Research

The research group led by Robert Huber conducts research in the fields of optical coherence tomography (OCT), non-linear imaging and laser physics. Here, work is mainly done on novel pico second lasers and on Fourier domain mode-locked (FDML) lasers. This laser concept was developed by Robert Huber and enables the realization of particularly fast tunable laser light sources. The research focus here is on further technological development, understanding of the physical processes and also on the implementation of FDML lasers for OCT applications. Besides OCT, FDML lasers are also used for nonlinear imaging and spectroscopy.

Another focus is on optical coherence tomography with tunable light sources (swept source OCT, SS-OCT). Here, among other applications, the in-house developed FDML lasers are used for ultrafast imaging to generate cross-sectional images of biological tissues such as skin or eye. Due to the high tuning rate, applications like VR-OCT, which displays entire volumes in a virtual environment with real-time video repetition rates, are possible.

With non-linear optical imaging, the group is pursuing further imaging techniques. Research areas are in time-encoded (TICO) Raman spectroscopy and microscopy, two-photon fluorescence microscopy (TPEF), and two-photon single-pulse fluorescence lifetime imaging (SP-FLIM). These techniques use novel pico second lasers that are also being researched and developed in the group.

Our main research topics:

Publications

2014

Karsten Ulrich Kortuem, Jan Philip Kolb, Thomas Klein, Kathrin J. Mohler, Anselm Kampik, Aljoscha Neubauer, Wolfgang Wieser, Robert Huber, and Christos Haritoglou,
Wide Field MHz OCT imaging of the vitreoretinal interface, Invest. Ophthalmol. Vis. Sci. , vol. 55, no. 13, pp. 1619, 04 2014.
Weblink: https://iovs.arvojournals.org/article.aspx?articleid=2266879
Bibtex: BibTeX
@article{Kortuem2014,
   author = {Kortuem, Karsten Ulrich and Kolb, Jan Philip and Klein, Thomas and Mohler, Kathrin and Kampik, Anselm and Neubauer, Aljoscha S. and Wieser, Wolfgang and Huber, Robert and Haritoglou, Christos},
   title = {Wide Field MHz OCT imaging of the vitreoretinal interface},
   journal = {Investigative Ophthalmology & Visual Science},
   volume = {55},
   number = {13},
   pages = {1619-1619},
   abstract = { PurposeTo investigate changes caused by vitreoretinal interface disease with a multi-MHz OCT over a wide field of view of 60°.  MethodsWe used custom swept-source OCT device with a 1060nm Fourier-domain mode-locked laser source achieving a line rate of 1.68MHz. Within 1.82s datasets consisting of 2088x1024 A-scans over 60° were acquired from 5 patients with vitreoretinal traction due to VMTS and 3 patients with vascular pathology. The densely sampled three dimensional datasets were investigated in B-Scan cross-sections as well as en-face images and 3D reconstructions.  ResultsVitreoretinal traction could be imaged well in most of the cases, although the current sensitivity of the system limited image quality. Across the whole 60° field of view in the OCT datasets vitreoretinal tractions could be topographically assessed, always including the macula and optic disc, where vitreous anchorage could be shown. By means of the depth-scans as part of the 3D OCT volume we could image traction-associated retinal changes such as retinal elevation or RPE detachment.  ConclusionsThis unique three dimensional visualization of the retina over 60° field of view with a MHz OCT is feasible in patients with vitreoretinal interface disease and might offer additional clinical insights on the three-dimensional topology of tractional changes. Three dimensional Wide Field MHz OCT retinal and vitreous visualization.},
   ISSN = {1552-5783},
   url = {http://dx.doi.org/},
   year = {2014},
keywords = {AG-Huber_OCT},
   type = {Journal Article}
}
Wolfgang Wieser, Wolfgang Draxinger, Thomas Klein, and Tom Pfeiffer,
A 4-D OCT Engine with 1 GVoxel/s, Optics and Photonics News , vol. 25, no. 12, pp. 36, 2014. OSA.
