(Solved): A thin lens has a diameter d = 20 mm and a focal length of f = 100 mm. A point object P is located ...

A thin lens has a diameter d = 20 mm and a focal length of f = 100 mm. A point object P is located a distance le from the lens, where 4 »f, so the image P may be considered effectively to be at the focal plane of the lens. The object emits monochromatic light, i = 0.5 um. The light reaching the lens has intensity I. = 100 Ignore any losses due to reflection, scatter and absorption. 1 Find the radius and area of the Airy disk on the screen. [4 marks] (11) Approximately 84% of the total light intensity is diffracted into the Airy disk (the remainder 16 % is distributed in the circular diffraction pattern). Calculate the resulting image intensity 1: at P. [6 marks] Screen P Tef