Fig. 6: Scheme of the operation of the narrow polarization gate.
From: Complete spatiotemporal and polarization characterization of ultrafast vector beams
Firstly, a multiple-order quarter-waveplate (QWM) and, secondly, a zero-order quarter-waveplate (QW0) are oriented with their fast axes at 0° and 45°, respectively. When the input pulse has linear polarization (LP) at 45° (upper drawing), the narrow gate operates normally and produces a pulse with circular polarization (CP) at the edges and LP at the centre. If the input pulse has LP at 0° (lower drawing), the output pulse presents constant CP. The ellipticity \(\varepsilon\) is represented in the given colour scale.
