With the two hypotenuses facing each
other, mount the prisms in a clamp with rubber-coated jaws to protect
the
prisms. Shine the laser so the light is totally internally
reflected by the first prism onto a screen. Tighten the clamp to
reduce the gap between the two prism faces until a transmitted beam
from the laser can be seen on the second screen. This illustrates
optical barrier penetration, analogous to quantum tunneling for
particles. It also shows how cube beamsplitters work.
The green laser is bright enough that chalk dust can be used to make
the transmitted beam visible.