Weblink: https://www.optica-opn.org/home/articles/volume_25/december_2014/extras/a_4-d_oct_engine_with_1_gvoxel_s/#.VcH21Pl5raw
Bibtex: BibTeX
@Article{HU_2014_Wieser_b,
  Title                    = {{A 4-D OCT Engine with 1 GVoxel/s}},
  Author                   = {Wieser, Wolfgang and Draxinger, Wolfgang and Klein, Thomas and Karpf, Sebastian and Pfeiffer, Tom and Huber, Robert},
  Journal                  = {Optics and Photonics News},
  Year                     = {2014},

  Month                    = dec,
  Number                   = {12},
  Pages                    = {36 },
  Volume                   = {25},
keywords = {AG-Huber_FDML, AG-Huber_OCT},

  Publisher                = {OSA},
  Url                      = { http://www.osa-opn.org/home/articles/volume_25/december_2014/extras/a_4-d_oct_engine_with_1_gvoxel_s/#.VcH21Pl5raw}
}
Sebastian Karpf, Matthias Eibl, Wolfgang Wieser, Thomas Klein, and Robert Huber,
Hyperspectral Stimulated Raman Microscopy with Fiber-based, Rapidly Wavelength Swept cw-Lasers, in CLEO: 2014 , Optica Publishing Group, 2014. pp. SM3P.3.
DOI:10.1364/CLEO_SI.2014.SM3P.3
Bibtex: BibTeX
@inproceedings{Karpf:14,
author = {Sebastian Karpf and Matthias Eibl and Wolfgang Wieser and Thomas Klein and Robert Huber},
booktitle = {CLEO: 2014},
journal = {CLEO: 2014},
keywords = {Lasers, tunable; Scattering, stimulated Raman; Raman microscopy; Biological imaging; Medical imaging; Optical coherence tomography; Raman microscopy; Raman scattering; Swept lasers},
pages = {SM3P.3},
publisher = {Optica Publishing Group},
title = {Hyperspectral Stimulated Raman Microscopy with Fiber-based, Rapidly Wavelength Swept cw-Lasers},
year = {2014},
url = {https://opg.optica.org/abstract.cfm?URI=CLEO_SI-2014-SM3P.3},
doi = {10.1364/CLEO_SI.2014.SM3P.3},
abstract = {A hyperspectral stimulated Raman microscopy system using rapidly wavelength swept lasers is presented. Imaging of biological samples with shot noise limited detection is demonstrated with the fiber based setup.},
}
Matthias Eibl, Sebastian Karpf, Wolfgang Wieser, Thomas Klein, and Robert Huber,
Broadband, High Resolution Stimulated Raman Spectroscopy with Rapidly Wavelength Swept cw-Lasers, in CLEO: 2014 , Optica Publishing Group, 2014. pp. ATu3P.4.
DOI:10.1364/CLEO_AT.2014.ATu3P.4
Bibtex: BibTeX
@inproceedings{Eibl:14,
author = {Matthias Eibl and Sebastian Karpf and Wolfgang Wieser and Thomas Klein and Robert Huber},
booktitle = {CLEO: 2014},
journal = {CLEO: 2014},
keywords = {Lasers, tunable; Scattering, stimulated Raman; Spectroscopy, Raman; Laser light; Laser sources; Master oscillator power amplifiers; Raman spectroscopy; Self phase modulation; Stimulated Raman scattering},
pages = {ATu3P.4},
publisher = {Optica Publishing Group},
title = {Broadband, High Resolution Stimulated Raman Spectroscopy with Rapidly Wavelength Swept cw-Lasers},
year = {2014},
url = {https://opg.optica.org/abstract.cfm?URI=CLEO_AT-2014-ATu3P.4},
doi = {10.1364/CLEO_AT.2014.ATu3P.4},
abstract = {A fast all fiber based setup for stimulated Raman spectroscopy with a rapidly wavelength swept cw-laser is presented. It enables flexible acquisition of broadband (750 cm{\textminus}1 to 3150 cm{\textminus}1) spectra with high resolution (0.5 cm{\textminus}1).},
}

2013

WooJhon Choi, Kathrin J. Mohler, Benjamin Potsaid, Chen D. Lu, Jonathan J. Liu, Vijaysekhar Jayaraman, Alex E. Cable, Jay S. Duker, Robert Huber, and James G. Fujimoto,
Choriocapillaris and choroidal microvasculature imaging with ultrahigh speed OCT angiography, PLOS ONE , vol. 8, no. 12, pp. 1-8, Dec. 2013. Public Library of Science.
