| 1. |
- Brydegaard, Mikkel, et al.
(författare)
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Broad-band multispectral microscope for imaging transmission spectroscopy employing an array of light-emitting diodes
- 2009
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Ingår i: American Journal of Physics. - : American Association of Physics Teachers (AAPT). - 0002-9505 .- 1943-2909. ; 77:2, s. 104-110
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Tidskriftsartikel (refereegranskat)abstract
- Optical spectral analysis and multispectral imaging provide powerful means for characterizing samples in a wide variety of applications and on many spatial scales. We present a simple implementation of these techniques in the context of microscopy. A modified commercial microscope equipped with a CMOS imaging detector, combined with an array of light emitting diodes with emission ranging from ultraviolet to near-infrared wavelengths, is described, and examples of information enhancement using multivariate analysis are presented.
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| 2. |
- Brydegaard, Mikkel, et al.
(författare)
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Insect monitoring with fluorescence lidar techniques: feasibility study.
- 2009
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Ingår i: Applied Optics. - 2155-3165. ; 48:30, s. 5668-5677
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Tidskriftsartikel (refereegranskat)abstract
- We investigate the possibilities of light detection and ranging (lidar) techniques to study migration of the damselfly species Calopteryx splendens and C. virgo. Laboratory and testing-range measurements at a distance of 60 m were performed using dried, mounted damselfly specimens. Laboratory measurements, including color photography in polarized light and spectroscopy of reflectance and induced fluorescence, reveal that damselflies exhibit reflectance and fluorescence properties that are closely tied to the generation of structural color. Lidar studies on C. splendens of both genders show that gender can be remotely determined, especially for specimens that were marked with Coumarin 102 and Rhodamine 6G dyes. The results obtained in this study will be useful for future field experiments, and provide guidelines for studying damselflies in their natural habitat using lidar to survey the air above the river surface. The findings will be applicable for many other insect species and should, therefore, bring new insights into migration and movement patterns of insects in general.
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| 3. |
- Guan, Zuguang, et al.
(författare)
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Assessment of photon migration in scattering media using heterodyning techniques with a frequency modulated diode laser.
- 2009
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Ingår i: Optics Express. - 1094-4087. ; 17:18, s. 16291-16299
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Tidskriftsartikel (refereegranskat)abstract
- A novel technique for studying photon propagation in scattering media is proposed and demonstrated, as is believed, for the first time. Photons propagating through the medium, from a frequency-ramped single-mode diode laser, meet a reference beam from the same source, at a common detector, and beat frequencies corresponding to various temporal delays are observed by heterodyne techniques. Fourier transformation directly yields the temporal dispersion curve. Proof-of-principle experiments on polystyrene foam and a tissue phantom suggest, that the new method, when fully developed, may favorably compete with the more complex time-correlated single-photon counting (TCSPC) and the phase-shift methods, now much employed.
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| 4. |
- Guan, Zuguang, et al.
(författare)
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LIDAR technique for Remote Gas Analysis in Solid Scattering Media
- 2009
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Ingår i: Asia Optical Fiber Communication & Optoelectronic Exposition & Conference, 2008. AOE 2008.. - 9781557528636
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Konferensbidrag (refereegranskat)abstract
- LIDAR techniques are used to measure gases in solid scattering media remotely, by analyzing the differential absorption observed in the multiple scattering light. The gas exchange (O-2/N-2) in polystyrene foam is monitored. (C)2008 Optical Society of America
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| 5. |
- Lewander, Märta, et al.
(författare)
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Clinical system for non-invasive in situ monitoring of gases in the human paranasal sinuses
- 2009
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Ingår i: Optics Express. - 1094-4087. ; 17:13, s. 10849-10863
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Tidskriftsartikel (refereegranskat)abstract
- We present a portable system for non-invasive, simultaneous sensing of molecular oxygen (O-2) and water vapor (H2O) in the human paranasal cavities. The system is based on high-resolution tunable diode laser spectroscopy (TDLAS) and digital wavelength modulation spectroscopy (dWMS). Since optical interference and non-ideal tuning of the diode lasers render signal processing complex, we focus on Fourier analysis of dWMS signals and procedures for removal of background signals. Clinical data are presented, and exhibit a significant improvement in signal-to-noise with respect to earlier work. The in situ detection limit, in terms of absorption fraction, is about 5 x 10(-5) for oxygen and 5 x 10(-4) for water vapor, but varies between patients due to differences in light attenuation. In addition, we discuss the use of water vapor as a reference in quantification of in situ oxygen concentration in detail. In particular, light propagation aspects are investigated by employing photon time-of-flight spectroscopy. (C) 2009 Optical Society of America
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| 6. |
- Lewander, Märta, et al.
(författare)
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Gas Analysis in Food Packages Using Tunable Diode Laser Spectroscopy
- 2009
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Ingår i: Asia Optical Fiber Communication & Optoelectronic Exposition & Conference, 2008. AOE 2008.. - 9781557528636
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Konferensbidrag (refereegranskat)abstract
- Gas inside packed food is monitored by a technique named GASMAS, GAs in Scattering Media Absorption Spectroscopy. The sharp gas absorption line in contrast to the broadband bulk absorption enables gas detection in situ. (C)2008 Optical Society of America
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