Total Internal Reflection

This interactive simulator explores Total Internal Reflection in Optics & Light. Find the critical angle. Fiber optics analogy. Use the controls to change the scenario; watch the visualization and any graphs or readouts to connect the model with lectures, labs, and homework.

Who it's for: Best once you already know the basic definitions and want to build intuition. Typical context: Optics & Light.

Key terms

  • total
  • internal
  • reflection
  • total internal reflection
  • optics
  • light

How it works

For n₁ > n₂, there is a critical angle θ_crit = arcsin(n₂/n₁). Rays incident from the denser side at θᵢ > θ_crit undergo total internal reflection instead of refracting out. Optical fibers trap light by TIR at the core–cladding interface.

Key equations

n₁ sin θᵢ = n₂ sin θₜ   (Snell)
θ_crit = arcsin(n₂/n₁)   when n₁ > n₂