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F. J. Duarte | |
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Born | c. 1954 |
Nationality | Chilean American |
Alma mater | Macquarie University |
Known for | Tunable lasers Narrow-linewidth dye lasers Multiple-prism dispersion theory N-slit interferometer N-slit interferometric equation |
Awards | Paul F. Forman Engineering Excellence Award (1995) David Richardson Medal (2016) |
Scientific career | |
Fields | Physics Optics |
Institutions | Macquarie University University of New South Wales University of Alabama Eastman Kodak Company State University of New York University of New Mexico Interferometric Optics |
Doctoral advisor | J. A. Piper |
Other academic advisors | J. C. Ward R. E. Aitchison |
Francisco Javier "Frank" Duarte (born c. 1954) is a laser physicist and author/editor of several books on tunable lasers.
His research on physical optics and laser development has won several awards, including an Engineering Excellence Award in 1995 for the invention of the N-slit laser interferometer.
Duarte and Piper introduced multiple-prism near-grazing-incidence grating cavities which originally were disclosed as copper-laser-pumped narrow-linewidth tunable laser oscillators. [1] [2] Subsequently, he developed narrow-linewidth multiple-prism grating configurations for high-power CO2 laser oscillators [3] and solid-state tunable organic laser oscillators. [4] [ citation needed ]
Duarte also conceived the multiple-prism dispersion theories for tunable narrow-linewidth laser oscillators, [5] and multiple-prism laser pulse compression, [6] [7] which are summarized in several of his books. [8] [9] [10] The introduction to this theory is the generalized multiple-prism dispersion equation [5]
His tunable narrow-linewidth laser oscillator configurations [2] [13] have been adopted by various research groups working on uranium atomic vapor laser isotope separation (AVLIS). [14] [15] [16] This work was supported by the Australian Atomic Energy Commission. [13] During the course of this research, Duarte writes that he did approach the then federal minister for energy, Sir John Carrick, to advocate for the introduction of an AVLIS facility in Australia. [17] In 2002, he participated in research that led to the isotope separation of lithium using narrow-linewidth tunable diode lasers. [18]
From the mid-1980s to early 1990s Duarte and scientists from the US Army Missile Command developed ruggedized narrow-linewidth laser oscillators tunable directly in the visible spectrum. [19] [20] This constituted the first disclosure, in the open literature, of a tunable narrow-linewidth laser tested on a rugged terrain. This research led to experimentation with polymer gain media and in 1994 Duarte reported on the first narrow-linewidth tunable solid state dye laser oscillators. [4] These dispersive oscillator architectures were then refined to yield single-longitudinal-mode emission limited only by Heisenberg's uncertainty principle. [21]
Joint research, with R. O. James, on solid-state organic-inorganic materials, led to the discovery of polymer-nanoparticle gain media and to the emission of tunable low-divergence homogeneous laser beams from this class of media. [22] In 2005, Duarte and colleagues were the first to demonstrate directional coherent emission from an electrically excited organic semiconductor. [23] [24] These experiments utilized a tandem OLED within an integrated interferometric configuration. [23] [24]
Duarte's work in this area began with the demonstration of narrow-linewidth laser emission using coumarin-tetramethyl dyes [25] [26] which offer high conversion efficiency and wide tunability in the green region of the electromagnetic spectrum. [27]
In the late 1980s, he invented the digital N-slit laser interferometer for applications in imaging and microscopy. [28] Concurrently, he applied Dirac’s notation to describe quantum mechanically its interferometric and propagation characteristics. [29] [30] [31] A further innovation in this interferometer was the use of extremely elongated Gaussian beams, width to height ratios of up to 2000:1, for sample illumination. [31]
This research also led to the generalized N-slit interferometric equation that was then applied to describe classical optics phenomena such as interference, diffraction, refraction, and reflection, in a generalized and unified quantum approach [32] [33] that includes positive and negative refraction. [34] He also derived the cavity linewidth equation, for dispersive laser oscillators, using quantum mechanical principles. [35]
Further developments include very large N-slit laser interferometers to generate and propagate interferometric characters for secure free-space optical communications. [36] [37] Interferometric characters is a term coined in 2002 to link interefometric signals to alphanumerical characters (see figure's legend). [36] These experiments provided the first observation of diffraction patterns superimposed over propagating interference signals, thus demonstrating non-destructive (or soft) interception of propagating interferograms. [37]
A spin-off of this research, with applications to the aviation industry, resulted from the discovery that N-slit laser interferometers are very sensitive detectors of clear air turbulence. [37] [38]
Duarte provides a description of quantum optics, almost entirely via Dirac's notation, in his book Quantum Optics for Engineers. [39] In this book he derives the probability amplitude for quantum entanglement,
which he calls the Pryce-Ward probability amplitude, from an N-slit interferometric perspective. It is this that becomes the probability disclosed by Pryce and Ward. [40] [41] [42] Duarte also emphasizes a pragmatic non-interpretational approach to quantum mechanics. [39] [40] [43]
At Macquarie University, Duarte studied quantum physics under John Clive Ward and semiconductor physics under Ronald Ernest Aitchison. His PhD research was on laser physics and his supervisor was James A. Piper.
