Achromatic phase shifting by a rotating polarizer

Achromatic-phase-shifting low-coherence digital holography: theoretical analyses of zero-phase-shifting error condition and linear and nonlinear calibrations

“…The HWP and QWP were designed for 780 nm and the other parameters of the RP-APS had the same values as those used in Refs. [14,15]. The phase errors at z = 0.0 and 27.6 lm were *2p 9 0.975 9 10 -5 radian and *2p 9 0.986 9 10 -5 radian, and the difference was *2p 9 1.1 9 10 -7 radian.…”

“…This was expected, as the noise was derived from the phase-shifting errors for broadband light; however, no detailed analysis has been carried out yet. In order to decrease the error, a polarization interferometer with an achromatic-phase shifter (APS) [14] has been applied to full-field coherence tomography for biological imaging [15]. The PS-LCDH with the APS also has the potential for biological imaging with high repetition, but a performance analysis has not been carried out.…”

“…A sinusoidal error generated in recording a hologram by PS-LCDH was drastically decreased by introducing an APS implemented with a rotating polarizer (RP), called an RP-APS [14,15]. The small residual error arose from imperfections in the RP-APS, and it was eliminated by the use of an ideal APS (I-APS).…”

“…[14,15], the RP-APS is implemented with two half-wave plates (HWPs), a quarter-wave plate (QWP), and a rotating polarizer (RP). Horizontal and vertical linearly polarized beams are, respectively, converted to right and left circularly polarized beams after passing through the combination of wave plates.…”

White-light ellipsometer with geometric phase shifter

“…The second method is based on Pancharatnam's phase, which is a geometric or topological phase associated with a change in the polarization state [16][17][18][19][20]. A polarization state which describes a closed loop on the Poincaré sphere acquires a geometric phase equal to half the solid angle subtended at the center of the Poincaré sphere by the loop.…”