Patrick Gill | |
|---|---|
 Gill in 2016 | |
| Awards | |
| Website | www |
| Scientific career | |
| Thesis | Charge Transfer as a Laser Excitation Mechanism (1975) |
| Doctoral advisor | Colin Webb |
Patrick Gill is a British physicist who is a Senior NPL Fellow in Time & Frequency at the National Physical Laboratory (NPL) in the UK. [1] [2]
Gill was educated at the University of Sussex and the University of Oxford where he was awarded a Doctor of Philosophy degree in 1975 for research on Charge Transfer as a Laser Excitation Mechanism. [3]
Gill's research is concerned with laser frequency stabilisation techniques for very high resolution spectroscopy, and the development of leading-edge optical atomic clocks that look to form the basis of a future redefinition of the SI base unit second. [4] These include optical clocks based on laser-cooled single ions confined in radiofrequency traps and neutral atoms held in optical lattices, and which now reach uncertainties below that of the caesium fountain primary frequency standard. [5] [6]
Additionally, he has developed a range of stable lasers and optical metrology instrumentation with application to high technology sectors such as precision engineering and manufacture, space science, satellite navigation, Earth observation, defence and security and optical telecommunications. [7] [8] [9] [10]
Gill is a Fellow of the Institute of Physics (FInstP) and was awarded their Young Medal and Prize in 2008 for world-leading contributions to optical frequency metrology. He also received the I. I. Rabi Award in 2007 from the IEEE International Frequency Control Symposium for contributions to time and frequency metrology and the realisation of single ion optical frequency standards. More recently, his group received the Royal Institute of Navigation's Duke of Edinburgh Award in 2014 for long term atomic clock development. [5] Patrick is a visiting professor at Imperial College London and the University of Oxford. He was awarded an MBE for services to Science in The Queen's 2015 New Year Honours. [11] Gill was elected a Fellow of the Royal Society (FRS) in 2016. [5]
The second is a unit of time, historically defined as 1⁄86400 of a day – this factor derived from the division of the day first into 24 hours, then to 60 minutes and finally to 60 seconds each.
Titanium-sapphire lasers (also known as Ti:sapphire lasers, Ti:Al2O3 lasers or Ti:sapphs) are tunable lasers which emit red and near-infrared light in the range from 650 to 1100 nanometers. These lasers are mainly used in scientific research because of their tunability and their ability to generate ultrashort pulses thanks to its broad light emission spectrum. Lasers based on Ti:sapphire were first constructed and invented in June 1982 by Peter Moulton at the MIT Lincoln Laboratory.
Thorium (90Th) has seven naturally occurring isotopes but none are stable. One isotope, 232Th, is relatively stable, with a half-life of 1.405×1010 years, considerably longer than the age of the Earth, and even slightly longer than the generally accepted age of the universe. This isotope makes up nearly all natural thorium, so thorium was considered to be mononuclidic. However, in 2013, IUPAC reclassified thorium as binuclidic, due to large amounts of 230Th in deep seawater. Thorium has a characteristic terrestrial isotopic composition and thus a standard atomic weight can be given.
Doppler cooling is a mechanism that can be used to trap and slow the motion of atoms to cool a substance. The term is sometimes used synonymously with laser cooling, though laser cooling includes other techniques.
A frequency comb or spectral comb is a spectrum made of discrete and regularly spaced spectral lines. In optics, a frequency comb can be generated by certain laser sources.
In condensed matter physics, an ultracold atom is an atom with a temperature near absolute zero. At such temperatures, an atom's quantum-mechanical properties become important.
The nitrogen-vacancy center is one of numerous photoluminescent point defects in diamond. Its most explored and useful properties include its spin-dependent photoluminescence, and its relatively long (millisecond) spin coherence at room temperature. The NV center energy levels are modified by magnetic fields, electric fields, temperature, and strain, which allow it to serve as a sensor of a variety of physical phenomena. Its atomic size and spin properties can form the basis for useful quantum sensors. It has also been explored for applications in quantum computing, quantum simulation, and spintronics.
Within quantum technology, a quantum sensor utilizes properties of quantum mechanics, such as quantum entanglement, quantum interference, and quantum state squeezing, which have optimized precision and beat current limits in sensor technology. The field of quantum sensing deals with the design and engineering of quantum sources and quantum measurements that are able to beat the performance of any classical strategy in a number of technological applications. This can be done with photonic systems or solid state systems.
