Total Internal Reflection

Total Internal Reflection (TIR) is the principle of signal transmissions in optical fibers. The understanding of the critical angle is important to understand the TIR.

Do you know at what time the incident angle is called the critical angle? If no I will explain here, if yes then good, check my explanation and verify for the same.

So let’s start;

  1. We have two medium with different refractive indices, one medium has larger than the other one. For example, let one is glass and second is the air.
  2. Light ray travel from glass to the air.
  3. In the rare medium, light ray goes away from the normal at the interface after refraction.
  4. we choose different incident angles till that light ray doesn’t reflect into the same medium.

Total internal reflection

In this picture, you can see, the incident light ray of red color get refracted, bending away from the normal. As you increase the incident angle the refracted ray goes away from the normal. At one particular incident angle, the refracted ray passes through the interface of two medium. This incident angle at which refracted angle become 900 known as the critical angle.

This is also known as a limiting case for total internal reflection. At this time you can apply the Snell’s law to find the critical angle. This is the ratio of refractive indices of the second medium to the first one.

The total internal reflection phenomenon we use in the optical fiber for the transmission of the light signal. If you want to read more about it you can download the details by click this link, click here  . Total internal reflection concept also used for fluorescence and various other studies.