Evanescent waves

The animations below show the incident, reflected, transmitted, and total fields, over the course of a cycle, both for normal refraction,

   

and for total internal reflection:

   

Evanescent waves in transmission after TIR

At critical angle

1. https://web.stanford.edu/~ajlucas/Evanescent%20Waves.pdf
2. https://physics.stackexchange.com/questions/52555/does-light-reflect-if-incident-at-exactly-the-critical-angle/338428#338428