@article{VollmerShaw2013, author = {Vollmer, Michael and Shaw, Joseph A.}, title = {Brilliant colours from a white snow cover}, series = {In: Physics Education 48 (2013) 3, 322-221}, journal = {In: Physics Education 48 (2013) 3, 322-221}, pages = {322 -- 331}, year = {2013}, language = {en} } @article{MangoldShawVollmer2013, author = {Mangold, Klaus and Shaw, Joseph A. and Vollmer, Michael}, title = {The physics of near-infrared photography}, series = {In: European journal of physics 34 (2013) 6, S51-S71}, journal = {In: European journal of physics 34 (2013) 6, S51-S71}, doi = {doi:10.1088/0143-0807/34/6/S51}, pages = {S51 -- S71}, year = {2013}, abstract = {The physics behind the sometimes strange effects and 'unnatural' appearance of near-infrared (NIR) photographs is discussed in terms of reflection, absorption and transmission of NIR radiation with the respective objects. Besides discussing how NIR cameras work, several visible and NIR photograph pairs are presented, which include vegetation, natural water, clouds, the sky, and humans. In addition, some physics-oriented experimental NIR images are presented which clearly demonstrate some of the basic physics behind some of these awesome sights.}, language = {en} } @article{NugentShawVollmer2015, author = {Nugent, Paul W. and Shaw, Joseph A. and Vollmer, Michael}, title = {Colors of thermal pools at Yellowstone National Park}, series = {Applied Optics Vol. 54 (2015 ) 4, pp. B128-B139}, journal = {Applied Optics Vol. 54 (2015 ) 4, pp. B128-B139}, doi = {10.1364/AO.54.00B128}, pages = {B128 -- B139}, year = {2015}, abstract = {Abstract The brilliant visible colors of various hot springs and pools in Yellowstone National Park are explained with a combination of scattering from the water and from microbial mats that coat the bottoms of these thermal features. A simple 1D radiative transfer model was used to simulate the colors recorded in visible photographs and the spectrum of light making up these colors. The model includes attenuation in water by absorption and molecular scattering as well as reflection characteristics of the microbial mats and surface reflection of the water. Pool geometries are simulated as simple rough cones scaled to have depths and widths that match published data. Thermal images are also used to record the spatial distribution of water skin temperature. The measurements and simulations confirm that colors observed from shallow-water features arise primarily from the spectral properties of the microbial mat, which is related to the water temperature, while colors observed from deeper water arise primarily from the wavelength-dependent absorption and scattering in the water.}, language = {en} } @article{ShawNugentVollmer2015, author = {Shaw, Joseph A. and Nugent, Paul W. and Vollmer, Michael}, title = {Infrared Moon imaging for remote sensing of atmospheric smoke layers}, series = {Applied Optics 54 (2015) 4, B64-B75}, journal = {Applied Optics 54 (2015) 4, B64-B75}, doi = {10.1364/AO.54.000B64}, pages = {B64 -- B75}, year = {2015}, abstract = {Abstract Simultaneous visible and long-wave infrared (IR) images of the Moon were used with a simple energy-balance model to study the spatial pattern of lunar surface temperatures. The thermal images were obtained with a radiometrically calibrated, compact, low-cost, commercial IR camera mounted on a small telescope. Differences between the predicted and measured maximum Moon temperatures were used to determine the infrared optical depth (OD), which represents the path-integrated extinction of an elevated layer of wildfire smoke in the atmosphere. The OD values retrieved from the IR Moon images were combined with simultaneous OD measurements from a ground-based, zenith-pointing lidar operating at a wavelength of 532 nm to determine an IR-to-visible OD ratio of 0.50±0.18 for moderately aged wildfire smoke aerosol. © 2014 Optical Society of America}, language = {en} } @article{VollmerShawNugent2015, author = {Vollmer, Michael and Shaw, Joseph A. and Nugent, Paul W.}, title = {Visible and invisible mirages: comparing inferior mirages in the visible and thermal infrared}, series = {Applied Optics 54 (2015) 4, B76-B84}, journal = {Applied Optics 54 (2015) 4, B76-B84}, doi = {10.1364/AO.54.000B76}, pages = {B76 -- B84}, year = {2015}, abstract = {Abstract Visible (VIS)-light and thermal infrared (IR) inferior mirages in the 8-14 μm waveband have been observed simultaneously for the takeoff and landing of various airplanes at distances of several kilometers. Similarities as well as differences between the VIS and IR mirages are discussed. © 2014 Optical Society of America}, language = {en} } @article{VollmerMoellmannShaw2015, author = {Vollmer, Michael and M{\"o}llmann, Klaus-Peter and Shaw, Joseph A.