CC-POL Components: Analyzer
Analyzer (Wollaston prism) splits incident light into the ordinary (o ray) and extraordinary (e ray) due to the slow and fast optical axis of the crystal
- Two beams are produced of orthogonally polarised light
- Angular separation of the two beams is proportional to the difference in the refractive index of the e and o rays (birefringence)
Both planes of polarised light are imaged, realising a factor of ~2 increase in throughput over single beam polarimeters and a further increase in accuracy due to elimination of atmospheric effects between exposures
Wollaston is typically placed in a collimated beam, as an angular divergence of the o and e rays is produced
Efficiency of polarisation is very high (~ᢛ%)
Possible drawbacks: reduced throughput, birefringence a l ? elongation of broad band images can occur, ghosting, lower EE