| abstract |
A polarization imaging apparatus measures the Stokes image of a sample. The apparatus consists of an optical lens set 11 , a linear polarizer 14 with its optical axis 18 , a first variable phase retarder 12 with its optical axis 16 aligned 22.5° to axis 18 , a second variable phase retarder 13 with its optical axis 17 aligned 45° to axis 18 , a imaging sensor 15 for sensing the intensity images of the sample, a controller 101 and a computer 102 . Two variable phase retarders 12 and 13 were controlled independently by a computer 102 through a controller unit 101 which generates a sequential of voltages to control the phase retardations of VPRs 12 and 13 . A set of four intensity images, I 0 , I 1 , I 2 and I 3 of the sample were captured by imaging sensor 15 when the phase retardations of VPRs 12 and 13 were set at (0,0), (π,0), (π,π) and (π/2,π), respectively Then four Stokes components of a Stokes image, S 0 , S 1 , S 2 and S 3 were calculated using the four intensity images. |