DOI:10.1371/journal.pone.0081499
Bibtex: BibTeX
@article{10.1371/journal.pone.0081499,
    doi = {10.1371/journal.pone.0081499},
    author = {Choi, WooJhon AND Mohler, Kathrin J. AND Potsaid, Benjamin AND Lu, Chen D. AND Liu, Jonathan J. AND Jayaraman, Vijaysekhar AND Cable, Alex E. AND Duker, Jay S. AND Huber, Robert AND Fujimoto, James G.},
    journal = {PLOS ONE},
    publisher = {Public Library of Science},
    title = {Choriocapillaris and Choroidal Microvasculature Imaging with Ultrahigh Speed OCT Angiography},
    year = {2013},
    month = {12},
    volume = {8},
    url = {https://doi.org/10.1371/journal.pone.0081499},
    pages = {1-8},
    abstract = {We demonstrate in vivo choriocapillaris and choroidal microvasculature imaging in normal human subjects using optical coherence tomography (OCT). An ultrahigh speed swept source OCT prototype at 1060 nm wavelengths with a 400 kHz A-scan rate is developed for three-dimensional ultrahigh speed imaging of the posterior eye. OCT angiography is used to image three-dimensional vascular structure without the need for exogenous fluorophores by detecting erythrocyte motion contrast between OCT intensity cross-sectional images acquired rapidly and repeatedly from the same location on the retina. En face OCT angiograms of the choriocapillaris and choroidal vasculature are visualized by acquiring cross-sectional OCT angiograms volumetrically via raster scanning and segmenting the three-dimensional angiographic data at multiple depths below the retinal pigment epithelium (RPE). Fine microvasculature of the choriocapillaris, as well as tightly packed networks of feeding arterioles and draining venules, can be visualized at different en face depths. Panoramic ultra-wide field stitched OCT angiograms of the choriocapillaris spanning ∼32 mm on the retina show distinct vascular structures at different fundus locations. Isolated smaller fields at the central fovea and ∼6 mm nasal to the fovea at the depths of the choriocapillaris and Sattler's layer show vasculature structures consistent with established architectural morphology from histological and electron micrograph corrosion casting studies. Choriocapillaris imaging was performed in eight healthy volunteers with OCT angiograms successfully acquired from all subjects. These results demonstrate the feasibility of ultrahigh speed OCT for in vivo dye-free choriocapillaris and choroidal vasculature imaging, in addition to conventional structural imaging.},
    number = {12},

}
Tianshi Wang, Wolfgang Wieser, Geert Springeling, Robert Beurskens, Charles T. Lancee, Tom Pfeiffer, Antonius F. W. van der Steen, Robert Huber, and Gijs van Soest,
Ultrahigh-speed intravascular optical coherence tomography imaging at 3200 frames per second, in Optical Coherence Tomography and Coherence Techniques VI , Brett E. Bouma and Rainer A. Leitgeb, Eds. SPIE, 062013. pp. 88020O.
DOI:10.1117/12.2032723
Bibtex: BibTeX
@inproceedings{10.1117/12.2032723,
author = {Tianshi Wang and Wolfgang Wieser and Geert Springeling and Robert Beurskens and Charles T. Lancee and Tom Pfeiffer and Antonius F. W. van der Steen and Robert Huber and Gijs van Soest},
title = {{Ultrahigh-speed intravascular optical coherence tomography imaging at 3200 frames per second}},
volume = {8802},
booktitle = {Optical Coherence Tomography and Coherence Techniques VI},
editor = {Brett E. Bouma and Rainer A. Leitgeb},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {88020O},
abstract = {We demonstrated intravascular OCT imaging with frame rate up to 3.2 kHz (192,000 rpm scanning). This was achieved by
using a custom-built catheter in which the circumferential scanning was actuated by a 1.0 mm diameter synchronous
motor. The OCT system was based on a Fourier Domain Mode Locked laser operating at an A-line rate of 1.6 MHz. The
diameter of the catheter was 1.1 mm at the tip. Ex vivo images of human coronary artery (~78.4 mm length) were acquired
at a pullback speed of 100 mm/s. True 3D volumetric imaging of the entire artery, with adequate sampling in all
dimensions, was performed in < 1 second acquisition time.},
year = {2013},
doi = {10.1117/12.2032723},
URL = {https://doi.org/10.1117/12.2032723}
}
Sebastian Karpf, Matthias Eibl, Wolfgang Wieser, Thomas Klein, and Robert Huber,
FDML Raman: High Speed, High Resolution Stimulated Raman Spectroscopy with Rapidly Wavelength Swept Lasers, in CLEO: 2013 , Optica Publishing Group, 062013. pp. CTu2H.5.
