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Polarizer
 
Union Optic provides the following polarizers with four materials include a-BBO, Calcite, Quartz and YVO4 for widest spectrum and high polarization application.
 
Polarizer
Material
Illustration
Properties and Application
Glan-Taylor
Polarizer
a-BBO(190-3500nm)
Calcite(350-2300nm)
YVO4(500-4000nm)
  • Air-spaced
  • Close to Brewsters Angle cutting
  • For medium power application
Glan-Laser
Polarizer
a-BBO(190-3500nm)
Calcite(350-2300nm)
YVO4(500-4000nm)
  • Air-spaced.
  • Close to Brewsters angle cutting
  • Mounted with escape window
  • Suitable for high power applications
Glan-Thompson
Polarizer
Calcite(400-2300nm)
  • Cemented
  • Suitable for low power applications
  • Wide acceptance angle
Brewster
Polarizer
Calcite(350-2300nm)
YVO
4(500-4000nm)
  • Transmission Efficiency T>98%
  • High damage threshold
  • No AR coating needed
Wollaston
Polarizer
Calcite(400-2300nm)
YVO4(500-4000nm)
Quartz(400-2300nm)
  • Cemented
  • Separate ordinary and extraordinary beams at certain angle
  • Suitable for low power application and where the large deviation is required
Rochon
Polarizer
YVO4(500-4000nm)
Quartz(400-2300nm)
  • Cemented
  • Split the ordinary and extraordinary ray, but only ordinary beam is deviated
  • Suitable for low power application
Polarization
Beamsplitter Plate
BK7
  • Split the S beam and P beam
  • Brewster angle of incidence
  • Suitable for high power apolication
Polarization
Beamsplitter Cube
BK7, SF glass
  • Split the S beam and P beam
Polarization Rotator
Quartz
  • Rotate polarization state
Optical Isolator
BK7, Quartz
  • Block optical feedback
  • Passive isolation of linearly polarized light
  • High isolation
Lateral Displacement Polarization Beamsplitter
BK7
  • Split incident beam into two displaced parallel beams
  • Waveplate can be added to manage polarization state
  • NOA61 cemented
Depolarizer
Quartz
  • Eliminate polarization effect
 
Comparison of the four materials
 
  
YVO4
Calcite
a-BBO
Quartz
Transparency
500-4000nm
350-2300nm
200-3500nm
200-2300nm
Crystal Class (Uniaxial)
Positive
no=na=nb,ne=nc
Negative
no=na=nb,ne=nc
Negative
no=na=nb,ne=nc
Positive
no=na=nb,ne=nc
Mohs Hardness
5
3
4.5
7
Thermal Expansion Coefficient
aa=4.43x10-6/K
ac=11.37x10
-6/K
aa=24.39x10-6/K
ac=5.68x10
-6/K
aa=4x10-6/K
ac=36x10
-6/K
aa=6.2x10-6/K
ac=10.7x10
-6/K
Hygroscopic Susceptibility
Low
Low
Low
Low
 
Note:
 

Classic Glan Laser type prisms (PGT, PGM, and PGL Series) suffer a small, unavoidable loss at the two internal calcite-air interfaces. This loss is avoided in the Brewster type (PBI Series) by presenting the P polarized transmitted beam to these interfaces at Brewsters angle. The result is a high power, low loss polarizer that does not need AR coating.

The user should be aware of two important considerations in the use of Brewster Polarizer (PBI polarizers). First, stringent angular acceptance requirements dictate use with collimated beams only. Second, the transmitted beam has a relatively large parallel beam displacement with respect to the incident beam.