Cu Phase Retarders
Phase retarder components are used in laser systems to convert a linearly polarized beam into a
circularly polarized beam.
In order to convert linear into circular polarization a total of one-quarter wave, or λ/4 retardation
(90°) is required.
Cu phase retarders are available only as the λ/4 type, and available sizes are detailed in table 12.201.
Copper-based phase retarders have a good cw laser damage threshold, and efficient cooling is
possible due to the high thermal conductivity of Cu.
Diameter : +0 / -0.1mm
Thickness : ± 0.1mm
Flatness : λ/40 over any 25mm dia test area
Reflectivity : > 98.5%
Wavelength range : 10.6μm only
Phase retardation : 90° +/- 6°
LIDT (normal inc.) : > 1000W/mm
(12.20A) The indicated item is made in volume and is relatively economical. This item is used
in Electrox lasers, where the beam is pre-converted to circular polarization before
leaving the laser box.
This phase retarder is also used in ULO Optics assembled phase retarder products
such as OPR25 and FPR25 (see data section 71).