A 190 MW laser pulse is focused with a lens to a diameter of 2.3 μm.
(a) What is the intensity of the laser beam at this diameter? Remember that the power (and intensity) of the laser beam is concentrated in a circular spot, and be careful with your units. 1 μm = 10-6m. You are going to get some remarkably large values for this problem. Laser beams can be tremendously powerful, which is why there are safety concerns.
(b) What is the amplitude of the electric field when the beam is focused at this diameter?