Numerical study of the process of optical radiation measuring using a hollow aperture cantilever

Background. Scanning near-field optical microscopy is a powerful and promising tool for studying the interaction of light with matter. Improving the quality and accuracy of measurements is a key challenge. When interpreting experimental results, it is important to consider the sensitivity of the cantilever to the polarization type. Aim. The aim of this study is to evaluate the sensitivity of a pyramidal aperture cantilever to the incidence angle of measured light. Methods. Using the frequency depended finite-difference time-domain method, it was shown that the incidence angle and the plane of incidence can affect the measurement process with an aperture cantilever for both proposed types of incident light polarization: linear and circular left-handed. Results. Simulation results show that with an increase in the incidence angle of measured light, the overall intensity inside the cantilever decreases by approximately 50 % and 30 % for linearly and circularly polarized light, respectively. Conclusion. This proves that the aluminum aperture cantilever is weakly sensitive to the longitudinal component.