The frequency of microwave radiation is too high to be detected directly
easily, since a typical laboratory oscilloscope would work only up to
Mhz. The energy of the photons is too small to be detected
with your eye, photography, or a photoelectric device.
To ``see'' the microwaves in this experiment,
you will use a diode that
will rectify the oscillation and produce a current. This DC signal is
approximately proportional to the energy incident on the diode, and it
is detected by a simple meter in the instrument in the optics lab. The
meter has a variable attenuator to adjust its sensitivity for different
circumstances.