CIAO's polarimetry has a rotatable and achromatic half wave plate and a wire grid analyzer for measurement of linear polarization at JHK band. Circular polarimetry with a quarter wave plate is also available in a shared-risk mode from S06A. You can download a paper about CIAO polarimetry.
Characteristics of polarization components
Calculation of SNThe signal-to-noise ratio (SNRs) per an image with a polarization position angle is calculated by
SNR = sqrt(2) / pacc.
Where pacc is required accuracy of degree of polarization. Generally, Pacc should be 3 times or better than predicted degree of polarization. As an example, we consider 10% of degree of polarization is predicted in our object, the accuracy pacc requires <3.3%. The SN to be required is >43.