* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download total internal reflection
Night vision device wikipedia , lookup
Ultrafast laser spectroscopy wikipedia , lookup
Optical flat wikipedia , lookup
Optical tweezers wikipedia , lookup
Diffraction grating wikipedia , lookup
Speed of light wikipedia , lookup
Fiber-optic communication wikipedia , lookup
Ultraviolet–visible spectroscopy wikipedia , lookup
Ellipsometry wikipedia , lookup
Silicon photonics wikipedia , lookup
Thomas Young (scientist) wikipedia , lookup
Astronomical spectroscopy wikipedia , lookup
Optical coherence tomography wikipedia , lookup
Optical aberration wikipedia , lookup
Photon scanning microscopy wikipedia , lookup
Surface plasmon resonance microscopy wikipedia , lookup
Nonlinear optics wikipedia , lookup
Magnetic circular dichroism wikipedia , lookup
Harold Hopkins (physicist) wikipedia , lookup
Nonimaging optics wikipedia , lookup
Ray tracing (graphics) wikipedia , lookup
Dispersion staining wikipedia , lookup
Refractive index wikipedia , lookup
Birefringence wikipedia , lookup
Retroreflector wikipedia , lookup
Chapter 26 Geometrical Optics (Lecture III) Dr. Jie Zou PHY 1161 1 Outline Features of refraction Optical illusions caused by refraction Total internal reflection Apparent depth Real world application: Optical fibers Dispersion and the rainbow Dr. Jie Zou PHY 1161 2 Features of Refraction When a ray of light enters a medium where its speed decreases, it is bent toward the normal. When a ray of light enters a medium where its speed increases, it is bent away from the normal. There is no change in direction of propagation if there is no change in index of refraction. The greater the change in index of refraction, the greater the change in propagation direction. If a ray of light goes from one medium to another along the normal, it is undeflected, regardless of the index of refraction. Dr. Jie Zou PHY 1161 3 Conceptual Checkpoint 26-4 A horizontal ray of light encounters a prism, as shown in the first diagram. After passing through the prism, is the ray (a) deflected upward, (b) still horizontal, or (c) deflected downward? Dr. Jie Zou PHY 1161 4 Optical Illusions Caused by Refraction Apparent depth: an object appears to be closer to the water’s surface than it really is. Dr. Jie Zou PHY 1161 5 Total Internal Reflection For angles of incidence greater than the critical angle, it is observed that all the light is reflected back into the water. This phenomenon is referred to as total internal reflection. The critical angle for total internal reflection can be found by sin c = n2/n1. Total internal reflection can only occur on the side of an interface that has the greater index of refraction. Dr. Jie Zou PHY 1161 6 Real World Applications Example: An optical fiber Dr. Jie Zou PHY 1161 7 Dispersion and the rainbow Dispersion: The “spreading out” of light according to color is known as dispersion. Explanation: Dr. Jie Zou The index of refraction for a given material depends on the frequency or wavelength of the light. In general, the higher the frequency, the higher the index of refraction. Violet light bends more than red light does when refracted by a given material. Light of different frequencies is bent at different angles when incident on a refracting material. PHY 1161 8 Formation of a rainbow Refraction of sunlight by a spherical raindrop. Dr. Jie Zou The formation of a rainbow. PHY 1161 9