Glan Thompson Polarizers

Glan Thompson Polarizers

Glan Thompson polarizer is  made of two calcite prisms or a-BBO prisms cemented together. Two types  of Glan Thompsons are available. One is the standard form and the other  is the long form. Their length to aperture ratios are 2.5 : 1 and 3.0 : 1  respectively. Glan Thompsons tend to have higher extinction ratio than  air spaced polarizers. In the ultra violet spectrum, their transmission  is limited by absorption in birefringent materials as well as the cement  layer. a-BBO polarizers and Calcite polarizers can be used from about  220 to 900nm and 350 to 2300 nm respectively.

The polarizers have the  widest field angle of any design. The standard form of this polarizer  with 2.5:1 length to aperture ratio has a full acceptance cone angle of  more than 15° @ 589nm, symmetric about the input axis, whilst the long  form with 3:1 ratio has a field angle >26° . The polarized field F1  and F2 of all these is shown in the plot below.

Angular Field vs Wavelength

Standard Products