Related Research Articles
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word laser is an anacronym that originated as an acronym for light amplification by stimulated emission of radiation. The first laser was built in 1960 by Theodore Maiman at Hughes Research Laboratories, based on theoretical work by Charles H. Townes and Arthur Leonard Schawlow.
Laser cooling includes several techniques where atoms, molecules, and small mechanical systems are cooled with laser light. The directed energy of lasers is often associated with heating materials, e.g. laser cutting, so it can be counterintuitive that laser cooling often results in sample temperatures approaching absolute zero. It is a routine step in many atomic physics experiments where the laser-cooled atoms are then subsequently manipulated and measured, or in technologies, such as atom-based quantum computing architectures. Laser cooling relies on the change in momentum when an object, such as an atom, absorbs and re-emits a photon. For example, if laser light illuminates a warm cloud of atoms from all directions and the laser's frequency is tuned below an atomic resonance, the atoms will be cooled. This common type of laser cooling relies on the Doppler effect where individual atoms will preferentially absorb laser light from the direction opposite to the atom's motion. The absorbed light is re-emitted by the atom in a random direction. After repeated emission and absorption of light the net effect on the cloud of atoms is that they will expand more slowly. The slower expansion reflects a decrease in the velocity distribution of the atoms, which corresponds to a lower temperature and therefore the atoms have been cooled. For an ensemble of particles, their thermodynamic temperature is proportional to the variance in their velocity, therefore the lower the distribution of velocities, the lower temperature of the particles.
In physics, coherence expresses the potential for two waves to interfere. Two monochromatic beams from a single source always interfere. Physical sources are not strictly monochromatic: they may be partly coherent. Beams from different sources are mutually incoherent.
Eli Yablonovitch is an American physicist and engineer who, along with Sajeev John, founded the field of photonic crystals in 1987. He and his team were the first to create a 3-dimensional structure that exhibited a full photonic bandgap, which has been named Yablonovite. In addition to pioneering photonic crystals, he was the first to recognize that a strained quantum-well laser has a significantly reduced threshold current compared to its unstrained counterpart. This is now employed in the majority of semiconductor lasers fabricated throughout the world. His seminal paper reporting inhibited spontaneous emission in photonic crystals is among the most highly cited papers in physics and engineering.
A quantum well is a potential well with only discrete energy values.
Quantum optics is a branch of atomic, molecular, and optical physics dealing with how individual quanta of light, known as photons, interact with atoms and molecules. It includes the study of the particle-like properties of photons. Photons have been used to test many of the counter-intuitive predictions of quantum mechanics, such as entanglement and teleportation, and are a useful resource for quantum information processing.
A quantum dot laser is a semiconductor laser that uses quantum dots as the active laser medium in its light emitting region. Due to the tight confinement of charge carriers in quantum dots, they exhibit an electronic structure similar to atoms. Lasers fabricated from such an active media exhibit device performance that is closer to gas lasers, and avoid some of the negative aspects of device performance associated with traditional semiconductor lasers based on bulk or quantum well active media. Improvements in modulation bandwidth, lasing threshold, relative intensity noise, linewidth enhancement factor and temperature insensitivity have all been observed. The quantum dot active region may also be engineered to operate at different wavelengths by varying dot size and composition. This allows quantum dot lasers to be fabricated to operate at wavelengths previously not possible using semiconductor laser technology. One challenge in the further advances with quantum dot lasers is the presence of multicarrier Auger processes which increases the nonradiative rate upon population inversion. Auger processes are intrinsic to the material but, in contrast to bulk semiconductors, they can be engineered to some degree in quantum dots at the cost of reducing the radiative rate. Another obstacle to the specific goal of electrically-pumped quantum dot lasing is the generally weak conductivity of quantum dot films.
A podcast is a program made available in digital format for download over the Internet. For example, an episodic series of digital audio files that users can download to a personal device to listen to at a time of their choosing. Podcasts are primarily an audio medium, but some distribute in video, either as their primary content or as a supplement to audio; popularised in recent years by video platform YouTube.
Thomas Andrew Merritt is an American technology journalist, writer, and broadcaster best known as the host of several podcasts. He is a former co-host of Tech News Today on the TWiT.tv Network, and was previously an executive editor for CNET and developer and co-host of the daily podcast Buzz Out Loud. As of March 2023, Merritt hosts Daily Tech News Show, Cordkillers and Sword and Laser, among other programs.
Federico Capasso is an applied physicist and is one of the inventors of the quantum cascade laser during his work at Bell Laboratories. He is currently on the faculty of Harvard University.
An atomic line filter (ALF) is a more effective optical band-pass filter used in the physical sciences for filtering electromagnetic radiation with precision, accuracy, and minimal signal strength loss. Atomic line filters work via the absorption or resonance lines of atomic vapors and so may also be designated an atomic resonance filter (ARF).
A quantum-well laser is a laser diode in which the active region of the device is so narrow that quantum confinement occurs. Laser diodes are formed in compound semiconductor materials that are able to emit light efficiently. The wavelength of the light emitted by a quantum-well laser is determined by the width of the active region rather than just the bandgap of the materials from which it is constructed. This means that much shorter wavelengths can be obtained from quantum-well lasers than from conventional laser diodes using a particular semiconductor material. The efficiency of a quantum-well laser is also greater than a conventional laser diode due to the stepwise form of its density of states function.
Walter Eric Spear FRSE PhD FRS FInstP was a German physicist noted for his pioneering work to help develop large area electronics and thin film displays. He was born in Frankfurt to a Jewish father and a Lutheran mother; by the time he finished his school examinations in 1938 life for Jews and people associated with Jews was becoming difficult. With the support of friends and relatives in Britain, the family were able to move to London, where he arrived in 1938 "with a small suitcase and a large cello".
Alfred ("Alf") Rodney Adams is a British physicist who invented the strained-layer quantum-well laser. Most modern homes will have several of these devices in their homes in all types of electronic equipment.
Troian Avery Bellisario is an American actress. A graduate of the University of Southern California, in 2010, she received her breakthrough role as Spencer Hastings in the Freeform drama series Pretty Little Liars (2010–2017), for which she received worldwide recognition and multiple awards and nominations.
Crosslight Software Inc. is an international company headquartered in greater Vancouver, British Columbia, Canada. Officially spun off from the National Research Council of Canada (NRC) in 1995, it provides Technology Computer Aided Design (TCAD) tools for semiconductor device and process simulations.
Eoin P. O’Reilly is an Irish physicist who, as of 2014, was chief scientific officer at the Tyndall Institute, and a professor of physics at University College Cork. In 2014 he was awarded the Rank Prize in Optoelectronics for his pioneering work on strained-layer laser structures.
Shun Lien Chuang was a Taiwanese-American electrical engineer, optical engineer, and physicist. He was a Fellow of the IEEE, OSA, APS and JSPS, and professor at the University of Illinois at Urbana-Champaign.
James J. Coleman is an electrical engineer who worked at Bell Labs, Rockwell International, and the University of Illinois, Urbana. He is best known for his work on semiconductor lasers, materials and devices including strained-layer indium gallium arsenide lasers and selective area epitaxy. Coleman is a Fellow of the IEEE and a member of the US National Academy of Engineering.
References
- 1 2 "A catalyst to our digital world: strained quantum well lasers—Full Case Study". SET squared. Universities of Bath, Bristol, Exetor, Southampton & Surrey. Retrieved 2 April 2015.
- ↑ "The Life Scientific: Alf Adams on Apple Podcasts". Apple Podcasts. Retrieved 2024-06-28.
 | This technology-related article is a stub. You can help Wikipedia by expanding it. |