Forschung

Die Arbeitsgruppe um Robert Huber forscht in den Bereichen der optischen Kohärenztomographie (OCT), der nichtlinearen Bildgebung und der Laserphysik. Hierbei wird vor allem an neuartigen Pikosekundenlaser und an Fourier domain modengekoppelten (FDML) Lasern gearbeitet. Dieses Laserkonzept wurde von Robert Huber entwickelt und erlaubt, besonders schnell durchstimmbare Laserlichtquellen zu realisieren. Die Forschungsschwerpunkte liegen hier in der technologischen Weiterentwicklung, dem Verständnis der physikalischen Vorgänge und auch in der Implementierung von FDML Lasern für OCT. Neben der OCT werden FDML Laser auch für die nichtlineare Bildgebung und Spektroskopie verwendet.

Ein weiterer Schwerpunkt liegt in der optischen Kohärenztomographie mit durchstimmbaren Lichtquellen (swept source OCT, SS-OCT). Hier werden unter anderem die selbst entwickelten FDML Laser für die ultraschnelle Bildgebung eingesetzt, um Schnittbilder von biologischen Gewebe wie Haut oder Auge zu erzeugen. Aufgrund der hohen Durchstimmrate sind Anwendungen wie die VR-OCT, die in einer virtuellen Umgebung ganze Volumina mit Video-Wiederholraten in Echtzeit darstellt, möglich.

Mit der nichtlinearen optischen Bildgebung verfolgt die Arbeitsgruppe weitere Bildgebungsverfahren. Die Forschungsgebiete liegen in der zeitcodierten (TICO) Ramanspektroskopie und -mikroskopie, der Zweiphotonen-Fluoreszenzmikroskopie (TPEF) und der Zweiphotonen-Einzelpuls-Fluoreszenzlebenszeitbildgebung (SP-FLIM). Für diese Verfahren kommen neuartige Pikosekunden zum Einsatz die ebenfalls in der Arbeitsgruppe erforscht und entwickelt werden.

Unsere Forschungsschwerpunkte:

Publikationen

2016

Robert Huber, Lars Dworak, Jacques E. Moser, Michael Grätzel, and Josef Wachtveitl,
Beyond Vibrationally Mediated Electron Transfer: Coherent Phenomena Induced by Ultrafast Charge Separation, The Journal of Physical Chemistry C , vol. 120, no. 16, pp. 8534-8539, 04 2016.
DOI:10.1021/acs.jpcc.6b02012
Bibtex: BibTeX
@article{doi:10.1021/acs.jpcc.6b02012,
author = {Huber, Robert and Dworak, Lars and Moser, Jacques E. and Grätzel, Michael and Wachtveitl, Josef},
title = {Beyond Vibrationally Mediated Electron Transfer: Coherent Phenomena Induced by Ultrafast Charge Separation},
journal = {The Journal of Physical Chemistry C},
volume = {120},
number = {16},
pages = {8534-8539},
year = {2016},
doi = {10.1021/acs.jpcc.6b02012},

URL = { 
        https://doi.org/10.1021/acs.jpcc.6b02012
    
},
eprint = { 
        https://doi.org/10.1021/acs.jpcc.6b02012
    
}
,
    abstract = { Wave packet propagation succeeding electron transfer (ET) from alizarin dye molecules into the nanocrystalline TiO2 semiconductor has been studied by ultrafast transient absorption spectroscopy. Because of the ultrafast time scale of the ET reaction of about 6 fs, the system shows substantial differences to molecular ET systems. We show that the ET process is not mediated by molecular vibrations, and therefore classical ET theories lose their applicability. Here the ET reaction itself prepares a vibrational wave packet and not the electromagnetic excitation by the laser pulse. Furthermore, the generation of phonons during polaron formation in the TiO2 lattice is observed in real time for this system. The presented investigations enable an unambiguous assignment of the involved photoinduced mechanisms and can contribute to a corresponding extension of molecular ET theories to ultrafast ET systems like alizarin/TiO2. }
}
Jan Philip Kolb, Thomas Klein, Matthias Eibl, Tom Pfeiffer, Wolfgang Wieser, and Robert Huber,
Megahertz FDML laser with up to 143nm sweep range for ultrahigh resolution OCT at 1050nm, in Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XX , Joseph A. Izatt and James G. Fujimoto and Valery V. Tuchin, Eds. SPIE, 2016. pp. 969703.
DOI:10.1117/12.2214758
Bibtex: BibTeX
@inproceedings{10.1117/12.2214758,
author = {Jan Philip Kolb and Thomas Klein and Matthias Eibl and Tom Pfeiffer and Wolfgang Wieser and Robert Huber},
title = {{Megahertz FDML laser with up to 143nm sweep range for ultrahigh resolution OCT at 1050nm}},
volume = {9697},
booktitle = {Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XX},
editor = {Joseph A. Izatt and James G. Fujimoto and Valery V. Tuchin},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {969703},
abstract = {We present a new design of a Fourier Domain Mode Locked laser (FDML laser), which provides a new record in sweep
range at ~1μm center wavelength: At the fundamental sweep rate of 2x417 kHz we reach 143nm bandwidth and 120nm
with 4x buffering at 1.67MHz sweep rate. The latter configuration of our system is characterized: The FWHM of the
point spread function (PSF) of a mirror is 5.6μm (in tissue). Human in vivo retinal imaging is performed with the MHz
laser showing more details in vascular structures. Here we could measure an axial resolution of 6.0μm by determining
the FWHM of specular reflex in the image. Additionally, challenges related to such a high sweep bandwidth such as
water absorption are investigated.},
keywords = {Optical coherence tomography, OCT, tunable laser, Fourier domain mode locking, FDML, MHz OCT},
year = {2016},
doi = {10.1117/12.2214758},
URL = {https://doi.org/10.1117/12.2214758}
}
Tianshi Wang, Tom Pfeiffer, Evelyn Regar, Wolfgang Wieser, Heleen van Beusekom, Charles T. Lancee, Geert Springeling, Ilona Krabbendam-Peters, Antonius F. W. van der Steen, Robert Huber, and Gijs van Soest,
Heartbeat OCT and Motion-Free 3D In Vivo Coronary Artery Microscopy, JACC: Cardiovascular Imaging , vol. 9, no. 5, pp. 622-623, 2016.
DOI:10.1016/j.jcmg.2015.08.010
Bibtex: BibTeX
@article{WANG2016622,
title = {Heartbeat OCT and Motion-Free 3D In Vivo Coronary Artery Microscopy},
journal = {JACC: Cardiovascular Imaging},
volume = {9},
number = {5},
pages = {622-623},
year = {2016},
issn = {1936-878X},
doi = {https://doi.org/10.1016/j.jcmg.2015.08.010},
url = {https://www.sciencedirect.com/science/article/pii/S1936878X15006713},
author = {Tianshi Wang and Tom Pfeiffer and Evelyn Regar and Wolfgang Wieser and Heleen {van Beusekom} and Charles T. Lancee and Geert Springeling and Ilona Krabbendam-Peters and Antonius F.W. {van der Steen} and Robert Huber and Gijs {van Soest}}
}

