Duarte and Piper introducedmultiple-prism near-grazing-incidence grating cavities which originally were disclosed ascopper-laser-pumped narrow-linewidth tunable laser oscillators.[2][3] Subsequently, he developed narrow-linewidth multiple-prism grating configurations for high-power CO2 laser oscillators[4] and solid-state tunable organic laser oscillators.[5][citation needed]
From the mid-1980s to early 1990s Duarte and scientists from theUSArmy Missile Command developedruggedizednarrow-linewidth laser oscillators tunable directly in the visible spectrum.[20][21] 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 tunablesolid state dye laser oscillators.[5] These dispersive oscillator architectures were then refined to yield single-longitudinal-mode emission limited only byHeisenberg's uncertainty principle.[22]
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.[23] In 2005, Duarte and colleagues were the first to demonstrate directional coherent emission from an electrically excitedorganic semiconductor.[24][25] These experiments utilized a tandemOLED within an integrated interferometric configuration.[24][25]
Duarte's work in this area began with the demonstration of narrow-linewidth laser emission usingcoumarin-tetramethyl dyes[26][27] which offer high conversion efficiency and wide tunability in the green region of the electromagnetic spectrum.[28]
Duarte and colleagues demonstrated the superposition of diffraction patterns overN-slit interferograms. This interferogram corresponds to the interferometric characterb (N = 3 slits) and exhibits a diffraction pattern superimposed on the right outer wing (see text).
In the late 1980s, he invented the digitalN-slit laser interferometer for applications in imaging andmicroscopy.[29] Concurrently, he appliedDirac's notation to describe quantum mechanically its interferometric and propagation characteristics.[30][31][32] 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.[32]
Further developments include very largeN-slit laser interferometers to generate and propagate interferometric characters forsecure free-space optical communications.[37][38]Interferometric characters is a term coined in 2002 to link interefometric signals to alphanumerical characters (see figure's legend).[37] These experiments provided the first observation of diffraction patterns superimposed over propagating interference signals, thus demonstrating non-destructive (or soft) interception of propagating interferograms.[38]
A spin-off of this research, with applications to the aviation industry, resulted from the discovery thatN-slit laser interferometers are very sensitive detectors ofclear air turbulence.[38][39]
Duarte provides a description of quantum optics, almost entirely via Dirac's notation, in his bookQuantum Optics for Engineers.[40] In this book he derives the probability amplitude for quantum entanglement,
which he calls thePryce-Ward probability amplitude, from anN-slit interferometric perspective. It is this that becomes the probability disclosed by Pryce and Ward.[41][42][43] Duarte also emphasizes a pragmatic non-interpretational approach to quantum mechanics.[40][41][44]
In 1983, Duarte traveled to the United States to assume a physics professorship at theUniversity of Alabama. In 1985 he joined the Imaging Research Laboratories, at theEastman Kodak Company, where he remained until 2006. While at Kodak he was chairman ofLasers '87 and subsequent conferences in this series.[47] Duarte has had a long association with the US Army Missile Command and theUS Army Aviation and Missile Command, where he has participated (with R. W. Conrad andT. S. Taylor[21]) indirected energy research.
In 1995, he received theEngineering Excellence Award for "the invention ofan electrooptic coherent interferometer for direct applications to imaging diagnostics of transparent surfaces, such as photographic film and film substrates.[49][50] and in 2016, he was awarded theDavid Richardson Medal for "seminal contributions to the physics and technology of multiple-prism arrays for narrow-linewidth tunable laser oscillators and laser pulse compression,"[51] from the Optical Society.
^Singh, Sunita; Dasgupta, K.; Kumar, S.; Manohar, K. G.; Nair, L. G.; Chatterjee, U. K. (1994-06-01). "High-power high-repetition-rate copper-vapor-pumped dye laser".Optical Engineering.33 (6). SPIE-Intl Soc Optical Eng:1894–1904.Bibcode:1994OptEn..33.1894S.doi:10.1117/12.168243.ISSN0091-3286.
^Sugiyama, Akira; Nakayama, T.; Kato, M.; Maruyama, Y.; Arisawa, T. (1996-04-01). "Characteristics of a pressure-tuned single-mode dye laser oscillator pumped by a copper vapor laser".Optical Engineering.35 (4). SPIE-Intl Soc Optical Eng:1093–1097.Bibcode:1996OptEn..35.1093S.doi:10.1117/1.600726.ISSN0091-3286.
^Singh, Nageshwar (2006-10-01). "Influence of optical inhomogeneity in the gain medium on the bandwidth of a high-repetition-rate dye laser pumped by copper vapor laser".Optical Engineering.45 (10). SPIE-Intl Soc Optical Eng: 104204.Bibcode:2006OptEn..45j4204S.doi:10.1117/1.2363168.ISSN0091-3286.
^Duarte, F. J.; Ehrlich, J. J.; Davenport, W. E.; Taylor, T. S. (1990-07-20). "Flashlamp pumped narrow-linewidth dispersive dye laser oscillators: very low amplified spontaneous emission levels and reduction of linewidth instabilities".Applied Optics.29 (21). The Optical Society:3176–9.Bibcode:1990ApOpt..29.3176D.doi:10.1364/ao.29.003176.ISSN0003-6935.PMID20567393.
^F. J. Duarte, Electro-optical interferometric microdensitometer system,US Patent 5255069 (1993).
^F. J. Duarte and D. J. Paine, Quantum mechanical description ofN-slit interference phenomena, inProceedings of the International Conference on Lasers '88, R. C. Sze and F. J. Duarte (Eds.) (STS, McLean, Va, 1989) pp. 42-47.
^F. J. Duarte, inHigh Power Dye Lasers (Springer-Verlag, Berlin,1991) Chapter 2.
^F. J. Duarte (2003).Tunable Laser Optics. New York: Elsevier Academic.ISBN978-0-12-222696-0.
^Duarte, F. J. (1997). "Interference, diffraction, and refraction, via Dirac's notation".American Journal of Physics.65 (7). American Association of Physics Teachers (AAPT):637–640.Bibcode:1997AmJPh..65..637D.doi:10.1119/1.18613.ISSN0002-9505.
^Duarte, F.J. (2005-11-17). "Multiple-prism dispersion equations for positive and negative refraction".Applied Physics B.82 (1). Springer Science and Business Media LLC:35–38.doi:10.1007/s00340-005-1996-x.ISSN0946-2171.S2CID120462686.
^Duarte, F. J. (1992-11-20). "Cavity dispersion equation Δλ ≈ Δθ(∂θ/∂λ)−1: a note on its origin".Applied Optics.31 (33). The Optical Society:6979–82.doi:10.1364/ao.31.006979.ISSN0003-6935.PMID20802556.
^B. Mansfield and M. Hutchinson,Liberality of Opportunity: A history of Macquarie University 1964-1989 (Hale and Iremonger, Sydney, 1992)
^F. J. Duarte,Proceedings of the International Conference on Lasers '87 (STS Press, Mc Lean, VA, 1988).
^"Francisco J. Duarte".Optica. September 26, 2018. RetrievedDecember 5, 2021.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.
^"OSA Announces Recipients of Several Awards".Physics Today.48 (11):104–105. 1995.Bibcode:1995PhT....48k.104..doi:10.1063/1.2808274.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."