DOI:10.1364/CLEO_SI.2013.CTu2H.5
Bibtex: BibTeX
@inproceedings{Karpf:13,
author = {Sebastian Karpf and Matthias Eibl and Wolfgang Wieser and Thomas Klein and Robert Huber},
booktitle = {CLEO: 2013},
journal = {CLEO: 2013},
keywords = {Lasers, fiber; Scattering, stimulated Raman; Spectroscopy, Raman; Fourier domain mode locking; Lasers; Optical coherence tomography; Raman lasers; Raman spectroscopy; Swept lasers},
pages = {CTu2H.5},
publisher = {Optica Publishing Group},
title = {FDML Raman: High Speed, High Resolution Stimulated Raman Spectroscopy with Rapidly Wavelength Swept Lasers},
year = {2013},
url = {https://opg.optica.org/abstract.cfm?URI=CLEO_SI-2013-CTu2H.5},
doi = {10.1364/CLEO_SI.2013.CTu2H.5},
abstract = {An all fiber based system for high speed, high resolution Raman sensing is presented. The system is based on a wavelength swept Fourier Domain Mode Locked (FDML) laser for the detection of the Raman signal.},
}
Christoph M. Eigenwillig, Wolfgang Wieser, Sebastian Todor, Benjamin R. Biedermann, Thomas Klein, Christian Jirauschek, and Robert Huber,
Picosecond pulses from wavelength-swept continuous-wave Fourier domain mode-locked lasers, Nature communications , vol. 4, pp. 1848-1855, 05 2013.
DOI:10.1038/ncomms2870
Bibtex: BibTeX
@Article{HU_2013_Eigenwillig_b,
  Title                    = {{Picosecond pulses from wavelength-swept continuous-wave Fourier domain mode-locked lasers}},
  Author                   = {Eigenwillig, Christoph M and Wieser, Wolfgang and Todor, Sebastian and Biedermann, Benjamin R and Klein, Thomas and Jirauschek, Christian and Huber, Robert},
  Journal                  = {Nature communications},
  Year                     = {2013},
  Month                    = jan,
  Pages                    = {1848--1855},
  Volume                   = {4},
  Doi                      = {10.1038/ncomms2870},
  ISSN                     = {2041-1723},
keywords = {AG-Huber_FDML, AG-Huber_OCT},
  Url                      = {http://www.nature.com/ncomms/journal/v4/n5/abs/ncomms2870.html}
}
Sebastian Karpf, Matthias Eibl, Wolfgang Wieser, Thomas Klein, and Robert Huber,
FDML Raman: New High Resolution SRS with ultra broadband spectral coverage, in 2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC , 052013. pp. 1.
DOI:10.1109/CLEOE-IQEC.2013.6801995
Bibtex: BibTeX
@INPROCEEDINGS{6801995,
  author={Karpf, Sebastian and Eibl, Matthias and Wieser, Wolfgang and Klein, Thomas and Huber, Robert},
  booktitle={2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC}, 
  title={FDML Raman: New high resolution SRS with ultra broadband spectral coverage}, 
  year={2013},
  volume={},
  number={},
  pages={1-1},
  doi={10.1109/CLEOE-IQEC.2013.6801995}}
Christoph M. Eigenwillig, Sebastian Todor, Wolfgang Wieser, Benjamin R. Biedermann, Thomas Klein, Christian Jirauschek, and Robert Huber,
Picosecond pulses from a Fourier domain mode locked (FDML) laser, in 2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC , 052013. pp. 1.
