The polarization direction of the incident light can be adjusted by a [lambda]/2 wave plate
. While incident light passes through the [lambda]/2 wave plate
, the mirrors and the notch filter will affect its polarization direction.
The wax and PTFE particles in the above photos appear white when viewed with crossed polars, but colors can be brought out by adding a wave plate
to the light path.
A disadvantage of a standard birefringent quarter wave plate
is well known: it can operate only at a fixed wavelength.
It's a dual-beam imaging polarimeter, which is a standard professional design with a calcite analyzer prism and a rotatable wave plate
. It creates two images for every star, and the brightness ratios of the star pairs in four images taken at different polarization angles reveal the magnitude and direction of polarization to a precision limited only by the number of photons collected.
The easySTED wave plate
is a birefringent phase retarding element consisting of four segments of different orientation (Figure 2) to the effect that it leaves the polarization of the excitation light mostly unchanged, while the polarization of the STED beam is modified such that it renders a focal doughnut [17,18] (see Figure 2).
Two quarter wave plates
(QWP1, QWP2), one half wave plate
(HWP), and a polarization beam splitter (PBS) were used in the resonator.
(1) Let the N identical copies of the output photon pass through the horizontal-polarization wave plate
, and record the number [n.sub.0].
Plate properties and design data for the Alpine Wave Plate
may be found in the Southern Building Code International evaluation report .