Question

(a) Laser pulses of femtosecond (10−15) duration can be produced but for such brief pulses it makes no sense to speak of the pulse’s color. To see this, compute the time duration of a laser pulse whose range of frequencies covers the entire visible spectrum (4.0 × 1014 Hz to 7.5 × 1014 Hz). (4 points) (b) Now suppose that uncertainty in frequency of such laser pulses is found of the order of 1012 Hz. Find the order of uncertainty in (i) wavelength. (2 points) (ii) energy. (2 points) (iii) time period of such pulses.

Answer 1