DOI:10.1109/CLEOE-IQEC.2013.6801076
Bibtex: BibTeX
@INPROCEEDINGS{6801076,
  author={Eigenwillig, Christoph M. and Todor, Sebastian and Wieser, Wolfgang and Biedermann, Benjamin R. and Klein, Thomas and Jirauschek, Christian and Huber, Robert},
  booktitle={2013 Conference on Lasers & Electro-Optics Europe & International Quantum Electronics Conference CLEO EUROPE/IQEC}, 
  title={Picosecond pulses from a Fourier domain mode locked (FDML) laser}, 
  year={2013},
  volume={},
  number={},
  pages={1-1},
  doi={10.1109/CLEOE-IQEC.2013.6801076}}
Tianshi Wang, Wolfgang Wieser, Geert Springeling, Robert Beurskens, Charles T. Lancee, Tom Pfeiffer, Antonius F. W. van der Steen, Robert Huber, and Gijs van Soest,
Intravascular optical coherence tomography imaging at 3200 frames per second, Opt. Lett. , vol. 38, no. 10, pp. 1715-1717, 05 2013. Optica Publishing Group.
DOI:10.1364/OL.38.001715
Bibtex: BibTeX
@article{Wang:13,
author = {Tianshi Wang and Wolfgang Wieser and Geert Springeling and Robert Beurskens and Charles T. Lancee and Tom Pfeiffer and Antonius F. W. van der Steen and Robert Huber and Gijs van Soest},
journal = {Opt. Lett.},
keywords = {Optical coherence tomography; Endoscopic imaging; Endoscopic imaging; Fourier domain mode locking; Image quality; Laser modes; Optical coherence tomography; Three dimensional imaging},
number = {10},
pages = {1715--1717},
publisher = {Optica Publishing Group},
title = {Intravascular optical coherence tomography imaging at 3200 frames per second},
volume = {38},
month = {May},
year = {2013},
url = {https://opg.optica.org/ol/abstract.cfm?URI=ol-38-10-1715},
doi = {10.1364/OL.38.001715},
abstract = {We demonstrate intravascular optical coherence tomography (OCT) imaging with frame rate up to 3.2\&\#xA0;kHz (192,000\&\#xA0;rpm scanning). This was achieved by using a custom-built catheter in which the circumferential scanning was actuated by a 1.0\&\#xA0;mm diameter synchronous motor. The OCT system, with an imaging depth of 3.7\&\#xA0;mm (in air), is based on a Fourier domain mode locked laser operating at an A-line rate of 1.6\&\#xA0;MHz. The diameter of the catheter is 1.1\&\#xA0;mm at the tip. Ex vivo images of human coronary artery (78.4\&\#xA0;mm length) were acquired at a pullback speed of 100\&\#x2009;\&\#x2009;mm/s. True 3D volumetric imaging of the entire artery, with dense and isotropic sampling in all dimensions, was performed in \<1 second acquisition time.},
}
Thomas Klein, Raphael André, Wolfgang Wieser, Tom Pfeiffer, and Robert Huber,
Joint aperture detection for speckle reduction and increased collection efficiency in ophthalmic MHz OCT, Biomed. Opt. Express , vol. 4, no. 4, pp. 619-634, 04 2013. Optica Publishing Group.