2015

Tianshi Wang, Tom Pfeiffer, Evelyn Regar, Wolfgang Wieser, Heleen van Beusekom, Charles T. Lancee, Geert Springeling, Ilona Krabbendam, Antonius F. W. van der Steen, Robert Huber, and Gijs van Soest,
Heartbeat OCT: in vivo intravascular megahertz-optical coherence tomography, Biomed. Opt. Express , vol. 6, no. 12, pp. 5021-5032, Dez. 2015. Optica Publishing Group.
DOI:10.1364/BOE.6.005021
Bibtex: BibTeX
@article{Wang:15,
author = {Tianshi Wang and Tom Pfeiffer and Evelyn Regar and Wolfgang Wieser and Heleen van Beusekom and Charles T. Lancee and Geert Springeling and Ilona Krabbendam and Antonius F.W. van der Steen and Robert Huber and Gijs van Soest},
journal = {Biomed. Opt. Express},
keywords = {Fiber optics imaging; Three-dimensional image acquisition; Medical optics instrumentation; Scanners; Endoscopic imaging; Medical and biological imaging; Optical coherence tomography; Image quality; Image registration; Imaging techniques; Laser modes; Mode locking; Optical coherence tomography},
number = {12},
pages = {5021--5032},
publisher = {Optica Publishing Group},
title = {Heartbeat OCT: in vivo intravascular megahertz-optical coherence tomography},
volume = {6},
month = {Dec},
year = {2015},
url = {https://opg.optica.org/boe/abstract.cfm?URI=boe-6-12-5021},
doi = {10.1364/BOE.6.005021},
abstract = {Cardiac motion artifacts, non-uniform rotational distortion and undersampling affect the image quality and the diagnostic impact of intravascular optical coherence tomography (IV-OCT). In this study we demonstrate how these limitations of IV-OCT can be addressed by using an imaging system that we called \&\#x201C;Heartbeat OCT\&\#x201D;, combining a fast Fourier Domain Mode Locked laser, fast pullback, and a micromotor actuated catheter, designed to examine a coronary vessel in less than one cardiac cycle. We acquired in vivo data sets of two coronary arteries in a porcine heart with both Heartbeat OCT, working at 2.88 MHz A-line rate, 4000 frames/s and 100 mm/s pullback speed, and with a commercial system. The in vivo results show that Heartbeat OCT provides faithfully rendered, motion-artifact free, fully sampled vessel wall architecture, unlike the conventional IV-OCT data. We present the Heartbeat OCT system in full technical detail and discuss the steps needed for clinical translation of the technology.},
}
Kathrin J. Mohler, Wolfgang Draxinger, Thomas Klein, Jan Philip Kolb, Wolfgang Wieser, Christos Haritoglou, Anselm Kampik, James G. Fujimoto, Aljoscha Neubauer, Armin Wolf, and Robert Huber,
Combined 60° Wide-Field Choroidal Thickness Maps and High-Definition En Face Vasculature Visualization Using Swept-Source Megahertz OCT at 1050 nm60° High-Definition MHz-OCT Imaging of the Choroid, Investigative Ophthalmology & Visual Science , vol. 56, no. 11, pp. 6284--6293, Okt. 2015.
DOI:10.1167/iovs.15-16670
Bibtex: BibTeX
@article{10.1167/iovs.15-16670,
    author = {Mohler, Kathrin J. and Draxinger, Wolfgang and Klein, Thomas and Kolb, Jan Philip and Wieser, Wolfgang and Haritoglou, Christos and Kampik, Anselm and Fujimoto, James G. and Neubauer, Aljoscha S. and Huber, Robert and Wolf, Armin},
    title = "{Combined 60° Wide-Field Choroidal Thickness Maps and High-Definition En Face Vasculature Visualization Using Swept-Source Megahertz OCT at 1050 nm}",
    journal = {Investigative Ophthalmology & Visual Science},
    volume = {56},
    number = {11},
    pages = {6284-6293},
    year = {2015},
    month = {10},
    abstract = "{   To demonstrate ultrahigh-speed swept-source optical coherence tomography (SS-OCT) at 1.68 million A-scans/s for choroidal imaging in normal and diseased eyes over a ∼60° field of view. To investigate and correlate wide-field three-dimensional (3D) choroidal thickness (ChT) and vascular patterns using ChT maps and coregistered high-definition en face images extracted from a single densely sampled Megahertz-OCT (MHz-OCT) dataset.    High-definition, ∼60° wide-field 3D datasets consisting of 2088 × 1024 A-scans were acquired using a 1.68 MHz prototype SS-OCT system at 1050 nm based on a Fourier-domain mode-locked laser. Nine subjects (nine eyes) with various chorioretinal diseases or without ocular pathology are presented. Coregistered ChT maps, choroidal summation maps, and depth-resolved en face images referenced to either the retinal pigment epithelium or the choroidal–scleral interface were generated using manual segmentation.    Wide-field ChT maps showed a large inter- and intraindividual variance in peripheral and central ChT. In only four of the nine eyes, the location with the largest ChT was coincident with the fovea. The anatomy of the large lumen vessels of the outer choroid seems to play a major role in determining the global ChT pattern. Focal ChT changes with large thickness gradients were observed in some eyes.    Different ChT and vascular patterns could be visualized over ∼60° in patients for the first time using OCT. Due to focal ChT changes, a high density of thickness measurements may be favorable. High-definition depth-resolved en face images are complementary to cross sections and thickness maps and enhance the interpretation of different ChT patterns.  }",
    issn = {1552-5783},
    doi = {10.1167/iovs.15-16670},
    url = {https://doi.org/10.1167/iovs.15-16670},
    eprint = {https://arvojournals.org/arvo/content\_public/journal/iovs/934564/i1552-5783-56-11-6284.pdf},
}
Lukas Reznicek, Jan Philip Kolb, Thomas Klein, Kathrin J. Mohler, Wolfgang Wieser, Robert Huber, Marcus Kernt, Josef Märtz, and Aljoscha Neubauer,
Wide-Field Megahertz OCT Imaging of Patients with Diabetic Retinopathy, Journal of Diabetes Research , vol. 2015, pp. 305084, 07 2015. Hindawi Publishing Corporation.
DOI:10.1155/2015/305084
Bibtex: BibTeX
@article{Reznicek2015,
   author = {Reznicek, Lukas and Kolb, Jan P. and Klein, Thomas and Mohler, Kathrin J. and Wieser, Wolfgang and Huber, Robert and Kernt, Marcus and Märtz, Josef and Neubauer, Aljoscha S.},
   title = {Wide-Field Megahertz OCT Imaging of Patients with Diabetic Retinopathy},
   journal = {Journal of Diabetes Research},
   volume = {2015, Article ID 305084},
   pages = {1-5},
   DOI = {10.1155/2015/305084},
   url = {http://dx.doi.org/10.1155/2015/305084},
   year = {2015},
keywords = {AG-Huber_OCT},
   type = {Journal Article}

