Wollaston Prisms separate the unpolarized light into two orthogonally polarized outputs with an angle of separation based on the prism material, typically from 1 to 20 degrees. Currently, two materials in use are Quartz and calcite. Typically, the extinction ratio is more than 10000:1. The crystal quartz and calcite are capable on the wavelength range of 660nm to 1550nm and theoretically from 400nm to 2000nm and 350nm to 2300nm, respectively.
![](https://optics.scimertech.com/wp-content/uploads/2023/02/Untitled.png)
![](https://optics.scimertech.com/wp-content/uploads/2023/02/IMG-2969-300x300.jpg)
Calcite polarizers are birefringent calcite crystals. Due to the birefringent nature of calcite, waves polarized in the direction of the optical axis propagate with a different index of refraction than waves polarized orthogonally to the optical axis. The birefringence separates the two orthogonal polarization states of an incident beam. A calcite polarizer can be designed as either a polarization splitter/combiner or as a polarizer element that removes the angled, orthogonally polarized component of a beam. Our calcite polarizers are typically built out of two prisms, as shown in the drawing to the right. Since calcite is a soft crystal that is easily damaged, almost all calcite polarizers can be offered in metal housings. With convenient threading and adapters.
Test Note: The crystals were tested at two different wavelength with circularly polarized light and at one wavelength with a polarized light.
Crystal Substrate |
Quartz |
Calcite |
Extinction Ratio |
>10000:1 |
>10000:1 |
Beam Separation angle (Real time) |
1.001º@660nm, 1.002º@1500nm |
20.016º@660nm, 19.472º@1500nm |
Coating |
Uncoated |
Uncoated |
When tested both the crystals at polarized single mode 1330nm the intensity ratio of the orthogonal pairs were 10000:1