OPR25 Offset Phase Retarder Unit

Model OPR25 is an offset (2-mirror) phase retarder unit intended for applications where an in-line
unit is not required. The unit contains one copper, 90° (λ/4) phase retarder and one periscope mirror
used to reflect the beam parallel to its original path, but separated by 60.0mm. OPR25 is capable
of withstanding high CO2 CW laser powers and has a 33mm clear aperture. The mirrors are separately
Technical specifications
Dimensions : See figure 71.31.
Fittings : Standard free-rotating coupling rings with 52 x 1.5 pitch threads.
Cooling : Separate 6/4 size input/output water fittings serve each mirror.
Alignment : Factory set to <2′. User-adjustable.
Phase retardation : 90±5° (λ/4).
Clear aperture : 33mm diameter.
Max power : 5kW CW
Wavelength : 10.6μm.
Associated equipment
Model OPR25 is a direct fit to OPG optical piping (Section 61.1). Additionally, the unit will attach
to lateral adjustment units LAU25 (Section 72.1) and LAM25 (Section 72.2). The user may fit
OPR25 between two male threads, size 52.0 dia. x 1.5 pitch x 104.0 long where:

offset phase retarder


1) The separation between ‘pipe ends’ in the direction of the optical axis is 104.0mm.
2) The separation of thread centres is 60.0mm.
3) The direction of separation of thread centres is at 45° to the plane of the incident linear
polarization. See figure 71.32.

offset diagram