Computer simulations on near-field scanning optical microscopy: Can subwavelength resolution be obtained using uncoated optical fiber probes?

Recent experiments claim that subwavelength resolution can be obtained with an optical scanning microscope using uncoated optical fiber probes. In these experiments, linearly polarized light is sent down the fiber which is reflected and depolarized in the tip-sample region. The internally reflected signal in the orthogonal polarization is detected. Here, numerical solutions of the vector Maxwell equations for a model are discussed. In this model, subwavelength resolution can indeed be obtained in the above mode, while this is not possible without polarization sensitivity. The influence of parameters such as polarization, different scanning modes and tip-sample distance is discussed.