Very short pulses of high-intensity laser beams are used to repair detached portions of the retina of the eye.

Very short pulses of high-intensity laser beams are used to repair detached portions of the retina of the eye. The brief pulses of energy absorbed by the retina welds the detached portion back into place. In one such procedure, a laser beam has a wavelength of 815 , and delivers 221 , of power spread over a circular spot 536 , in diameter. The vitreous humor (the transparent fluid that fills most of the eye) has an index of refraction of 1.34. What is the maximum value of the electric field in the laser beam?