}

Jan Philip Kolb, Thomas Klein, Wolfgang Wieser, Wolfgang Draxinger, and Robert Huber,
High definition in vivo retinal volumetric video rate OCT at 0.6 Giga-voxels per second, in Optical Coherence Imaging Techniques and Imaging in Scattering Media , Brett E. Bouma and Maciej Wojtkowski, Eds. SPIE, 072015. pp. 95410Z.
DOI:10.1117/12.2183768
Bibtex: BibTeX
@inproceedings{10.1117/12.2183768,
author = {Jan Philip Kolb and Thomas Klein and Wolfgang Wieser and Wolfgang Draxinger and Robert Huber},
title = {{High definition in vivo retinal volumetric video rate OCT at 0.6 Giga-voxels per second}},
volume = {9541},
booktitle = {Optical Coherence Imaging Techniques and Imaging in Scattering Media},
editor = {Brett E. Bouma and Maciej Wojtkowski},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {95410Z},
abstract = {We present full volumetric high speed OCT imaging of the retina with multiple settings varying in volume size and volume rate. The volume size ranges from 255x255 A-scans to 160x40 A-scans with 450 samples per depth scan with volume rates varying between 20.8 V/s for the largest volumes to 195.2 V/s for the smallest. The system is based on a 1060nm Fourier domain mode locked (FDML) laser with 1.6MHz line rate. Scanning along the fast axis is performed with a 2.7 kHz or 4.3 kHz resonant scanner operated in bidirectional scanning mode, while a standard galvo scanner is used for the slow axis. The performance is analyzed with respect to various potential applications, like intraoperative OCT.},
keywords = {Optical coherence tomography, OCT, tunable laser, Fourier domain mode locking, FDML, MHz-OCT},
year = {2015},
doi = {10.1117/12.2183768},
URL = {https://doi.org/10.1117/12.2183768}
}
Matthias Eibl, Sebastian Karpf, Wolfgang Wieser, Thomas Klein, and Robert Huber,
Hyperspectral stimulated Raman microscopy with two fiber laser sources, in Advanced Microscopy Techniques IV; and Neurophotonics II , SPIE, 072015. pp. 953604.
DOI:10.1117/12.2183822
Bibtex: BibTeX
@inproceedings{10.1117/12.2183822,
author = {Matthias Eibl and Sebastian Karpf and Wolfgang Wieser and Thomas Klein and Robert Huber},
title = {{Hyperspectral stimulated Raman microscopy with two fiber laser sources}},
volume = {9536},
booktitle = {Advanced Microscopy Techniques IV; and Neurophotonics II},
editor = {Emmanuel Beaurepaire and Peter T. C. So and Francesco Pavone and Elizabeth M. Hillman},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {953604},
abstract = {A fast all fiber based setup for stimulated Raman microscopy based on a rapidly wavelength swept cw-laser is presented. The applied Fourier domain mode locked (FDML) laser is a fiber ring laser, providing a continuously changing wavelength output over time. This fast swept source allows us to rapidly change the wavelength and, thereby the energy difference with respect to a single color pump laser. The pump laser is a master oscillator power amplifier based on a fiber amplified laser diode and a Raman shifter. By controlled variation of the relative timing between probe and pump laser with an arbitrary waveform generator, the Raman signals are encoded in time and they are directly acquired with a synchronized, fast analog-to-digital converter. This setup is capable of acquiring rapidly high resolution spectra (up to 0.5 cm<sup>-1</sup>) with shot noise limited sensitivity over a broadband (750 cm<sup>-1</sup> to 3150 cm<sup>-1</sup>) spectral region. Here, we show the performance of this system for imaging in the CH-stretch region around 3000 cm<sup>-1</sup> and in the fingerprint region around 1600 cm<sup>-1</sup>. We present hyperspectral images of a plant stem slice with molecular contrast of lignin and a lipid representative as well as images of PS (polystyrene) and PMMA (poly(methyl methacrylate) beads with an acquisition speed of 18 &mu;s per spectral point.},
keywords = {stimulated Raman, multiphoton, microscopy, coherent Raman, fiber laser, FDML, TICO, hyperspectral},
year = {2015},
doi = {10.1117/12.2183822},
URL = {https://doi.org/10.1117/12.2183822}
}
Sebastian Karpf, Matthias Eibl, and Robert Huber,
Nanosecond two-photon excitation fluorescence imaging with a multi color fiber MOPA laser, in Advanced Microscopy Techniques IV; and Neurophotonics II , Emmanuel Beaurepaire and Peter T. C. So and Francesco Pavone and Elizabeth M. Hillman, Eds. SPIE, 072015. pp. 953616.
DOI:10.1117/12.2183854
Bibtex: BibTeX
@inproceedings{10.1117/12.2183854,
author = {Sebastian Karpf and Matthias Eibl and Robert Huber},
title = {{Nanosecond two-photon excitation fluorescence imaging with a multi color fiber MOPA laser}},
volume = {9536},
booktitle = {Advanced Microscopy Techniques IV; and Neurophotonics II},
editor = {Emmanuel Beaurepaire and Peter T. C. So and Francesco Pavone and Elizabeth M. Hillman},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {953616},
abstract = {A system is presented that uses a fiber based Master Oscillator Power Amplifier (MOPA) with nanosecond-range pulses for two-photon excitation fluorescence (TPEF) imaging. The robust laser in the extended near infrared is based on an actively modulated electro-optical modulator (EOM), enabling free synchronization of the pulses to any other light source or detection unit. Pulses with a freely programmable duration between 0.4 and 10 ns are generated and then amplified to up to kilowatts of peak power with ytterbium doped fiber amplifiers (YDFA). Since we achieve peak power and duty cycles comparable to standard femto- and picosecond setups, the TPEF signal levels are similar, but realized with a robust and inexpensive fiber-based setup. The delivery fiber is further used as an optional, electronically controllable Raman shifter to effectively shift the 1064 nm light to 1122 nm and to 1186 nm. This allows imaging of a manifold of fluorophores, like e.g. TexasRed, mCherry, mRaspberry and many more. We show TPEF imaging of the autofluorescence of plant leaves of moss and algae, acquired in epi-direction. This modular laser unit can be integrated into existing systems as either a fiber-based, alignment free excitation laser or an extension for multi-modal imaging.},
