a. Consider a laser radar emitting a Gaussian beam of diameter
20 cm with a wavelength of 2.1 μm. At distances of 50, 500, 5000,
and 50,000 meters, what is the focused beam diameter, and what is
the depth of field? Remember the depth of field is twice the
Rayleigh range of the waist diameter. Remember that in some cases
the solution may be impossible. Also re- member that there may be
two solutions, and it makes sense to pick...