Question

In charged particle detectors we often use optical fibers to guide light emitted from charged particles (through scintillation or Cherenkov radiation) in one section of the detector to optically sensitive photodetector devices at another section of the detector, so that the emitted light can be detected, recorded and later analyzed. After entering the optical fiber (you can assume the light enters from a region of just air), the light is guided from one end of the optical fiber to the other through a sequence of "bounces" within the fiber due to total internal reflection. A simplistic depiction of an optical fiber is shown below: Consider an optical fiber with index of refraction1.55 (for light of wavelength), surrounded by a plastic sheath with n-1.51 (for light of wavelength A). A light ray is incident on one end of the fiber at an angle 8. The ray undergoes total internal reflection at point A, where it encounters the fiber core-sheath boundary (a) Assuming there is no loss of light through that boundary, what is the maximum value of 0 that allows total internal reflection at A? (b) what is the maximum value of ? for light of wavelength ?, for which the index of refraction is reduced by 5% in both regions (core and sheath)?

Answer 1

Find the answer in the image attached below.

Here so the maximun Valuee. β that alloos tota) n/ '.ss('-S.) ะ thun 1.4725 16ο loo 0 10.4)