keywords = {multi-photon imaging, TPEF, MOPA, TPA, fiber laser, Raman shifter, non-linear imaging, multi-modal imaging},
year = {2015},
doi = {10.1117/12.2183854},
URL = {https://doi.org/10.1117/12.2183854}
}
Wolfgang Wieser, Thomas Klein, Wolfgang Draxinger, and Robert Huber,
Fully automated 1.5 MHz FDML laser with more than 100mW output power at 1310 nm, in Optical Coherence Imaging Techniques and Imaging in Scattering Media , Brett E. Bouma and Maciej Wojtkowski, Eds. SPIE, 072015. pp. 954116.
DOI:10.1117/12.2183431
Bibtex: BibTeX
@inproceedings{10.1117/12.2183431,
author = {Wolfgang Wieser and Thomas Klein and Wolfgang Draxinger and Robert Huber},
title = {{Fully automated 1.5 MHz FDML laser with more than 100mW output power at 1310 nm}},
volume = {9541},
booktitle = {Optical Coherence Imaging Techniques and Imaging in Scattering Media},
editor = {Brett E. Bouma and Maciej Wojtkowski},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {954116},
abstract = {While FDML lasers with MHz sweep speeds have been presented five years ago, these devices have required manual control for startup and operation. Here, we present a fully self-starting and continuously regulated FDML laser with a sweep rate of 1.5 MHz. The laser operates over a sweep range of 115 nm centered at 1315 nm, and provides very high average output power of more than 100 mW. We characterize the laser performance, roll-off, coherence length and investigate the wavelength and phase stability of the laser output under changing environmental conditions. The high output power allows optical coherence tomography (OCT) imaging with an OCT sensitivity of 108 dB at 1.5 MHz.},
keywords = {OCT, optical coherence tomography, swept laser, wavelength-swept laser, fiber laser, MHz-OCT, Fourier-domain mode-locking, FDML},
year = {2015},
doi = {10.1117/12.2183431},
URL = {https://doi.org/10.1117/12.2183431}
}
Sebastian Karpf, Matthias Eibl, Wolfgang Wieser, Thomas Klein, and Robert Huber,
Time-encoded Raman scattering (TICO-Raman) with Fourier domain mode locked (FDML) lasers, in Optical Coherence Imaging Techniques and Imaging in Scattering Media , Brett E. Bouma and Maciej Wojtkowski, Eds. SPIE, 072015. pp. 95410F.
DOI:10.1117/12.2183859
Bibtex: BibTeX
@inproceedings{10.1117/12.2183859,
author = {Sebastian Karpf and Matthias Eibl and Wolfgang Wieser and Thomas Klein and Robert Huber},
title = {{Time-encoded Raman scattering (TICO-Raman) with Fourier domain mode locked (FDML) lasers}},
volume = {9541},
booktitle = {Optical Coherence Imaging Techniques and Imaging in Scattering Media},
editor = {Brett E. Bouma and Maciej Wojtkowski},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {95410F},
abstract = {We present a new concept for performing stimulated Raman spectroscopy and microscopy by employing rapidly wavelength swept Fourier Domain Mode locked (FDML) lasers [1]. FDML lasers are known for fastest imaging in swept-source optical coherence tomography [2, 3]. We employ this continuous and repetitive wavelength sweep to generate broadband, high resolution stimulated Raman spectra with a new, time-encoded (TICO) concept [4]. This allows for encoding and detecting the stimulated Raman gain on the FDML laser intensity directly in time. Therefore we use actively modulated pump lasers, which are electronically synchronized to the FDML laser, in combination with a fast analog-to-digital converter (ADC) at 1.8 GSamples/s. We present hyperspectral Raman images with color-coded, molecular contrast.},
keywords = {swept lasers, FDML, TICO-Raman, fiber lasers, stimulated Raman microscopy, Raman spectroscopy, molecular contrast, multi-modal imaging},
year = {2015},
doi = {10.1117/12.2183859},
URL = {https://doi.org/10.1117/12.2183859}
}
Christian Jirauschek, and Robert Huber,
Wavelength shifting of intra-cavity photons: Adiabatic wavelength tuning in rapidly wavelength-swept lasers, Biomed. Opt. Express , vol. 6, no. 7, pp. 2448-2465, 07 2015. Optica Publishing Group.
DOI:10.1364/BOE.6.002448
Bibtex: BibTeX
@article{Jirauschek:15,
author = {Christian Jirauschek and Robert Huber},
journal = {Biomed. Opt. Express},
keywords = {Laser theory; Lasers, tunable; Optical coherence tomography; Vertical cavity surface emitting lasers; Distributed Bragg reflectors; Laser light; Laser sources; Quantum well lasers; Swept lasers; Vertical cavity surface emitting lasers},
number = {7},
pages = {2448--2465},
publisher = {Optica Publishing Group},
title = {Wavelength shifting of intra-cavity photons: Adiabatic wavelength tuning in rapidly wavelength-swept lasers},
volume = {6},
month = {Jul},
year = {2015},
url = {https://opg.optica.org/boe/abstract.cfm?URI=boe-6-7-2448},
doi = {10.1364/BOE.6.002448},
