<P> The transmission coefficient for FTIR is highly sensitive to the spacing between the third medium and the second medium (the function is approximately exponential until the gap is almost closed), so this effect has often been used to modulate optical transmission and reflection with a large dynamic range . </P> <P> A lesser - known aspect of total internal reflection is that the reflected light has an angle dependent phase shift between the reflected and incident light . Mathematically this means that the Fresnel reflection coefficient becomes a complex rather than a real number . This phase shift is polarization dependent and grows as the incidence angle deviates further from the critical angle toward grazing incidence . </P> <P> The polarization dependent phase shift is long known and was used by Fresnel to design the Fresnel rhomb which allows one to transform circular polarization to linear polarization and vice versa for a wide range of wavelengths (colors), in contrast to the quarter wave plate . The polarization dependent phase shift is also the reason why TE and TM guided modes have different dispersion relations . </P> <Ul> <Li> Total internal reflection is the operating principle of optical fibers, which are used in endoscopes and telecommunications . </Li> <Li> Total internal reflection is the operating principle of automotive rain sensors, which control automatic windscreen / windshield wipers . </Li> <Li> Another application of total internal reflection is the spatial filtering of light . </Li> <Li> Prisms in binoculars use total internal reflection, rather than reflective coatings, to fold optical paths and show erect images . </Li> <Li> Some multi-touch screens use frustrated total internal reflection in combination with a camera and appropriate software to pick up multiple targets . </Li> <Li> Gonioscopy employs total internal reflection to view the anatomical angle formed between the eye's cornea and iris . </Li> <Li> A gait analysis instrument, CatWalk XT, uses frustrated total internal reflection in combination with a high speed camera to capture and analyze footprints of laboratory rodents . </Li> <Li> Optical fingerprinting devices use frustrated total internal reflection in order to record an image of a person's fingerprint without the use of ink . </Li> <Li> A total internal reflection fluorescence microscope uses the evanescent wave produced by TIR to excite fluorophores close to a surface . This is useful for the study of surface properties of biological samples . </Li> <Li> Total internal reflection is the operating principle of LED Light Panels . This technology utilizes LGPs (Light Guide Plates) as the vehicle for transmitting light over large areas . By etching a grid pattern on the second surface of the LGP, frustrated total internal reflection occurs allowing the light to escape the LGP as visible illumination . </Li> <Li> Diamonds shine brightly due to total internal reflection . </Li> <Li> Total internal reflection (TIR) are used on lighting industry to manage narrow distribution (NEMA classification) for floodlight . </Li> </Ul>

Physics investigatory project for class 12 on total internal reflection