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TSMC. Taiwan Semiconductor Manufacturing Company Limited ( TSMC; also called Taiwan Semiconductor) [4] [5] is a Taiwanese multinational semiconductor contract manufacturing and design company. It is the world's second-most valuable semiconductor company, [6] the world's largest dedicated independent ("pure-play") semiconductor foundry, [7] and ...
- 73,090 (2022)
- US$73.67 billion (2022)
Lidar (/ˈlaɪdɑːr/, also LIDAR, LiDAR or LADAR, an acronym of "light detection and ranging"[1] or "laser imaging, detection, and ranging"[2]) is a method for determining ranges by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the receiver. Lidar may operate in a fixed direction (e ...
- Terminology
- Fundamentals
- Design
- Laser Physics
- Modes of Operation
- History
- Types and Operating Principles
- Uses
- Safety
- Further Reading
The first device using amplification by stimulated emission operated at microwave frequencies, and was called a maser, for "microwave amplification by stimulated emission of radiation". When similar optical devices were developed they were first known as optical masers, until "microwave" was replaced by "light" in the acronym, to become laser. Toda...
Modern physics describes light and other forms of electromagnetic radiation as the group behavior of fundamental particles known as photons. Photons are released and absorbed through electromagnetic interactions with other fundamental particles that carry electric charge. A common way to release photons is to heat an object; some of the thermal ene...
A laser consists of a gain medium, a mechanism to energize it, and something to provide optical feedback. The gain medium is a material with properties that allow it to amplify light by way of stimulated emission. Light of a specific wavelength that passes through the gain medium is amplified (power increases). Feedback enables stimulated emission ...
Electrons and how they interact with electromagnetic fields are important in our understanding of chemistry and physics.
A laser can be classified as operating in either continuous or pulsed mode, depending on whether the power output is essentially continuous over time or whether its output takes the form of pulses of light on one or another time scale. Of course, even a laser whose output is normally continuous can be intentionally turned on and off at some rate to...
Foundations
In 1917, Albert Einstein established the theoretical foundations for the laser and the maser in the paper "Zur Quantentheorie der Strahlung" ("On the Quantum Theory of Radiation") via a re-derivation of Max Planck's law of radiation, conceptually based upon probability coefficients (Einstein coefficients) for the absorption, spontaneous emission, and stimulated emission of electromagnetic radiation. In 1928, Rudolf W. Ladenburg confirmed the existence of the phenomena of stimulated emission a...
Maser
In 1951, Joseph Weber submitted a paper on using stimulated emissions to make a microwave amplifier to the June 1952 Institute of Radio Engineers Vacuum Tube Research Conference at Ottawa, Ontario, Canada. After this presentation, RCA asked Weber to give a seminar on this idea, and Charles H. Townesasked him for a copy of the paper. In 1953, Charles H. Townes and graduate students James P. Gordon and Herbert J. Zeiger produced the first microwave amplifier, a device operating on similar princ...
Laser
In April 1957, Japanese engineer Jun-ichi Nishizawa proposed the concept of a "semiconductor optical maser" in a patent application. That same year, Charles H. Townes and Arthur Leonard Schawlow, then at Bell Labs, began a serious study of infrared "optical masers". As ideas developed, they abandoned infrared radiation to instead concentrate on visible light. In 1958, Bell Labs filed a patent application for their proposed optical maser; and Schawlow and Townes submitted a manuscript of their...
Gas lasers
Following the invention of the HeNe gas laser, many other gas discharges have been found to amplify light coherently.Gas lasers using many different gases have been built and used for many purposes. The helium–neon laser (HeNe) can operate at many different wavelengths, however, the vast majority are engineered to lase at 633 nm; these relatively low-cost but highly coherent lasers are extremely common in optical research and educational laboratories. Commercial carbon dioxide (CO2) lasers ca...
