White-light circular-polarization imaging using pairs of polarization gratings and wedge prisms

Abstract

A novel, to the best of our knowledge, method for circular-polarization imaging with white light is presented. The vital optical elements of the proposed system are two polarization gratings (PGs) and a wedge prism. The chromatic dispersion of the PG diffraction angle is compensated by the difference of the grating period for the two PGs. In addition, the distance between the diffracted lights on the imaging plane is controlled by using a wedge prism. As a result, S 3 of the Stokes parameter, including the wavelength dependence of a scarab beetle, was observed at a time, and the S 3 contribution to each color was determined by using the color filter of the light-receiving element. Because the white-light polarization image includes a lot of information about the illuminated structure, the proposed method should be applied to biomedical sensing and remote sensing.

Analysis of visualization through depolarization via light scattering related to surface structure in visible and infrared light

“…The PG has a function that it can selectively diffract the right-and left-handed circular polarizations (RCP and LCP) to +1st and −1st order directions because of the Pancharatnum-Berry phase. [22][23][24] To avoid an effect of diffraction angle dispersion of PG, a bandwidth of each LED is reduced by using BF. As the image sensor, a shortwave IR (SWIR) camera (CS-700IGA; Bitran Inc.), which has sensitivity for electro-magnetic wave at 400-1700 nm wavelength, was prepared.…”

Design and application of diffractive optical element: a review

“…The energy utilization rate of polarized DOE in the all visible light band was greater than 45%, and the extinction ratio was greater than 3.5 × 103, able to meet the needs of polarization imaging. To achieve polarization imaging of white light, Noda et al [60] proposed a white light circular polarization imaging technology based on dual polarization gratings and wedge prisms. Polarization gratings are used to image left-handed and righthanded circularly polarized incident light.…”

Polarization-probe polarization-imaging system in near-infrared regime using a polarization grating

“…Therefore, many potential applications of polarization imaging have been proposed, including biomedical sensing and remote sensing [1][2][3][4][5] . To measure these polarization images, various approaches have been proposed to date, including methods based on a rotating polarizer/compensator polarimeter, a micropolarizer/retarder array camera [6][7][8][9][10][11] , a channeled imaging polarimeter [12][13][14][15][16] , and an amplitude division camera [17][18][19][20][21] . Some polarization imaging methods are already being incorporated into commercial products.…”