe and the sample atom-by-atom and then establish an atomic model for the simulative measuring model of SNOM. We conduct a scanning electron microscopy (SEM) photographing experiment to measure the geometric dimensions of the probe and then draw a relational diagram of the geometric dimensions and deduce their relational equations. We also find the potential energy parameter values of the Morse potential energy model among different atoms in order to solve the problem of the unknown potential energy parameter value by using the Lorenz- Berthelot mixing rule. We combine the optimal search of the Levenberg-Marquardt method with a reasonable convergence criterion to acquire the optimal geometric dimensions. In addition, a SNOM optical fiber probe is used to compare the results of the experimental and simulative measurements.