}, title = {The optics and physics of near infrared imaging}, series = {Proceedings of SPIE 9793, Education and Training in Optics and Photonics: ETOP 2015, 97930Z (October 8, 2015)}, journal = {Proceedings of SPIE 9793, Education and Training in Optics and Photonics: ETOP 2015, 97930Z (October 8, 2015)}, doi = {10.1117/12.2223094}, year = {2015}, abstract = {abstract A large part of photonics research and development, as well as commercial applications such as optical data transmission or infrared thermal imaging, occurs in the infrared spectral range between 0.8 μm and 15 μm. However, relatively little material is so far available for experimentally teaching the physics and optics of this spectral range. We report a respective new approach in the near infrared (NIR) range between 0.8 μm and 1.7 μm that allows visualization of a number of fascinating physics phenomena. First, we use the near-infrared sensitivity of silicon-based detectors in rather inexpensive video cameras and digital single-lens reflex cameras by removing the infrared-blocking filter and replacing it with a visible-radiation blocking filter. Second, we utilize modern NIR cameras based on InGaAs detectors. With both camera types we illustrate and explain a number of physics concepts that are especially suitable for curricula in optics and photonics. Examples include the strangely bright appearance of vegetation, contrast enhancement between clouds and sky, the initially surprising differences of optical material properties between the VIS and NIR range, the possibilities of visualizing buried hidden structures and texts, and recent medical applications to locate blood vessels below the skin. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.}, language = {en} } @article{ShawNugentVollmer2015, author = {Shaw, Joseph A. and Nugent, Paul and Vollmer, Michael}, title = {Colors of the Yellowstone thermal pools for teaching optics}, series = {Proceedings of SPIE 9793, Education and Training in Optics and Photonics: ETOP 2015, 97931S (October 8, 2015)}, journal = {Proceedings of SPIE 9793, Education and Training in Optics and Photonics: ETOP 2015, 97931S (October 8, 2015)}, doi = {10.1117/12.2223177}, year = {2015}, abstract = {abstract Nature provides many beautiful optical phenomena that can be used to teach optical principles. Here we describe an interdisciplinary education project based on a simple computer model of the colors observed in the famous thermal pools of Yellowstone National Park in the northwestern United States. The primary wavelength-dependent parameters that determine the widely varying pool colors are the reflectance of the rocks or the microbial mats growing on the rocks beneath the water (the microbial mat color depends on water temperature) and optical absorption and scattering in the water. This paper introduces a teaching module based on a one-dimensional computer model that starts with measured reflectance spectra of the microbial mats and modifies the spectra with depth-dependent absorption and scattering in the water. This module is designed to be incorporated into a graduate course on remote sensing systems, in a section covering the propagation of light through air and water, although it could be adapted to a general university optics course. The module presents the basic 1-D radiative transfer equation relevant to this problem, and allows them to build their own simple model. Students can then simulate the colors that would be observed for different variations of the microbial mat reflectance spectrum, skylight spectrum, and water depth. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.}, language = {en} } @article{MangoldShawVollmer2015, author = {Mangold, Klaus and Shaw, Joseph A. and Vollmer, Michael}, title = {Rotwein zu Wasser}, series = {Physik in unserer zeit 46 (2015) 1, 12-16}, journal = {Physik in unserer zeit 46 (2015) 1, 12-16}, doi = {10.1002/piuz.201401375}, pages = {12 -- 16}, year = {2015}, abstract = {Abstract Die Sensoren von Digitalkameras sind f{\"a}hig, Licht im Nahinfraroten (NIR) bis hin zu Wellenl{\"a}ngen von 1100 nm aufzunehmen. Infrarotfilter blockieren diesen f{\"u}r den Menschen nicht sichtbaren Spektralbereich, um irritierende Falschfarbeneffekte in den Aufnahmen zu verhindern. Diese Filter sind aber entfernbar, und derart umger{\"u}stete Kameras erschließen eine verbl{\"u}ffende Welt. Beim {\"U}bergang zum NIR {\"a}ndern sich die optischen Eigenschaften vieler Objekte. In Landschaftsaufnahmen werden Bl{\"a}tter zu den hellsten Objekten. Rotwein, Cola oder Kaffee werden scheinbar zu Wasser. Man kann zudem unter die Oberfl{\"a}che von Farben, Stoffen, Lacken und sogar der Haut schauen.