Question

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 810 nm and delivers 250 mW of power spread over a circular spot 510 μm in diameter. The vitreous humor (the transparent fluid that fills most of the eye) has an index of refraction of 1.34.

1) If the laser pulses are each 1.50 ms long, how much energy is delivered to the retina with each pulse?

2) What average pressure would the pulse of the laser beam exert at normal incidence on a surface in air if the beam is fully absorbed?

3) What are the wavelength of the laser light inside the vitreous humor of the eye?

4) What is the frequency of the laser light inside the vitreous humor of the eye?

5) What is the maximum value of the electric field in the laser beam?

6) What is the maximum value of the magnetic field in the laser beam?

Answer 1