abstract = {We analyze the physics behind the newest generation of rapidly wavelength tunable sources for optical coherence tomography (OCT), retaining a single longitudinal cavity mode during operation without repeated build up of lasing. In this context, we theoretically investigate the currently existing concepts of rapidly wavelength-swept lasers based on tuning of the cavity length or refractive index, leading to an altered optical path length inside the resonator. Specifically, we consider vertical-cavity surface-emitting lasers (VCSELs) with microelectromechanical system (MEMS) mirrors as well as Fourier domain mode-locked (FDML) and Vernier-tuned distributed Bragg reflector (VT-DBR) lasers. Based on heuristic arguments and exact analytical solutions of Maxwell's equations for a fundamental laser resonator model, we show that adiabatic wavelength tuning is achieved, i.e., hopping between cavity modes associated with a repeated build up of lasing is avoided, and the photon number is conserved. As a consequence, no fundamental limit exists for the wavelength tuning speed, in principle enabling wide-range wavelength sweeps at arbitrary tuning speeds with narrow instantaneous linewidth.},
}
Robert Huber,
4-D Real-Time Optical Coherence Tomography, Opt. Photon. News , vol. 26, no. 6, pp. 32-39, 06 2015. Optica Publishing Group.
DOI:10.1364/OPN.26.6.000032
Bibtex: BibTeX
@article{Huber:15,
author = {Robert Huber},
journal = {Opt. Photon. News},
keywords = {Image processing; Optical coherence tomography; Lasers, tunable; Medical optics and biotechnology; Optical coherence tomography; Image processing; Imaging techniques; Line scan cameras; Medical imaging; Optical coherence tomography; Three dimensional imaging},
number = {6},
pages = {32--39},
publisher = {Optica Publishing Group},
title = {4-D Real-Time Optical Coherence Tomography},
volume = {26},
month = {Jun},
year = {2015},
url = {https://www.optica-opn.org/abstract.cfm?URI=opn-26-6-32},
doi = {10.1364/OPN.26.6.000032},
abstract = {Advances in OCT techniques, combined with the processing power of moderncomputer hardware, are adding a new dimension---time---to a familiar 3-D imaging method.The result could be new applications in research and the biomedicalclinic.},
}
Christian Jirauschek, and Robert Huber,
Modeling and analysis of polarization effects in Fourier domain mode-locked lasers, Opt. Lett. , vol. 40, no. 10, pp. 2385-2388, 05 2015. Optica Publishing Group.
DOI:10.1364/OL.40.002385
Bibtex: BibTeX
@article{Jirauschek:15,
author = {Christian Jirauschek and Robert Huber},
journal = {Opt. Lett.},
keywords = {Laser theory; Lasers, tunable; Optical coherence tomography; Birefringence; Polarization; Pulses; Cross phase modulation; Mode locking; Optical components; Picosecond pulses; Polarization mode dispersion; Pulse generation},
number = {10},
pages = {2385--2388},
publisher = {Optica Publishing Group},
title = {Modeling and analysis of polarization effects in Fourier domain mode-locked lasers},
volume = {40},
month = {May},
year = {2015},
url = {https://opg.optica.org/ol/abstract.cfm?URI=ol-40-10-2385},
doi = {10.1364/OL.40.002385},
abstract = {We develop a theoretical model for Fourier domain mode-locked (FDML) lasers in a non-polarization-maintaining configuration, which is the most widely used type of FDML source. This theoretical approach is applied to analyze a widely wavelength-swept FDML setup, as used for picosecond pulse generation by temporal compression of the sweeps. We demonstrate that good agreement between simulation and experiment can only be obtained by including polarization effects due to fiber bending birefringence, polarization mode dispersion, and cross-phase modulation into the theoretical model. Notably, the polarization dynamics are shown to have a beneficial effect on the instantaneous linewidth, resulting in improved coherence and thus compressibility of the wavelength-swept FDML output.},
}
Jan Philip Kolb, Thomas Klein, Corinna L. Kufner, Wolfgang Wieser, Aljoscha Neubauer, and Robert Huber,
Ultra-widefield retinal MHz-OCT imaging with up to 100 degrees viewing angle, Biomed. Opt. Express , vol. 6, no. 5, pp. 1534--1552, 05 2015. Optica Publishing Group.
DOI:10.1364/BOE.6.001534
Bibtex: BibTeX
@article{Kolb:15,
author = {Jan Philip Kolb and Thomas Klein and Corinna L. Kufner and Wolfgang Wieser and Aljoscha S. Neubauer and Robert Huber},
journal = {Biomed. Opt. Express},
keywords = {Medical optics instrumentation; Lasers, fiber; Medical and biological imaging; Ophthalmic optics and devices ; Optical coherence tomography; Adaptive optics; Full field optical coherence tomography; Image quality; Imaging techniques; Laser scanning; Three dimensional imaging},
number = {5},
pages = {1534--1552},
publisher = {Optica Publishing Group},
title = {Ultra-widefield retinal MHz-OCT imaging with up to 100 degrees viewing angle},
volume = {6},
month = {May},
year = {2015},
url = {https://opg.optica.org/boe/abstract.cfm?URI=boe-6-5-1534},
doi = {10.1364/BOE.6.001534},
abstract = {We evaluate strategies to maximize the field of view (FOV) of in vivo retinal OCT imaging of human eyes. Three imaging modes are tested: Single volume imaging with 85{\textdegree} FOV as well as with 100{\textdegree} and stitching of five 60{\textdegree} images to a 100{\textdegree} mosaic (measured from the nodal point). We employ a MHz-OCT system based on a 1060nm Fourier domain mode locked (FDML) laser with a depth scan rate of 1.68MHz. The high speed is essential for dense isotropic sampling of the large areas. Challenges caused by the wide FOV are discussed and solutions to most issues are presented. Detailed information on the design and characterization of our sample arm optics is given. We investigate the origin of an angle dependent signal fall-off which we observe towards larger imaging angles. It is present in our 85{\textdegree} and 100{\textdegree} single volume images, but not in the mosaic. Our results suggest that 100{\textdegree} FOV OCT is possible with current swept source OCT technology.},
}
Sebastian Karpf, Matthias Eibl, Wolfgang Wieser, Thomas Klein, and Robert Huber,
