Shedding Light on Optics



9 Questions

What is the difference between geometric optics and physical optics?

What did Isaac Newton famously determine about white light?

What is the process where light interference is most commonly observed?

What is polarization in optics?

What is the Kapitsa-Dirac effect?

What is the function of corrective lenses?

What is the difference between birefringent and dichroic media?

What is the difference between classical optics and modern optics?

What is the human eye's function in optics?


Optics: The Branch of Physics that Studies Light

  • Optics is a branch of physics that studies the properties and behavior of light, including its interaction with matter and the construction of instruments that use or detect it.

  • Optics describes the behavior of visible, ultraviolet, and infrared light, and other forms of electromagnetic radiation such as X-rays, microwaves, and radio waves.

  • Geometric optics is a simplified model that treats light as a collection of rays that travel in straight lines and bend when they pass through or reflect from surfaces.

  • Physical optics is a more comprehensive model of light that includes wave effects such as diffraction and interference.

  • Quantum optics deals with the application of quantum mechanics to optical systems, and light is modeled as a collection of particles called photons.

  • Optics is relevant to and studied in many related disciplines including astronomy, engineering, photography, and medicine.

  • The earliest lenses, made from polished crystal, date back to 2000 BC, and lenses from Rhodes date around 700 BC.

  • Greek philosophers developed two opposing theories on how vision worked, the intromission theory and the emission theory.

  • In the early 17th century, Johannes Kepler expanded on geometric optics in his writings, covering lenses, reflection, and the principles of pinhole cameras.

  • In the late 1660s and early 1670s, Isaac Newton expanded Descartes's ideas into a corpuscle theory of light, famously determining that white light was a mix of colors that can be separated into its component parts with a prism.

  • Young's double-slit experiment showed that light followed the superposition principle, which is a wave-like property not predicted by Newton's corpuscle theory.

  • Classical optics is divided into two main branches: geometrical (or ray) optics and physical (or wave) optics.Overview of Optics

  • Geometric optics deals with the propagation of light rays in a straight line and their reflection and refraction from surfaces.

  • Spherical mirrors focus light at a common point, while other curved surfaces cause aberrations in the focus.

  • Refraction occurs when light passes through an area with a changing index of refraction, which allows for lenses and focusing of light.

  • The index of refraction of a medium is related to the speed of light in that medium.

  • Lenses produce converging or diverging light rays due to refraction, characterized by their focal length.

  • Ray tracing can be used to show how images are formed by a lens.

  • Light is considered to propagate as a wave in physical optics, which predicts phenomena such as interference and diffraction.

  • Many simplified approximations are available for analyzing and designing optical systems.

  • Numerical modeling techniques can be used to model the propagation of light in systems that cannot be solved analytically.

  • Superposition and interference of waves can result in constructive or destructive interference, producing bright and dark fringes in regular patterns.

  • Interferometry is the science of measuring these patterns, usually to make precise determinations of distances or angular resolutions.

  • The appearance of thin films and coatings is directly affected by interference effects.Overview of Physical Optics

  • Thin films can create low reflectivity over a broad band or extremely low reflectivity at a single wavelength using constructive interference.

  • Diffraction is the process where light interference is most commonly observed, and it was first described in 1665 by Francesco Maria Grimaldi.

  • X-ray diffraction uses atoms in a crystal with regular spacing at distances on the order of one angstrom.

  • Diffraction effects limit the ability of an optical detector to optically resolve separate light sources.

  • Dispersion occurs when different frequencies of light have different phase velocities, due either to material properties or to the geometry of an optical waveguide.

  • The separation of colors by a prism is an example of normal dispersion.

  • Polarization is a general property of waves that describes the orientation of their oscillations.

  • Circularly polarized waves can rotate rightward or leftward in the direction of travel, and which of those two rotations is present in a wave is called the wave's chirality.

  • Media that have different indexes of refraction for different polarization modes are called birefringent.

  • Media that reduce the amplitude of certain polarization modes are called dichroic.

  • Non-birefringent methods to rotate the linear polarization of light beams include the use of prismatic polarization rotators.

  • The atmosphere prevents optimal resolution from being achieved in the visible spectrum due to the atmospheric scattering and dispersion which cause stars to twinkle.Overview of Optics

  • Optics is the branch of physics that studies the properties and behavior of light.

  • Polarization effects occur when light interacts with materials that affect the orientation of the electric fields of the light waves.

  • Modern optics deals with the electromagnetic or quantum properties of light and includes subfields such as quantum optics, crystal optics, and non-linear optics.

  • Lasers emit light through a process called stimulated emission and have found utility in a variety of applications, including fiber-optic communication, laser printers, and laser hair removal.

  • The Kapitsa-Dirac effect causes beams of particles to diffract as a result of meeting a standing wave of light.

  • Optics is part of everyday life, with applications in eyeglasses, cameras, and optical communication, among others.

  • The human eye functions by focusing light onto the retina, which contains photoreceptor cells called rods and cones that are sensitive to different aspects of light.

  • Defects in vision can be corrected using corrective lenses, which are measured in diopters and can correct for presbyopia, hyperopia, myopia, and astigmatism.

  • Optical illusions are characterized by visually perceived images that differ from objective reality and can be caused by physical effects, physiological effects, or cognitive illusions.

  • Compound optical instruments, such as microscopes and telescopes, combine mirrors, prisms, and lenses for practical uses.

  • Optics has practical applications in illumination engineering, photonics, and optoelectronics, among others.

  • Nonlinear optics is an area of research that has developed in the last several decades due to advances in laser technology.


Test your knowledge on the fascinating field of Optics, the branch of physics that studies light and its properties. From geometric optics to physical optics, discover the principles and theories that govern the behavior of light and its interaction with matter. Learn about the history of optics, including the development of lenses and the opposing theories of vision in Ancient Greece. Explore the practical applications of optics in everyday life, from eyeglasses to lasers, and delve into subfields such as quantum optics and non-linear optics. Take

Ready to take the quiz?

Play Quiz