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You want to couple the energy of an argon-ion laser beam of wavelength 2 = 514 nm into a fiber optic cable. Refractive indices of the fibre optic cable are 1.45 for the core and 1.42 for the cladding. The beam of the laser has a cross sectional area of 12.47 mm with negligible divergence and the entire beam has to be coupled into a diameter of 20 um (fiber core). A convergent lens could be used to couple the laser beam into the fiber. a) Calculate the focal length of the lens to be used. b) Calculate the angle of convergence of the focused laser beam. c) How does the angle of convergence calculated in part (b) compare to the acceptance angle of the fiber? What would you conclude