A Time-Encoded Technique for fibre-based hyperspectral broadband stimulated Raman microscopy, Nature Communications , vol. 6, no. 1, pp. 6784, 04 2015.
DOI:10.1038/ncomms7784
Bibtex: BibTeX
@Article{HU_2015_Karpf_a,
  Title                    = {A Time-Encoded Technique for fibre-based hyperspectral broadband stimulated Raman microscopy},
  Author                   = {Karpf, Sebastian and Eibl, Matthias and Wieser, Wolfgang and Klein, Thomas and Huber, Robert},
  Journal                  = {Nature Communications},
  Year                     = {2015},
  Volume = {6},
  pages = {6784 1--6},
keywords = {AG-Huber_NL},
  Doi                      = {10.1038/ncomms7784}
}
Tom Pfeiffer, Wolfgang Wieser, Thomas Klein, Markus Petermann, Jan Philip Kolb, Matthias Eibl, and Robert Huber,
Flexible A-scan rate MHz OCT: computational downscaling by coherent averaging, in Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XX , Joseph A. Izatt and James G. Fujimoto and Valery V. Tuchin, Eds. SPIE, 042015. pp. 96970S-96970S-5.
DOI:10.1117/12.2214788
Bibtex: BibTeX
@inproceedings{10.1117/12.2214788,
author = {Tom Pfeiffer and Wolfgang Wieser and Thomas Klein and Markus Petermann and Jan-Phillip Kolb and Matthias Eibl and Robert Huber},
title = {{Flexible A-scan rate MHz OCT: computational downscaling by coherent averaging}},
volume = {9697},
booktitle = {Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XX},
editor = {Joseph A. Izatt and James G. Fujimoto and Valery V. Tuchin},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {96970S},
abstract = {In order to realize fast OCT-systems with adjustable line rate, we investigate averaging of image data from an FDML based
MHz-OCT-system. The line rate can be reduced in software and traded in for increased system sensitivity and image
quality. We compare coherent and incoherent averaging to effectively scale down the system speed of a 3.2 MHz FDML
OCT system to around 100 kHz in postprocessing. We demonstrate that coherent averaging is possible with MHz systems
without special interferometer designs or digital phase stabilisation. We show OCT images of a human finger knuckle joint
in vivo with very high quality and deep penetration.},
keywords = {Optical coherence tomography, OCT, Fourier domain mode locking, FDML, MHz OCT, averaging, tunable laser},
year = {2016},
doi = {10.1117/12.2214788},
URL = {https://doi.org/10.1117/12.2214788}
}
Jan Philip Kolb, Thomas Klein, Wolfgang Wieser, Wolfgang Draxinger, and Robert Huber,
Full volumetric video rate OCT of the posterior eye with up to 195.2 volumes/s, in Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XIX , James G. Fujimoto and Joseph A. Izatt and Valery V. Tuchin, Eds. SPIE, 032015. pp. 931202.
DOI:10.1117/12.2077147
Bibtex: BibTeX
@inproceedings{10.1117/12.2077147,
author = {Jan Philip Kolb and Thomas Klein and Wolfgang Wieser and Wolfgang Draxinger and Robert Huber},
title = {{Full volumetric video rate OCT of the posterior eye with up to 195.2 volumes/s}},
volume = {9312},
booktitle = {Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XIX},
editor = {James G. Fujimoto and Joseph A. Izatt and Valery V. Tuchin},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {931202},
abstract = {Full volumetric high speed OCT imaging of the retina with multiple settings varying in volume size and volume rate is
presented. The volume size ranges from 255x255 A-scans to 160x40 A-scans with 450 samples per depth scan. The
volume rates vary between 20.8 V/s for the largest volumes to 195.2 V/s for the smallest. The system is based on a
1060nm Fourier domain mode locked (FDML) laser with 1.6MHz line rate. Scanning along the fast axis is performed
with a 2.7 kHz or 4.3 kHz resonant scanner operated in bidirectional scanning mode, while a standard galvo scanner is
used for the slow axis. The performance is analyzed with respect to various potential applications, like intraoperative
OCT.},
keywords = {Optical coherence tomography, OCT, tunable laser, Fourier domain mode lockng, FDML, MHz OCT},
year = {2015},
doi = {10.1117/12.2077147},
URL = {https://doi.org/10.1117/12.2077147}
}
Jan Philip Kolb, Philipp Schwarz, Thomas Klein, Wolfgang Wieser, and Robert Huber,
Dual parametric compounding approach for speckle reduction in OCT, in Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XIX , James G. Fujimoto and Joseph A. Izatt and Valery V. Tuchin, Eds. SPIE, 032015. pp. 93123G.
DOI:10.1117/12.2077659
Bibtex: BibTeX
@inproceedings{10.1117/12.2077659,
author = {Jan Philip Kolb and Philipp Schwarz and Thomas Klein and Wolfgang Wieser and Robert Huber},
title = {{Dual parametric compounding approach for speckle reduction in OCT}},
volume = {9312},
booktitle = {Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XIX},
editor = {James G. Fujimoto and Joseph A. Izatt and Valery V. Tuchin},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {93123G},
abstract = {OCT as a coherent imaging technique inherently suffers from speckle. We present a new dual parametric compounding approach to reduce speckle. The approach is to acquire several OCT volumes with different numerical apertures (NAs). Then in post processing, a first spatial compounding step is performed by averaging of adjacent B-frames. In a second step data from the different volume is averaged. Retinal imaging data comparing this idea with standard spatial compounding is presented and analyzed and necessary parameters such as the required variation of the NA and number of different NAs are discussed},
keywords = {Optical coherence tomography, OCT, tunable laser, Fourier domain mode lockng, FDML, MHz OCT},
year = {2015},
doi = {10.1117/12.2077659},
URL = {https://doi.org/10.1117/12.2077659}
}