}, language = {de} } @article{VollmerShawNugent2017, author = {Vollmer, Michael and Shaw, Joseph A. and Nugent, Paul W.}, title = {Heiße Physik im Yellowstone-Park: Wie Farben in Thermalquellen entstehen}, series = {Physik in unserer Zeit}, volume = {48}, journal = {Physik in unserer Zeit}, number = {1}, issn = {1521-3943 (online)}, doi = {10.1002/piuz.201601431}, pages = {37 -- 42}, year = {2017}, language = {de} } @inproceedings{VollmerShawNugentetal.2017, author = {Vollmer, Michael and Shaw, Joseph A. and Nugent, Paul W. and Harris, Wilson and Gillis, Kendra and Weiss, William and Carpenter, Logan and Carpenter, Amy and Scherrer, Bryan}, title = {Photonics in nature: Yellowstone National Park in IR}, series = {14th Conference on Education and Training in Optics and Photonics, ETOP 2017, 2017, Hangzhou, China}, booktitle = {14th Conference on Education and Training in Optics and Photonics, ETOP 2017, 2017, Hangzhou, China}, doi = {10.1117/12.2266677}, year = {2017}, language = {en} } @article{ShawVollmer2017, author = {Shaw, Joseph A. and Vollmer, Michael}, title = {Blue sun glints on water viewed through a polarizer}, series = {Applied Optics}, volume = {56}, journal = {Applied Optics}, number = {19}, issn = {1539-4522; 1540-8981 (Online)}, doi = {10.1364/AO.56.000G36}, pages = {G36 -- G41}, year = {2017}, language = {en} } @article{ShawNugentHarrisetal.2017, author = {Shaw, Joseph A. and Nugent, Paul W. and Harris, Wilson and Vollmer, Michael}, title = {Infrared Yellowstone}, series = {Optics and Photonics News}, volume = {28}, journal = {Optics and Photonics News}, number = {6}, issn = {1541-3721 (Online)}, doi = {10.1364/OPN.28.6.000036}, pages = {36 -- 43}, year = {2017}, language = {en} } @article{VollmerShaw2017, author = {Vollmer, Michael and Shaw, Joseph A.}, title = {Atmospheric optics in the near infrared}, series = {Applied Optics}, volume = {56}, journal = {Applied Optics}, number = {19}, issn = {1539-4522 (Online)}, doi = {10.1364/AO.56.00G145}, pages = {G145 -- G155}, year = {2017}, language = {en} } @article{VollmerShaw2022, author = {Vollmer, Michael and Shaw, Joseph A.}, title = {Seeing better in nature: contrast enhancement by near infrared imaging}, series = {European Journal of Physics}, volume = {43}, journal = {European Journal of Physics}, number = {3}, publisher = {Institute of Physics Publishing}, doi = {10.1088/1361-6404/ac578d}, year = {2022}, language = {en} } @inproceedings{ShawVollmer2017, author = {Shaw, Joseph A. and Vollmer, Michael}, title = {Blue sun reflected from water: optical lessons from observations of nature}, series = {14th Conference on Education and Training in Optics and Photonics, ETOP 2017, 2017, Hangzhou, China}, booktitle = {14th Conference on Education and Training in Optics and Photonics, ETOP 2017, 2017, Hangzhou, China}, doi = {10.1117/12.2270481}, year = {2017}, language = {en} } @article{VollmerShawNugentetal.2019, author = {Vollmer, Michael and Shaw, Joseph A. and Nugent, Paul and Harris, Wilson}, title = {Heiße Quellen im W{\"a}rmebild. Yellowstone-Park im Infraroten}, series = {Physik in unserer Zeit}, volume = {50}, journal = {Physik in unserer Zeit}, number = {5}, publisher = {Wiley-VCH}, doi = {10.1002/piuz.201901539}, pages = {244 -- 250}, year = {2019}, language = {de} } @inproceedings{VollmerShaw2019, author = {Vollmer, Michael and Shaw, Joseph A.}, title = {Near infrared photography of atmospheric optical phenomena}, series = {Fifteenth Conference on Education and Training in Optics and Photonics: ETOP 2019}, booktitle = {Fifteenth Conference on Education and Training in Optics and Photonics: ETOP 2019}, address = {Quebec City, Quebec, Canada}, doi = {10.1117/12.2523165}, pages = {111431P-1 -- 111431P-6}, year = {2019}, language = {en} } @inproceedings{VollmerShaw2019, author = {Vollmer, Michael and Shaw, Joseph A.}, title = {Extended visual range: an observation during a total solar eclipse}, series = {Fifteenth Conference on Education and Training in Optics and Photonics: ETOP 2019}, booktitle = {Fifteenth Conference on Education and Training in Optics and Photonics: ETOP 2019}, address = {Quebec City, Quebec, Canada}, doi = {10.1117/12.2523167}, pages = {111431Q-1 -- 111431Q-6}, year = {2019}, language = {en} } @article{VollmerShaw2018, author = {Vollmer, Michael and Shaw, Joseph A.}, title = {Extended visual range during solar eclipses}, series = {Applied Optics}, volume = {57}, journal = {Applied Optics}, number = {12}, doi = {10.1364/AO.57.003250}, pages = {3250 -- 3259}, year = {2018}, language = {en} }