Dispersive effects in imaging polarimetry based on a wire-grid polarizer

Area of Science:

• Optics and Photonics
• Polarimetry
• Optical Engineering

Background:

• Wire-grid polarizers (WGPs) are crucial components in imaging polarimetry.
• The dispersive characteristics of WGPs can impact system performance, especially under off-axis conditions.
• Understanding these effects is vital for accurate polarized light imaging.

Purpose of the Study:

• To investigate the impact of light dispersion from WGPs on imaging polarimetry.
• To quantify the non-uniformity and image misregistration caused by WGP dispersion.
• To highlight the necessity of managing WGP dispersion in polarimeter design.

Main Methods:

• Analysis of light dispersion effects in WGPs.
• Evaluation of WGP performance metrics like transmittance and extinction ratio under dispersion.
• Simulation or measurement of lateral spread and spectral image misregistration.

Main Results:

• WGP dispersion leads to significant non-uniformity in contrast, exceeding 0.84 for transmittance and 0.90 for extinction ratio.
• Dispersion causes lateral spread in the imaging plane, inducing spectral image misregistration.
• Misregistration can be several pixels without higher-order modes and severe with them.

Conclusions:

• Dispersive effects of WGPs are critical in imaging polarimetry, causing non-uniformity and misregistration.
• Accurate polarized scene extraction requires careful design of imaging polarimeters to mitigate WGP dispersion.
• Future polarimeter designs must incorporate strategies to manage these dispersive phenomena.