In the area of university politics, he established and led the Macquarie science reform movement, [44] [45] that transformed the degree structure of the university. Macquarie's science reform, was widely supported by local scientists including physicists R. E. Aitchison, R. E. B. Makinson, A. W. Pryor, and J. C. Ward. In 1980, Duarte was elected as one of the Macquarie representatives to the Australian Union of Students from where he was expelled, and then reinstated, for "running over the tables."[ citation needed ]
Following completion of his PhD work, Duarte did post doctoral research, with B. J. Orr at the University of New South Wales, and then back at Macquarie University.
In 1983, Duarte traveled to the United States to assume a physics professorship at the University of Alabama. In 1985 he joined the Imaging Research Laboratories, at the Eastman Kodak Company, where he remained until 2006. While at Kodak he was chairman of Lasers '87 and subsequent conferences in this series. [46] Duarte has had a long association with the US Army Missile Command and the US Army Aviation and Missile Command, where he has participated (with R. W. Conrad and T. S. Taylor [20] ) in directed energy research.
He was elected Fellow of the Australian Institute of Physics in 1987) and a Fellow of the Optical Society of America in 1993. [47]
In 1995, he received the Engineering Excellence Award for "the invention of an electrooptic coherent interferometer for direct applications to imaging diagnostics of transparent surfaces, such as photographic film and film substrates. [48] [49] and in 2016, he was awarded the David Richardson Medal for "seminal contributions to the physics and technology of multiple-prism arrays for narrow-linewidth tunable laser oscillators and laser pulse compression," [50] from the Optical Society.
Duarte was born in Santiago, Chile, and traveled to Sydney, Australia, as a teenager. There, he lived first in Strathfield and then in the northern small town of Cowan. In the United States he resided for a brief period in Tuscaloosa, Alabama, and then moved to Western New York. [ citation needed ]
Coherence expresses the potential for two waves to interfere. Two monochromatic beams from a single source always interfere. Wave sources are not strictly monochromatic: they may be partly coherent. Beams from different sources are mutually incoherent.
A dye laser is a laser that uses an organic dye as the lasing medium, usually as a liquid solution. Compared to gases and most solid state lasing media, a dye can usually be used for a much wider range of wavelengths, often spanning 50 to 100 nanometers or more. The wide bandwidth makes them particularly suitable for tunable lasers and pulsed lasers. The dye rhodamine 6G, for example, can be tuned from 635 nm (orangish-red) to 560 nm (greenish-yellow), and produce pulses as short as 16 femtoseconds. Moreover, the dye can be replaced by another type in order to generate an even broader range of wavelengths with the same laser, from the near-infrared to the near-ultraviolet, although this usually requires replacing other optical components in the laser as well, such as dielectric mirrors or pump lasers.
Tunable diode laser absorption spectroscopy is a technique for measuring the concentration of certain species such as methane, water vapor and many more, in a gaseous mixture using tunable diode lasers and laser absorption spectrometry. The advantage of TDLAS over other techniques for concentration measurement is its ability to achieve very low detection limits. Apart from concentration, it is also possible to determine the temperature, pressure, velocity and mass flux of the gas under observation. TDLAS is by far the most common laser based absorption technique for quantitative assessments of species in gas phase.
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.
An excimer laser, sometimes more correctly called an exciplex laser, is a form of ultraviolet laser which is commonly used in the production of microelectronic devices, semiconductor based integrated circuits or "chips", eye surgery, and micromachining.
A tunable laser is a laser whose wavelength of operation can be altered in a controlled manner. While all laser gain media allow small shifts in output wavelength, only a few types of lasers allow continuous tuning over a significant wavelength range.
An optical parametric oscillator (OPO) is a parametric oscillator that oscillates at optical frequencies. It converts an input laser wave with frequency into two output waves of lower frequency by means of second-order nonlinear optical interaction. The sum of the output waves' frequencies is equal to the input wave frequency: . For historical reasons, the two output waves are called "signal" and "idler", where the output wave with higher frequency is the "signal". A special case is the degenerate OPO, when the output frequency is one-half the pump frequency, , which can result in half-harmonic generation when signal and idler have the same polarization.
