ABSTRACT
We demonstrate an efficient approach for the investigation of polarization states of a Bessel beam along the propagation direction. Furthermore, we propose a method to generate Bessel-moiré using a birefringent lens and Wollaston prism. The analysis showed that an experimentally generated incoherent moiré pattern is analogous to a theoretically simulated pattern. Moreover, we verified that inhomogeneous polarization states of a Bessel beam are still present in Bessel-moiré along its propagation direction. Our observation of Bessel-moiré due to mechanical vibration depicts the fact that incoherent moiré is stable, whereas the coherent moiré is sensitive to external vibration only along its propagation direction.
ABSTRACT
A novel surface plasmon resonance (SPR)-mediated Moiré fringe generation is theoretically and experimentally investigated using a birefringent lens (BL) and a Wollaston prism. Birefringent lens having two longitudinally shifted focal points provides radial shear, whereas Wollaston prism introduces lateral shear between the two radially sheared patterns for mutual orthogonal polarizations. Thus Moiré-like pattern is produced at the overlapping region of those patterns. Brief theory and experimental demonstration of coherent and incoherent Moiré fringe generation by such dual shearing is presented. The appearance and disappearance of Moiré pattern with the rotation of the analyzer axis has also been demonstrated. A modified experimental setup has also been developed to observe the influence of plasmonic excitation on such patterns which can be further utilized for photonic applications such as sensing and imaging.
