Waveplates are necessary elements for variable beam attenuators,
beamsplitters, and optical isolators. Waveplates (retardation
plates or phase shifters) are made from materials that exhibit
birefringence. The velocities of the extraordinary and ordinary
rays through the birefringent materials vary inversely with
their refractive indices. The difference in velocities gives
rise to a phase difference when the two beams recombine. In
the case of an incident linearly polarized beam this is given
by a=2pd(ne-no)/l(a-phase difference; d-thickness of waveplate;
ne, no-refractive indices of extraordinary and ordinary rays
respectively; l-wavelength). At any specific wavelength the
phase difference is governed by the thickness of the retarder.
Specifications
Materials:
Single crystal quartz
Optical Axis:
Normal to flat edge on circumference
of Retarder
Angle of Incidence:
0
Retardation
Tolerance:
l/500
Diameter Tolerance:
=0.00, 50.15 mm
Wavefront
distortion:
l/10 over central 90% of aperture
at 632.8 nm
Parallelism:
1 arc second
Surface Quality:
Ultrafine laser polish, 20-10 scratch
and dig
Coating:
Ultrahard antireflection coating on all air-quartz interfaces
Half wave plates are convenient means for reorienting
the polarization in order to meet the requirements for
a particular optical configuration,........
The thickness of the quarter waveplate is such that the
phase difference is 1/4 wavelength (ture-zero order) or
some multiple of 1/4 wavelength (multiple order).........
Moonlight Zero Order Waveplates are intended for those
applications where a thickness is required which corresponds
to a zero order phase difference .......