Theodor Wolfgang Hänsch is a German physicist. He received one-fourth of the 2005 Nobel Prize in Physics for "contributions to the development of laser-based precision spectroscopy, including the optical frequency comb technique", sharing the prize with John L. Hall and Roy J. Glauber.
Amplified spontaneous emission (ASE) or superluminescence is light, produced by spontaneous emission, that has been optically amplified by the process of stimulated emission in a gain medium. It is inherent in the field of random lasers.
Beam expanders are optical devices that take a collimated beam of light and expand its width.
The first description of multiple-prism arrays, and multiple-prism dispersion, was given by Newton in his book Opticks. Prism pair expanders were introduced by Brewster in 1813. A modern mathematical description of the single-prism dispersion was given by Born and Wolf in 1959. The generalized multiple-prism dispersion theory was introduced by Duarte and Piper in 1982.
The N-slit interferometer is an extension of the double-slit interferometer also known as Young's double-slit interferometer. One of the first known uses of N-slit arrays in optics was illustrated by Newton. In the first part of the twentieth century, Michelson described various cases of N-slit diffraction.
Fritz Peter Schäfer was a German physicist, born in Hersfeld, Hesse-Nassau. He is the co-inventor of the organic dye laser. His book, Dye Lasers, is considered a classic in the field of tunable lasers. In this book the chapter written by Schäfer gives an ample and insightful exposition on organic laser dye molecules in addition to a description on the physics of telescopic, and multiple-prism, tunable narrow-linewidth laser oscillators.
Quantum mechanics was first applied to optics, and interference in particular, by Paul Dirac. Richard Feynman, in his Lectures on Physics, uses Dirac's notation to describe thought experiments on double-slit interference of electrons. Feynman's approach was extended to N-slit interferometers for either single-photon illumination, or narrow-linewidth laser illumination, that is, illumination by indistinguishable photons, by Frank Duarte. The N-slit interferometer was first applied in the generation and measurement of complex interference patterns.
A solid-state dye laser (SSDL) is a solid-state lasers in which the gain medium is a laser dye-doped organic matrix such as poly(methyl methacrylate) (PMMA), rather than a liquid solution of the dye. These lasers are also referred to as solid-state organic lasers and solid-state dye-doped polymer lasers.
Gas in scattering media absorption spectroscopy (GASMAS) is an optical technique for sensing and analysis of gas located within porous and highly scattering solids, e.g. powders, ceramics, wood, fruit, translucent packages, pharmaceutical tablets, foams, human paranasal sinuses etc. It was introduced in 2001 by Prof. Sune Svanberg and co-workers at Lund University (Sweden). The technique is related to conventional high-resolution laser spectroscopy for sensing and spectroscopy of gas, but the fact that the gas here is "hidden" inside solid materials give rise to important differences.
Multiple-prism grating laser oscillators, or MPG laser oscillators, use multiple-prism beam expansion to illuminate a diffraction grating mounted either in Littrow configuration or grazing-incidence configuration. Originally, these narrow-linewidth tunable dispersive oscillators were introduced as multiple-prism Littrow (MPL) grating oscillators, or hybrid multiple-prism near-grazing-incidence (HMPGI) grating cavities, in organic dye lasers. However, these designs were quickly adopted for other types of lasers such as gas lasers, diode lasers, and more recently fiber lasers.
Laser linewidth is the spectral linewidth of a laser beam.
James A. (Jim) Piper was a New Zealand/Australian physicist, Deputy Vice-Chancellor (Research) and Professor of Physics at Macquarie University.
An organic laser is a laser which uses an organic material as the gain medium. The first organic laser was the liquid dye laser. These lasers use laser dye solutions as their gain media.
Duarte was elected Fellow of the Australian Institute of Physics in 1987. In 1981 he joined the OSA, following publication of one of his papers in Applied Optics, and was elected Fellow in 1993. He has received the Engineering Excellence Award (1995), 'for the invention of the N-slit laser interferometer,' and the David Richardson Medal (2016) 'for seminal contributions to the physics and technology of multiple-prism arrays for narrow-linewidth tunable laser oscillators and laser pulse compression' from Optica.
There are six recipients of Engineering Excellence Awards from OSA: Francisco J. Duarte, John D. Gonglewski, Gary Guenther, Melvyn H. Kreitzer, Frank Luecke and David G. Voelz. Duarte, a business leader at Eastman Kodak in Rochester, New York, is recognized for "the invention of an electrooptic coherent interferometer for direct applications to imaging diagnostics of transparent surfaces, such as photographic film and film substrates."