The total reflection of a beam of light at the interface of one medium and another medium of lower refractive index, when the angle of incidence to the second medium exceeds a specific critical angle .
If a beam of light passing through a medium A (say glass) strikes the boundary to a medium B of lower refractive index (say air) with a small angle of incidence i, part will be refracted, with an angle of refraction r, and part will be reflected (see illustration a). If i is increased it will reach a critical angle c, at which r = 90° (see illustration b). If i is now increased further, no refraction can occur and all the light energy is reflected by the interface (see illustration c). This total internal reflection occurs when c (given by nsinc = 1) is exceeded (n is the refractive index of A relative to B). The critical angle of optical glass is usually about 40° and total internal reflection is made use of by incorporating prisms in some optical instruments instead of mirrors.
Total internal reflection
- directrix
- discharge
- discontinuous function
- disintegration
- disintegration constant
- diskette
- dislocation
- disordered solid
- disperse phase
- dispersion
- dispersion forces
- dispersive power
- displacement
- distortion
- distributive law
- diurnal
- divergence
- divergence theorem
- divergent series
- diverging lens or mirror
- dl-from
- DLA
- domain
- donor
- doping