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
birefriengent materials as well as the cement layer. a-BBO
polarizers and Calcite polarizers can be used from about 220 to 900nm and
350 to 2300nm respectively.
This polarizer has 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, whereas 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 versus Wavelength:
Main Specifications
|
Material |
a-BBO,
Calcite |
Wavelength
Range |
a-BBO:
220-900 nm, Calcite: 350-2300 nm |
Extinction
Ratio |
Calcite:<5x10-5;
a-BBO:<5x10-6 |
Parallelism |
<1 arc Min |
Surface
Quality |
20-10 |
Beam
Deviation |
< 3 arc minutes |
Wavefront
Distortion |
l/4@633nm |
Damage
Threshold |
>200 MW/cm2 |
Coating |
Single MgF2 |
Mount |
Black Anodized Aluminum |
|
Standard Products:
1. a-BBO
Glan Thompson Polarizer(Special for DUV, Visible and NIR(200-1100nm)
|
Part No.
|
L/CA
|
Extinction Ratio
|
Angular Field(°)
|
C.A.
fa (mm)
|
O.D.
fd (mm)
|
L±0.1
(mm)
|
GMP-6006
|
1.6
|
<5x10-6
|
>15
|
6.0
|
15.0
|
18.0
|
GMP-6008
|
8.0
|
25.4
|
21.0
|
GMP-6010
|
10.0
|
25.4
|
24.5
|
GMP-6015
|
15.0
|
30.0
|
32.5
|
GMP-6020
|
20.0
|
38.0
|
40.7
|
|
2. Calcite Glan Thompson Polarizer
|
Part No.
|
L/CA
|
Extinction Ratio
|
Angular Field(°)
|
C.A.
fa (mm)
|
O.D.
fd (mm)
|
L±0.1
(mm)
|
GMP-7106
|
2.5
|
<5x10-6
|
14-16
|
6.0
|
15.0
|
23.0
|
GMP-7108
|
8.0
|
25.4
|
28.0
|
GMP-7110
|
10.0
|
25.4
|
33.0
|
GMP-7115
|
15.0
|
30.0
|
45.5
|
GMP-7206
|
3.0
|
<5x10-6
|
25-28
|
6.0
|
15.0
|
26.0
|
GMP-7208
|
8.0
|
25.4
|
32.0
|
GMP-7210
|
10.0
|
25.4
|
38.0
|
GMP-7215
|
15.0
|
30.0
|
53.0
|
|
|