2014

Yaokun Zhang, Tom Pfeiffer, Marcel Weller, Wolfgang Wieser, Robert Huber, Jörg Raczkowsky, Jörg Schipper, Heinz Wörn, and Thomas Klenzner,
Optical coherence tomography guided laser cochleostomy: towards the accuracy on tens of micrometer scale, BioMed research international , vol. 2014, pp. 251814, 09 2014. Hindawi Publishing Corporation.
DOI:10.1155/2014/251814
Bibtex: BibTeX
@Article{HU_2014_Zhang_a,
  Title                    = {{Optical coherence tomography guided laser cochleostomy: towards the accuracy on tens of micrometer scale}},
  Author                   = {Zhang, Yaokun and Pfeiffer, Tom and Weller, Marcel and Wieser, Wolfgang and Huber, Robert and Raczkowsky, J\"{o}rg and Schipper, J\"{o}rg and W\"{o}rn, Heinz and Klenzner, Thomas},
  Journal                  = {BioMed research international},
  Year                     = {2014},
  Month                    = jan,
  Pages                    = {251814--24},
  Volume                   = {2014},
  Doi                      = {10.1155/2014/251814},
  ISSN                     = {2314-6141},
keywords = {AG-Huber_OCT},
  Url                      = {http://www.hindawi.com/journals/bmri/2014/251814/}
}
Wolfgang Wieser, Wolfgang Draxinger, Thomas Klein, Sebastian Karpf, Tom Pfeiffer, and Robert Huber,
High definition live 3D-OCT in vivo: design and evalution of 4D-OCT engine with 1 GVoxel/s, Biomed. Opt. Express , vol. 5, no. 9, pp. 2963--77, 09 2014. Optica Publishing Group.
DOI:10.1364/BOE.5.002963
Bibtex: BibTeX
@article{Wieser:14,
author = {Wolfgang Wieser and Wolfgang Draxinger and Thomas Klein and Sebastian Karpf and Tom Pfeiffer and Robert Huber},
journal = {Biomed. Opt. Express},
keywords = {Optical coherence tomography; Lasers, tunable; Optical coherence tomography; Endoscopic imaging; Full field optical coherence tomography; Functional imaging; Image quality; Ophthalmic imaging; Vertical cavity surface emitting lasers},
number = {9},
pages = {2963--2977},
publisher = {Optica Publishing Group},
title = {High definition live 3D-OCT in vivo: design and evaluation of a 4D OCT engine with 1 GVoxel/s},
volume = {5},
month = {Sep},
year = {2014},
url = {https://opg.optica.org/boe/abstract.cfm?URI=boe-5-9-2963},
doi = {10.1364/BOE.5.002963},
abstract = {We present a 1300 nm OCT system for volumetric real-time live OCT acquisition and visualization at 1 billion volume elements per second. All technological challenges and problems associated with such high scanning speed are discussed in detail as well as the solutions. In one configuration, the system acquires, processes and visualizes 26 volumes per second where each volume consists of 320 x 320 depth scans and each depth scan has 400 usable pixels. This is the fastest real-time OCT to date in terms of voxel rate. A 51 Hz volume rate is realized with half the frame number. In both configurations the speed can be sustained indefinitely. The OCT system uses a 1310 nm Fourier domain mode locked (FDML) laser operated at 3.2 MHz sweep rate. Data acquisition is performed with two dedicated digitizer cards, each running at 2.5 GS/s, hosted in a single desktop computer. Live real-time data processing and visualization are realized with custom developed software on an NVidia GTX 690 dual graphics processing unit (GPU) card. To evaluate potential future applications of such a system, we present volumetric videos captured at 26 and 51 Hz of planktonic crustaceans and skin.},
}
Sebastian Karpf, Matthias Eibl, Wolfgang Wieser, Thomas Klein, and Robert Huber,
Time-Encoded Raman: Fiber-based, hyperspectral, broadband stimulated Raman microscopy, ArXiv e-prints , 05 2014.
DOI:10.48550/arXiv.1405.4181
Bibtex: BibTeX
@Article{HU_2014_Karpf_a,
  Title                    = {{Time-Encoded Raman: Fiber-based, hyperspectral, broadband stimulated Raman microscopy}},
  Author                   = {Karpf, Sebastian and Eibl, Matthias and Wieser, Wolfgang and Klein, Thomas and Huber, Robert},
  journal = {ArXiv e-prints},
  Year                     = {2014},
  Archiveprefix            = {arXiv},
  Arxivid                  = {1405.4181},
  Eprint                   = {1405.4181},
keywords = {AG-Huber_NL},
  Url                      = {http://arxiv.org/abs/1405.4181}
}
Lukas Reznicek, Thomas Klein, Wolfgang Wieser, Marcus Kernt, Armin Wolf, Christos Haritoglou, Anselm Kampik, Robert Huber, and Aljoscha Neubauer,
Megahertz ultra-wide-field swept-source retina optical coherence tomography compared to current existing imaging devices., Graefe's Archive for Clinical and Experimental Ophthalmology , vol. 252, no. 6, pp. 1009-1016, 05 2014.
DOI:10.1007/s00417-014-2640-4
Bibtex: BibTeX
@Article{HU_2014_Reznicek_a,
  Title                    = {{Megahertz ultra-wide-field swept-source retina optical coherence tomography compared to current existing imaging devices.}},
  Author                   = {Reznicek, Lukas and Klein, Thomas and Wieser, Wolfgang and Kernt, Marcus and Wolf, Armin and Haritoglou, Christos and Kampik, Anselm and Huber, Robert and Neubauer, Aljoscha S},
  Journal                  = {Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv f\"{u}r klinische und experimentelle Ophthalmologie},
  Year                     = {2014},

  Month                    = jun,
  Number                   = {6},
  Pages                    = {1009--16},
  Volume                   = {252},

