Waveplate
CVI Melles Griot

ACWP achromatic waveplates are designed using two different substrate materials with compensating retardances and dispersions of retardance. Thus, the net birefringent phase shift is held constant over a 300-nm bandwidth with a polarization purity of better than 30:1.

Plots of the intensity transmission and the actual phase shift for each design versus wavelength can be found on the following page. These curves demonstrate the high degree of achromatization achievable by the dual material design.

For quarter waveplates, perfect retardance is a multiple of 0.25 waves. For half waveplates, perfect retardance is 0.5 waves, and perfect transmission through a linear polarizer parallel to the initial polarization state should be zero.

ACWP achromatic waveplates are comprised of thin, air-spaced crystal quartz and magnesium fluoride components which can handle laser energies up to 2 J/cm2. Three broadband wavelength ranges are available in both quarter and half wave retardances and in two different clear aperture sizes.
The waveplate fast axis is conveniently marked with a line on the housing for quick and easy reference.

Because both crystal quartz and MgF2 have positive birefringence, achromatic waveplates are sensitive to alignment and are recommended only for use with collimated beams.

ACWP achromatic waveplates offer a broader bandwidth than quartz waveplates and a higher damage threshold than polymer waveplates. They are ideal for use with broadband dye and tunable femtosecond lasers.