A nuclear clock or nuclear optical clock is a atomic clock being developed that will use the energy of a nuclear isomeric transition as its reference frequency, instead of the atomic electron transition energy used by conventional atomic clocks. Such a clock is expected to be more accurate than the best current atomic clocks by a factor of about 10, with an achievable accuracy approaching the 10−19 level.
David Jeffery Wineland is an American physicist at the Physical Measurement Laboratory of the National Institute of Standards and Technology (NIST). His most notable contributions include the laser cooling of trapped ions and the use of ions for quantum-computing operations. He received the 2012 Nobel Prize in Physics, jointly with Serge Haroche, for "ground-breaking experimental methods that enable measuring and manipulation of individual quantum systems."
Photoelectrochemical processes are processes in photoelectrochemistry; they usually involve transforming light into other forms of energy. These processes apply to photochemistry, optically pumped lasers, sensitized solar cells, luminescence, and photochromism.
An atomic clock is a clock that measures time by monitoring the resonant frequency of atoms. It is based on atoms having different energy levels. Electron states in an atom are associated with different energy levels, and in transitions between such states they interact with a very specific frequency of electromagnetic radiation. This phenomenon serves as the basis for the International System of Units' (SI) definition of a second:
The second, symbol s, is the SI unit of time. It is defined by taking the fixed numerical value of the caesium frequency, , the unperturbed ground-state hyperfine transition frequency of the caesium-133 atom, to be 9192631770 when expressed in the unit Hz, which is equal to s−1.
A quantum clock is a type of atomic clock with laser cooled single ions confined together in an electromagnetic ion trap. Developed in 2010 by physicists at the U.S. National Institute of Standards and Technology, the clock was 37 times more precise than the then-existing international standard. The quantum logic clock is based on an Al spectroscopy ion with a logic atom.
Peter E. Toschek was a German experimental physicist who researched nuclear physics, quantum optics, and laser physics. He is known as a pioneer of laser spectroscopy and for the first demonstration of single trapped atoms (ions). He was a professor at Hamburg University.
The magic wavelength is the wavelength of an optical lattice where the polarizabilities of two atomic clock states have the same value, such that the AC Stark shift caused by the laser intensity fluctuation has no effect on the transition frequency between the two clock states.
Debabrata Goswami FInstP FRSC, is an Indian chemist and the Prof. S. Sampath Chair Professor of Chemistry, at the Indian Institute of Technology Kanpur. He is also a professor of The Department of Chemistry and The Center for Lasers & Photonics at the same Institute. Goswami is an associate editor of the open-access journal Science Advances. He is also an Academic Editor for PLOS One and PeerJ Chemistry. He has contributed to the theory of Quantum Computing as well as nonlinear optical spectroscopy. His work is documented in more than 200 research publications. He is an elected Fellow of the Royal Society of Chemistry, Fellow of the Institute of Physics, the SPIE, and The Optical Society. He is also a Senior Member of the IEEE, has been awarded a Swarnajayanti Fellowship for Chemical Sciences, and has held a Wellcome Trust Senior Research Fellowship. He is the third Indian to be awarded the International Commission for Optics Galileo Galilei Medal for excellence in optics.
Helen Sarah Margolis is a British physicist who is a Senior Fellow and Head of Science for Time and Frequency at the National Physical Laboratory. Her research considers the use of optical frequency metrology using femtosecond combs.
An optical clock is a clock that uses light to track time. It differs from an atomic clock in that it uses visible light, rather than microwaves. Several chemical elements have been studied for possible use in optical clocks. These include aluminum, mercury, strontium, indium, magnesium, calcium, ytterbium, and thorium. The concept of an optical clock originated with John L. Hall and Theodor W. Hansch, who together won the 2005 Nobel Prize in Physics.
The Dick effect is an important limitation to frequency stability for modern atomic clocks such as atomic fountains and optical lattice clocks. It is an aliasing effect: High frequency noise in a required local oscillator (LO) is aliased (heterodyned) to near zero frequency by a periodic interrogation process that locks the frequency of the LO to that of the atoms. The noise mimics and adds to the clock's inherent statistical instability, which is determined by the number of atoms or photons available. In so doing, the effect degrades the stability of the atomic clock and places new and stringent demands on LO performance.
Tara Michele Fortier is a Canadian physicist and Project Leader in the Time and Frequency Division at National Institute of Standards and Technology. Her research considers precision optical and microwave metrology. She was elected Fellow of the American Physical Society in 2022 and awarded the SPIE Harold E. Edgerton Award in High-Speed Optics in 2023.
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