DOI:10.1364/BOE.4.000619
Bibtex: BibTeX
@article{Klein:13,
author = {Thomas Klein and Raphael Andr\'{e} and Wolfgang Wieser and Tom Pfeiffer and Robert Huber},
journal = {Biomed. Opt. Express},
keywords = {Speckle; Medical optics instrumentation; Medical and biological imaging; Optical coherence tomography; Functional imaging; High speed imaging; Image quality; Imaging techniques; Medical imaging; Ophthalmic imaging},
number = {4},
pages = {619--634},
publisher = {Optica Publishing Group},
title = {Joint aperture detection for speckle reduction and increased collection efficiency in ophthalmic MHz OCT},
volume = {4},
month = {Apr},
year = {2013},
url = {https://opg.optica.org/boe/abstract.cfm?URI=boe-4-4-619},
doi = {10.1364/BOE.4.000619},
abstract = {Joint-aperture optical coherence tomography (JA-OCT) is an angle-resolved OCT method, in which illumination from an active channel is simultaneously probed by several passive channels. JA-OCT increases the collection efficiency and effective sensitivity of the OCT system without increasing the power on the sample. Additionally, JA-OCT provides angular scattering information about the sample in a single acquisition, so the OCT imaging speed is not reduced. Thus, JA-OCT is especially suitable for ultra high speed in-vivo imaging. JA-OCT is compared to other angle-resolved techniques, and the relation between joint aperture imaging, adaptive optics, coherent and incoherent compounding is discussed. We present angle-resolved imaging of the human retina at an axial scan rate of 1.68 MHz, and demonstrate the benefits of JA-OCT: Speckle reduction, signal increase and suppression of specular and parasitic reflections. Moreover, in the future JA-OCT may allow for the reconstruction of the full Doppler vector and tissue discrimination by analysis of the angular scattering dependence.},
}
Yaokun Zhang, Tom Pfeiffer, Wolfgang Wieser, Marcel Weller, Robert Huber, Thomas Klenzner, Jörg Raczkowsky, and Heinz Wörn,
History compounding: a novel speckle reduction technique for OCT guided cochleostomy, in Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XVII , James G. Fujimoto and Joseph A. Izatt and Valery V. Tuchin, Eds. SPIE, 032013. pp. 85713H.
DOI:10.1117/12.2006979
Bibtex: BibTeX
@inproceedings{10.1117/12.2006979,
author = {Yaokun Zhang and Tom Pfeiffer and Wolfgang Wieser and Marcel Weller and Robert Huber and Thomas Klenzner and J{\"o}rg Raczkowsky and Heinz W{\"o}rn},
title = {{History compounding: a novel speckle reduction technique for OCT guided cochleostomy}},
volume = {8571},
booktitle = {Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XVII},
editor = {James G. Fujimoto and Joseph A. Izatt and Valery V. Tuchin},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {85713H},
abstract = {Optical coherence tomography (OCT) is a promising candidate for monitoring the bottom of the drilled channel during
cochleostomy to prevent injury to the critical structure under the bone tissue. While the thickness of the overlaying bone
tissue is changed during the drilling process, the wave front of the backscattered light is also altered, resulting in
changing speckle patterns of the observed structures in the sequential historical scans. By averaging the different patterns
in these scans, named history compounding, the speckles can be reduced and the detection of critical structure becomes
much easier. Before averaging, the refractive index of bone tissue ???????? has to be compensated so that the speckles of the
same structure in different historical scans can be aligned together. An accurate method for measuring the refractive
index n<sub>b</sub> using OCT is presented. Experiments were conducted to evaluate history compounding and the new technique
is proved to be an effective, flexible and intuitive speckle reduction technique for OCT guided cochleostomy as well as
hard tissue ablation of other kind.},
keywords = {optical coherence tomography, speckle reduction, refractive index, cochleostomy, hard tissue ablation},
year = {2013},
doi = {10.1117/12.2006979},
URL = {https://doi.org/10.1117/12.2006979}
}
Teresa Torzicky, Sebastian Marschall, Michael Pircher, Bernhard Baumann, Marco Bonesi, Stefan Zotter, Erich Götzinger, Wolfgang Trasischker, Thomas Klein, Wolfgang Wieser, Benjamin R. Biedermann, Robert Huber, Peter E. Andersen, and Christoph K. Hitzenberger,
Retinal polarization-sensitive optical coherence tomography at 1060 nm with 350 kHz A-scan rate using an Fourier domain mode locked laser, Journal of Biomedical Optics , vol. 18, no. 2, pp. 026008, 02 2013. SPIE.