Solid-state lasers
Solid-state lasers use a crystalline or glass rod that is "doped" with ions that provide the required energy states. For example, the first working laser was a ruby laser, made from ruby (chromium-doped corundum). The population inversion is maintained in the dopant. These materials are pumped optically using a shorter wavelength than the lasing wavelength, often from a flash tube or another laser. The usage of the term "solid-state" in laser physics is narrower than in typical use. Semicondu...
Fiber lasers
Solid-state lasers or laser amplifiers where the light is guided due to the total internal reflection in a single mode optical fiber are instead called fiber lasers. Guiding of light allows extremely long gain regions providing good cooling conditions; fibers have a high surface area to volume ratio which allows efficient cooling. In addition, the fiber's waveguiding properties tend to reduce the thermal distortion of the beam. Erbium and ytterbiumions are common active species in such lasers...
When lasers were invented in 1960, they were called "a solution looking for a problem". Since then, they have become ubiquitous, finding utility in thousands of highly varied applications in every section of modern society, including consumer electronics, information technology, science, medicine, industry, law enforcement, entertainment, and the m...
Even the first laser was recognized as being potentially dangerous. Theodore Maiman characterized the first laser as having the power of one "Gillette" as it could burn through one Gillette razor blade. Today, it is accepted that even low-power lasers with only a few milliwatts of output power can be hazardous to human eyesight when the beam hits t...
Books
1. Bertolotti, Mario (1999, trans. 2004). The History of the Laser. Institute of Physics. ISBN 0-7503-0911-3. 2. Bromberg, Joan Lisa (1991). The Laser in America, 1950–1970. MIT Press. ISBN 978-0-262-02318-4. 3. Csele, Mark (2004). Fundamentals of Light Sources and Lasers. Wiley. ISBN 0-471-47660-9. 4. Koechner, Walter (1992). Solid-State Laser Engineering. 3rd ed. Springer-Verlag. ISBN 0-387-53756-2. 5. Siegman, Anthony E. (1986). Lasers. University Science Books. ISBN 0-935702-11-3. 6. Silf...
Periodicals
1. Applied Physics B: Lasers and Optics (ISSN 0946-2171) 2. IEEE Journal of Lightwave Technology (ISSN 0733-8724) 3. IEEE Journal of Quantum Electronics (ISSN 0018-9197) 4. IEEE Journal of Selected Topics in Quantum Electronics (ISSN 1077-260X) 5. IEEE Photonics Technology Letters (ISSN 1041-1135) 6. Journal of the Optical Society of America B: Optical Physics (ISSN 0740-3224) 7. Laser Focus World (ISSN 0740-2511) 8. Optics Letters (ISSN 0146-9592) 9. Photonics Spectra (ISSN 0731-1230)
Fibonacci sequence. A tiling with squares whose side lengths are successive Fibonacci numbers: 1, 1, 2, 3, 5, 8, 13 and 21. In mathematics, the Fibonacci sequence is a sequence in which each number is the sum of the two preceding ones. Numbers that are part of the Fibonacci sequence are known as Fibonacci numbers, commonly denoted Fn .
Classification. ALS is a motor neuron disease, which is a group of neurological disorders that selectively affect motor neurons, the cells that control voluntary muscles of the body. [3] Other motor neuron diseases include primary lateral sclerosis (PLS), progressive muscular atrophy (PMA), progressive bulbar palsy, pseudobulbar palsy, and ...
The domestic cat has a smaller skull and shorter bones than the European wildcat. [48] It averages about 46 cm (18 in) in head-to-body length and 23–25 cm (9.1–9.8 in) in height, with about 30 cm (12 in) long tails. Males are larger than females. [49] Adult domestic cats typically weigh 4–5 kg (8.8–11.0 lb).
Signature. Charlotte of Mecklenburg-Strelitz (Sophia Charlotte; 19 May 1744 – 17 November 1818) was Queen of Great Britain and Ireland as the wife of King George III from their marriage on 8 September 1761 until her death in 1818. The Acts of Union 1800 unified Great Britain and Ireland into the United Kingdom of Great Britain and Ireland.
