surface plasmons are excited, the lateral shift of the reflected beam has been found to change from large negative values to large positive values as the thickness of the metal layer increases through a critical value. The maximal forward and backward lateral shifts can be as large as the half-width of the incident beam. As the width of the incident Gaussian beam decreases, we have found that the size of the lateral shift decreases rapidly, but the relative deformation of the reflected beam increases. In all cases studied, we have found that the reflected beam is split into two parts. Finally, we have found that the lateral shift of the transmitted beam is always positive and very weak. The lateral shift of the reflected beam studied here is large enough to be considered for application to optical devices.

This work has been supported by the National Research Foundation of Korea Grant (NRF-2018R1D1A1B07042629) funded by the Korean Government.

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