DOI:10.1117/1.JBO.18.2.026008
Bibtex: BibTeX
@article{10.1117/1.JBO.18.2.026008,
author = {Teresa Torzicky and Sebastian Marschall and Michael Pircher and Bernhard Baumann and Marco Bonesi and Stefan Zotter and Erich G{\"o}tzinger and Wolfgang Trasischker and Thomas Klein and Wolfgang Wieser and Benjamin R. Biedermann and Robert A. Huber and Peter E. Andersen and Christoph K. Hitzenberger},
title = {{Retinal polarization-sensitive optical coherence tomography at 1060 nm with 350 kHz A-scan rate using an Fourier domain mode locked laser}},
volume = {18},
journal = {Journal of Biomedical Optics},
number = {2},
publisher = {SPIE},
pages = {026008},
abstract = {We present a novel, high-speed, polarization-sensitive, optical coherence tomography set-up for retinal imaging operating at a central wavelength of 1060 nm which was tested for in vivo imaging in healthy human volunteers. We use the system in combination with a Fourier domain mode locked laser with active spectral shaping which enables the use of forward and backward sweep in order to double the imaging speed without a buffering stage. With this approach and with a custom designed data acquisition system, we show polarization-sensitive imaging with an A-scan rate of 350 kHz. The acquired three-dimensional data sets of healthy human volunteers show different polarization characteristics in the eye, such as depolarization in the retinal pigment epithelium and birefringence in retinal nerve fiber layer and sclera. The increased speed allows imaging of large volumes with reduced motion artifacts. Moreover, averaging several two-dimensional frames allows the generation of high-definition B-scans without the use of an eye-tracking system. The increased penetration depth of the system, which is caused by the longer probing beam wavelength, is beneficial for imaging choroidal and scleral structures and allows automated segmentation of these layers based on their polarization characteristics.},
keywords = {Optical coherence tomography, Polarization, Birefringence, Imaging systems, Data acquisition, Image segmentation, Modulation, Mode locking, 3D acquisition, Retinal scanning},
year = {2013},
doi = {10.1117/1.JBO.18.2.026008},
URL = {https://doi.org/10.1117/1.JBO.18.2.026008}
}
Thomas Klein, Wolfgang Wieser, Lukas Reznicek, Aljoscha Neubauer, Anselm Kampik, and Robert Huber,
Multi-MHz retinal OCT, Biomed. Opt. Express , vol. 4, no. 10, pp. 1890-1908, 2013. Optica Publishing Group.
DOI:10.1364/BOE.4.001890
Bibtex: BibTeX
@article{Klein:13,
author = {Thomas Klein and Wolfgang Wieser and Lukas Reznicek and Aljoscha Neubauer and Anselm Kampik 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; Distributed Bragg reflectors; Fiber Bragg gratings; Functional imaging; Image quality; Three dimensional imaging},
number = {10},
pages = {1890--1908},
publisher = {Optica Publishing Group},
title = {Multi-MHz retinal OCT},
volume = {4},
month = {Oct},
year = {2013},
url = {https://opg.optica.org/boe/abstract.cfm?URI=boe-4-10-1890},
doi = {10.1364/BOE.4.001890},
abstract = {We analyze the benefits and problems of in vivo optical coherence tomography (OCT) imaging of the human retina at A-scan rates in excess of 1 MHz, using a 1050 nm Fourier-domain mode-locked (FDML) laser. Different scanning strategies enabled by MHz OCT line rates are investigated, and a simple multi-volume data processing approach is presented. In-vivo OCT of the human ocular fundus is performed at different axial scan rates of up to 6.7 MHz. High quality non-mydriatic retinal imaging over an ultra-wide field is achieved by a combination of several key improvements compared to previous setups. For the FDML laser, long coherence lengths and 72 nm wavelength tuning range are achieved using a chirped fiber Bragg grating in a laser cavity at 419.1 kHz fundamental tuning rate. Very large data sets can be acquired with sustained data transfer from the data acquisition card to host computer memory, enabling high-quality averaging of many frames and of multiple aligned data sets. Three imaging modes are investigated: Alignment and averaging of 24 data sets at 1.68 MHz axial line rate, ultra-dense transverse sampling at 3.35 MHz line rate, and dual-beam imaging with two laser spots on the retina at an effective line rate of 6.7 MHz.},
}

2012

Marco Bonesi, Harald Sattmann, Teresa Torzicky, Stefan Zotter, Bernhard Baumann, Michael Pircher, Erich Götzinger, Christoph M. Eigenwillig, Wolfgang Wieser, Christoph K. Hitzenberger, and Robert Huber,
High-speed polarization sensitive optical coherence tomography scan engine based on Fourier domain mode locked laser, Biomed. Opt. Express , vol. 3, no. 11, pp. 2987-3000, Nov. 2012. Optica Publishing Group.
