Optics

The bouncing of light off a surface. The law of reflection states that the angle of incidence equals the angle of reflection, measured from the normal to the surface. Reflection can be specular (mirror-like, from smooth surfaces) or diffuse (scattered, from rough surfaces).

The bending of light as it passes from one transparent medium to another with a different optical density. Snell's law (n1 sin theta1 = n2 sin theta2) quantifies the relationship between the angles of incidence and refraction and the refractive indices of the two media.

The spreading and bending of light waves as they pass through narrow openings or around obstacles. Diffraction becomes significant when the size of the aperture or obstacle is comparable to the wavelength of light, and it limits the resolving power of optical instruments.

The phenomenon that occurs when two or more coherent light waves overlap, resulting in constructive interference (brighter regions where waves are in phase) or destructive interference (darker regions where waves are out of phase).

The restriction of light wave oscillations to a single plane. Unpolarized light vibrates in all directions perpendicular to its direction of travel, while polarized light vibrates in only one plane. Polarization can be achieved by filters, reflection, or scattering.

When light traveling in a denser medium hits the boundary with a less dense medium at an angle greater than the critical angle, all light is reflected back into the denser medium rather than being refracted. This principle is the foundation of fiber optic technology.

The principle that light exhibits both wave-like properties (interference, diffraction, polarization) and particle-like properties (photoelectric effect, Compton scattering). In quantum optics, light is described as consisting of photons that carry quantized energy proportional to their frequency (E = hf).

Lenses are transparent optical elements that refract light to converge (convex lenses) or diverge (concave lenses) rays. The thin lens equation (1/f = 1/do + 1/di) relates the focal length to the object and image distances, enabling the design of cameras, eyeglasses, and telescopes.

The full range of electromagnetic radiation, ordered by wavelength or frequency. Visible light occupies only a small portion (approximately 380-700 nm), flanked by ultraviolet and infrared. All electromagnetic waves travel at the speed of light in a vacuum (approximately 3 x 10^8 m/s).

Light Amplification by Stimulated Emission of Radiation. A laser produces coherent, monochromatic, and highly directional light through the process of stimulated emission, where excited atoms release photons that are identical in phase, frequency, and direction to the stimulating photon.