Figure 9 is Bose's diagram of his polarization apparatus. The
transmitter is the box at left, and a spiral spring receiver ('R')
is visible on the right. One of the polarizers used by Bose was
a cut-off metal plate grating, consisting of a book (Bradshaw's
Railway Timetable, Figure 10) with sheets of tinfoil interleaved
in the pages. Bose was able to demonstrate that even an ordinary
book, without the tinfoil, is able to produce polarization of
the transmitted beam. The pages act as parallel dielectric sheets
separated by a small air gap.
with samples of jute in polarizing experiments. In one experiment,
he made a twisted bundle of jute and showed that it could be used
to rotate the plane of polarization. The modern equivalent component
may be a twisted dielectric waveguide. He further used this to
construct a macroscopic molecular model as an analogy to the rotation
of polarization produced by liquids like sugar solutions. Figure
11 shows Bose's diagram of the jute twisted-fiber polarization
rotator, and Figure 12 is a photograph of a surviving twisted-jute
polarizer at the Bose Institute.
Figure 7. Bose's diagram of his spiral-spring
receiver used for 5-mm radiation.