Question

A laser emits a cylindrical beam of light 2.6 mm in diameter.

If the average power of the laser is 2.0 mW, what is the rms value of the electric field in the
laser beam?

Erms=___kV/m

Answer 1

Given that
radius r = 2.3 /2 = 1.30*10-3m
Power P = 2.00*10-3W



We have the formula for the average power is
P =ceo Erms2(4pr2)
Erms =v{P/(ceo (4pr2))}

Here c =3*10^8 m/s
eo = 8.85*10^-12 C2/N.m2

Erms = Sqrt ((2.00*10-3)/(8.85*10^-12(4p*1.30*10-3^2)))

Erms = 3262.083 kV/m