  Doi                      = {10.1007/s00417-014-2640-4},
  ISSN                     = {1435-702X},
keywords = {AG-Huber_OCT},
  Url                      = {http://link.springer.com/article/10.1007\%2Fs00417-014-2640-4}
}
Thomas Klein, Wolfgang Draxinger, Kathrin J. Mohler, Jan Philip Kolb, Wolfgang Wieser, Anselm Kampik, Aljoscha Neubauer, Armin Wolf, and Robert Huber,
Wide-field choroidal thickness and en-face maps of patients created with MHz-OCT, Investigative Ophthalmology & Visual Science , vol. 55, no. 13, pp. 1620, 04 2014.
Weblink: https://iovs.arvojournals.org/article.aspx?articleid=2266882
Bibtex: BibTeX
@article{Klein2014,
   author = {Klein, Thomas and Draxinger, Wolfgang and Mohler, Kathrin and Kolb, Jan Philip and Wieser, Wolfgang and Kampik, Anselm and Neubauer, Aljoscha S. and Wolf, Armin and Huber, Robert},
   title = {Wide-field choroidal thickness and en-face maps of patients created with MHz-OCT},
   journal = {Investigative Ophthalmology & Visual Science},
   volume = {55},
   number = {13},
   pages = {1620-1620},
   abstract = { PurposeTo study the feasibility of simultaneous peripheral and central choroidal thickness measurement and en-face visualization in patients with a variety of diseases, using a single high-resolution wide-field MHz-OCT dataset spanning more than 50 degrees field of view.  MethodsIn this retrospective study, choroidal morphology of 29 patients imaged with MHz-OCT was assessed. MHz-OCT is a custom SS-OCT operating at 1060nm and an axial line rate of 1.68MHz. The high speed, more than 30 times faster than current commercial devices, enabled a very high resolution scan protocol of 2088x1024 A-scans over a wide field of ~60 degrees. However, due to the very high speed, signal strength is lower compared to slower devices. Hence, thickness and structure maps were only created for selected datasets: The positions of Bruch’s membrane and choroid sclera junction were determined manually by a trained observer a subset of all A-scans, from which thickness and intensity maps were created.  ResultsDespite relative low signal strength, the choroid sclera junction could be clearly observed over the entire unshadowed image area in 15 of 29 patients. Apart from shadowing, visibility of this junction shows strong variation even within a single dataset due to varying retinal thickness, eye-blinks, saccades and retinal curvature. Thus, thickness could be evaluated at least in some areas for all 29 patients, especially in the periphery. Moreover, choroidal thickness varied considerably intra- and interindividually. In two patients, abrupt changes of the choroid were observed in the temporal periphery, which may resemble morphology or imaging artifact. In addition to thickness, en-face choroidal structure maps were extracted from the segmented OCT datasets. Visibility of choroidal vasculature in these maps correlates with choroidal thickness.  ConclusionsChoroidal thickness and structure in patients could be visualized over large areas for the first time. Due to focal choroidal thickness changes with large thickness gradients, high-density scan protocols may be favorable for OCT-based investigations of the choroid. En-face images of the choroid can be extracted from these high-resolution datasets, but the influence of choroidal thickness on the image information should be taken into account. Choroidal en-face image (top), color-coded thickness map with superimposed structural image (middle) and OCT B-frame (bottom) for two eyes (A,B).},
   ISSN = {1552-5783},
   url = {http://dx.doi.org/},
   year = {2014},
keywords = {AG-Huber_OCT},
   type = {Journal Article}
}
Jan Philip Kolb, Thomas Klein, Kathrin J. Mohler, Wolfgang Wieser, Lukas Reznicek, Marcus Kernt, Anselm Kampik, Aljoscha Neubauer, and Robert Huber,
Widefield Megahertz (MHz) OCT of diabetic retinopathy, Investigative Ophthalmology & Visual Science , vol. 55, no. 13, pp. 5018, 04 2014.
Weblink: https://iovs.arvojournals.org/article.aspx?articleid=2270590
Bibtex: BibTeX
@article{Kolb2014,
   author = {Kolb, Jan Philip and Klein, Thomas and Mohler, Kathrin and Wieser, Wolfgang and Reznicek, Lukas and Kernt, Marcus and Kampik, Anselm and Neubauer, Aljoscha S. and Huber, Robert},
   title = {Widefield Megahertz (MHz) OCT of diabetic retinopathy},
   journal = {Investigative Ophthalmology & Visual Science},
   volume = {55},
   number = {13},
   pages = {5018-5018},
   abstract = { PurposeTo investigate morphological appearance of diabetic retinopathy and laser effects in panretinal laser photocoagulation with a widefield MHz OCT (60° field of view, 120° center angle).  MethodsA custom swept-source OCT device with a 1060nm Fourier-domain mode-locked laser source achieving a line rate of 1.68MHz was used to investigate 15 consecutive patients with diabetic retinopathy. Within 1.82s datasets consisting of 2088x1024 A-scans over 60° were acquired. The densely sampled three dimensional datasets were investigated in various B-Scan cross-sections as well as en-face images and 3D reconstructions. Selected findings were compared with SLO images from a widefield SLO (Optos, Dunfermeline, UK).  ResultsOn the densely sampled 3D and en-face images, hard exsudates, peripheral laser spots as well as proliferative neovascularization were readily detected. Characteristic structural changes resulting from laser burns could easily be visualized across the whole field of view in the OCT datasets. In addition, depth-scans and B-scans allowed to identify additional structural changes including IS/OS disruption, RPE detachment or neovascularisation reaching into the vitreous across the field of view.  ConclusionsThree dimensional visualization of the retina over 60° field of view with a MHz OCT is feasible in patients with diabetic retinopathy. It might allow additional clinical insights in peripheral changes such as laser spots or retinal neovascularisation. 3D reconstruction of OCT dataset of patient with diabetic retinopathy with neovascularization (green), hard exsudates (yellow), epiretinal membrane and peripheral retinal scars after panretinal laser treatment (blue). Indications with arrows are examplatory. Top: En-face of same patient as in figure 1. Red line indicates the position of B-Frame below. Retinal scars due to focal laser coagulation temporal of the fovea visible. Bottom: Neovascularisation (green) reaching into the vitreous is visible on the left side. Retinal scars especially on RPE level due to panretinal laser treatment (blue) are observable.},
   ISSN = {1552-5783},
   url = {http://dx.doi.org/},
   year = {2014},
keywords = {AG-Huber_OCT},
   type = {Journal Article}
}

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