Laser and Fiber Optic 6A44.40
Optics Geometrical Optics Total Internal Reflection

Concept

This apparatus demonstrates total internal reflection of a laser beam within various acrylic rods and a long fiber optic cable. For acrylic, which has about the same index of refraction as water ($n=1.33$), the critical angle is ~ 49°. For the fiber optic cable, which has an internal core ($n=1.5$) and cladding ($n=1.4$), the critical angle is ~42°.

Procedure

  1. Use the green laser pointer to bounce a beam of light through the acrylic pieces.
  2. Repeat using the 19 meters of fiber optic cable.

Equipment

  1. Green Laser and Case
  2. Acrylic Pieces
  3. Fiber Optic Cable (19 m)
  4. Support Stand with 3’ Rod
  5. (3) 2-Prong Rod Clamps