TBU30 Conventional Type

IntroductionTBU Beam Splitter
Model TBU30 beamsplitter uses a ZnSe partially reflecting component set at 45 degrees incidence
to the laser beam. The beamsplitter component must therefore be carefully chosen to suit the state
of polarization of the incident laser beam.
(In this respect model TBU30 differs from the ‘polarization-insensitive’ beamsplitter units described
elsewhere in data section 70.00).
The physical dimensions of model TBU30 are chosen such that this unit may be used to replace a
TM25 or TM30 mirror block (data section 62.0). This feature allows retro-fitting of a beamsplitter
or beam-sampling unit at a location within a laser system where previously a mirror was installed.
Technical specifications
Dimensions : See Figure 70.121
Construction : Aluminium, black anodised.
Connections : Via free-rotating coupling rings, 52.0 dia. x 1.5mm pitch, female thread.
Cooling : Air cooled.
Clear aperture : 32.0 mm diameter.
Optics : ZnSe 50mm dia x 4mm thick.
Max CW power : 2000W (estimated).
Coating options
The partially reflective coating is chosen to suit the application and the state of polarization of the
incident beam
Model TBU30 would normally be used with a linearly polarized incident beam, and so the standard
beamsplitter coating will be one of:
AR/50%, 45-deg, P-POL or AR/50%, 45-deg, S-POL,
the choice depending upon the relative azimuth of the incident linear polarization.
If used in a beam-sampling role, the user may select some suitable reflectivity to suit the application.
Example coatings might be, say:
AR/1%, 45-deg or AR/99%, 45-deg
depending upon whether the transmitted or reflected beam is to be the ‘sample’ for analysis or power
Model TBU30 is provided with tilt-adjustment screws to enable accurate alignment of the reflected
beam. The transmitted beam is not affected by tilt of the beamsplitter component.
Associated equipment
TBU30 is a direct fit to OPG optical piping (data section 61.1).
It is a direct mechanical replacement for either of mirror blocks TM25 or TM30 in applications where
sampling or beam injection is required at an existing beam-fold location.
Align TBU30 by means of crosswire MX25 (data section 64).

TBU30 Beam Splitter