Polarized Light In Optics And Spectroscopy PdfBy Patrick M. In and pdf 21.05.2021 at 05:21 8 min read
File Name: polarized light in optics and spectroscopy .zip
- Controllable optical activity with non-chiral plasmonic metasurfaces
- Optical rotation
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Controllable optical activity with non-chiral plasmonic metasurfaces
Light , electromagnetic radiation that can be detected by the human eye. Within that broad spectrum the wavelengths visible to humans occupy a very narrow band, from about nanometres nm; billionths of a metre for red light down to about nm for violet light. The spectral regions adjacent to the visible band are often referred to as light also, infrared at the one end and ultraviolet at the other.
The speed of light in a vacuum is a fundamental physical constant , the currently accepted value of which is exactly ,, metres per second, or about , miles per second. The physicist is interested in the physical properties of light, the artist in an aesthetic appreciation of the visual world. Through the sense of sight, light is a primary tool for perceiving the world and communicating within it.
Light from the Sun warms the Earth , drives global weather patterns, and initiates the life-sustaining process of photosynthesis. Indeed, light provides a window on the universe, from cosmological to atomic scales.
Almost all of the information about the rest of the universe reaches Earth in the form of electromagnetic radiation. By interpreting that radiation, astronomers can glimpse the earliest epochs of the universe, measure the general expansion of the universe, and determine the chemical composition of stars and the interstellar medium. Just as the invention of the telescope dramatically broadened exploration of the universe, so too the invention of the microscope opened the intricate world of the cell.
The analysis of the frequencies of light emitted and absorbed by atoms was a principal impetus for the development of quantum mechanics. Atomic and molecular spectroscopies continue to be primary tools for probing the structure of matter, providing ultrasensitive tests of atomic and molecular models and contributing to studies of fundamental photochemical reactions.
Light transmits spatial and temporal information. This property forms the basis of the fields of optics and optical communications and a myriad of related technologies, both mature and emerging. Technological applications based on the manipulations of light include lasers , holography , and fibre-optic telecommunications systems. In most everyday circumstances, the properties of light can be derived from the theory of classical electromagnetism , in which light is described as coupled electric and magnetic fields propagating through space as a traveling wave.
However, this wave theory, developed in the midth century, is not sufficient to explain the properties of light at very low intensities.
At that level a quantum theory is needed to explain the characteristics of light and to explain the interactions of light with atoms and molecules. In its simplest form, quantum theory describes light as consisting of discrete packets of energy , called photons.
However, neither a classical wave model nor a classical particle model correctly describes light; light has a dual nature that is revealed only in quantum mechanics. This surprising wave-particle duality is shared by all of the primary constituents of nature e. Since the midth century, a more comprehensive theory of light, known as quantum electrodynamics QED , has been regarded by physicists as complete. QED combines the ideas of classical electromagnetism, quantum mechanics, and the special theory of relativity.
This article focuses on the physical characteristics of light and the theoretical models that describe the nature of light. Its major themes include introductions to the fundamentals of geometrical optics, classical electromagnetic waves and the interference effects associated with those waves, and the foundational ideas of the quantum theory of light.
More detailed and technical presentations of these topics can be found in the articles optics , electromagnetic radiation , quantum mechanics , and quantum electrodynamics. While there is clear evidence that simple optical instruments such as plane and curved mirrors and convex lenses were used by a number of early civilizations, ancient Greek philosophers are generally credited with the first formal speculations about the nature of light.
The conceptual hurdle of distinguishing the human perception of visual effects from the physical nature of light hampered the development of theories of light. Contemplation of the mechanism of vision dominated these early studies. Pythagoras c. Epicurus c. Euclid c. Ptolemy c. With the decline of the Greco-Roman realm, scientific progress shifted to the Islamic world. By , the Pythagorean model of light had been abandoned, and a ray model, containing the basic conceptual elements of what is now known as geometrical optics, had emerged.
He also studied the mathematical properties of the reflection of light from spherical and parabolic mirrors and drew detailed pictures of the optical components of the human eye. Bacon studied the propagation of light through simple lenses and is credited as one of the first to have described the use of lenses to correct vision.
Light Article Media Additional Info. Article Contents. Print print Print. Table Of Contents. While every effort has been made to follow citation style rules, there may be some discrepancies.
Please refer to the appropriate style manual or other sources if you have any questions. Facebook Twitter. Give Feedback External Websites.
Let us know if you have suggestions to improve this article requires login. External Websites. Articles from Britannica Encyclopedias for elementary and high school students. See Article History. Alternative Titles: optical spectrum, visible radiation, visible spectrum. When white light is spread apart by a prism or a diffraction grating, the colours of the visible spectrum appear. The colours vary according to their wavelengths. Violet has the highest frequencies and shortest wavelengths, and red has the lowest frequencies and the longest wavelengths.
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English Franciscan philosopher and educational reformer Roger Bacon shown in his observatory at the Franciscan monastery, Oxford, England engraving c. Load Next Page.
Light , electromagnetic radiation that can be detected by the human eye. Within that broad spectrum the wavelengths visible to humans occupy a very narrow band, from about nanometres nm; billionths of a metre for red light down to about nm for violet light. The spectral regions adjacent to the visible band are often referred to as light also, infrared at the one end and ultraviolet at the other. The speed of light in a vacuum is a fundamental physical constant , the currently accepted value of which is exactly ,, metres per second, or about , miles per second. The physicist is interested in the physical properties of light, the artist in an aesthetic appreciation of the visual world. Through the sense of sight, light is a primary tool for perceiving the world and communicating within it. Light from the Sun warms the Earth , drives global weather patterns, and initiates the life-sustaining process of photosynthesis.
We apologize for the inconvenience...
Optical rotation , also known as polarization rotation or circular birefringence , is the rotation of the orientation of the plane of polarization about the optical axis of linearly polarized light as it travels through certain materials. Circular birefringence and circular dichroism are the manifestations of optical activity. Optical activity occurs only in chiral materials, those lacking microscopic mirror symmetry. Unlike other sources of birefringence which alter a beam's state of polarization, optical activity can be observed in fluids.