DOI:10.1364/BOE.3.002987
Bibtex: BibTeX
@article{Bonesi:12,
author = {Marco Bonesi and Harald Sattmann and Teresa Torzicky and Stefan Zotter and Bernhard Baumann and Michael Pircher and Erich G\"{o}tzinger and Christoph Eigenwillig and Wolfgang Wieser and Robert Huber and Christoph K. Hitzenberger},
journal = {Biomed. Opt. Express},
keywords = {Optical coherence tomography; Optical diagnostics for medicine; Polarization-selective devices; High speed imaging; Image quality; Laser modes; Mode locking; Single mode fibers; Three dimensional imaging},
number = {11},
pages = {2987--3000},
publisher = {Optica Publishing Group},
title = {High-speed polarization sensitive optical coherence tomography scan engine based on Fourier domain mode locked laser},
volume = {3},
month = {Nov},
year = {2012},
url = {https://opg.optica.org/boe/abstract.cfm?URI=boe-3-11-2987},
doi = {10.1364/BOE.3.002987},
abstract = {We report on a new swept source polarization sensitive optical coherence tomography scan engine that is based on polarization maintaining (PM) fiber technology. The light source is a Fourier domain mode locked laser with a PM cavity that operates in the 1300 nm wavelength regime. It is equipped with a PM buffer stage that doubles the fundamental sweep frequency of 54.5 kHz. The fiberization allows coupling of the scan engine to different delivery probes. In a first demonstration, we use the system for imaging human skin at an A-scan rate of 109 kHz. The system illuminates the sample with circularly polarized light and measures reflectivity, retardation, optic axis orientation, and Stokes vectors simultaneously. Furthermore, depolarization can be quantified by calculating the degree of polarization uniformity (DOPU). The high scanning speed of the system enables dense sampling in both, the x- and y-direction, which provides the opportunity to use 3D evaluation windows for DOPU calculation. This improves the spatial resolution of DOPU images considerably.},
}
Cedric Blatter, Branislav Grajciar, Pu Zou, Wolfgang Wieser, Aart-Jan Verhoef, Robert Huber, and Rainer A. Leitgeb,
Intrasweep phase-sensitive optical coherence tomography for noncontact optical photoacoustic imaging, Opt. Lett. , vol. 37, no. 21, pp. 4368-4370, Nov. 2012. Optica Publishing Group.
DOI:10.1364/OL.37.004368
Bibtex: BibTeX
@article{Blatter:12,
author = {Cedric Blatter and Branislav Grajciar and Pu Zou and Wolfgang Wieser and Aart-Jan Verhoef and Robert Huber and Rainer A. Leitgeb},
journal = {Opt. Lett.},
keywords = {Optical coherence tomography; Optical coherence tomography; Photoacoustic imaging; Interferometric imaging ; Photoacoustics ; In vivo imaging; Interferometry; Linewidth; Medical imaging; Optical coherence tomography; Swept sources},
number = {21},
pages = {4368--4370},
publisher = {Optica Publishing Group},
title = {Intrasweep phase-sensitive optical coherence tomography for noncontact optical photoacoustic imaging},
volume = {37},
month = {Nov},
year = {2012},
url = {https://opg.optica.org/ol/abstract.cfm?URI=ol-37-21-4368},
doi = {10.1364/OL.37.004368},
abstract = {We introduce a method to extract the photoacoustic (PA) signal from the phase time evolution of an optical coherence tomography (OCT) swept source spectral sweep. This all-optical detection is achieved in a noncontact fashion directly on the sample surface by using its specular reflection. High-speed measurement and referencing allow for close to shot noise limited phase-sensitive detection. It offers a simple way to perform OCT and PA imaging by sharing the same system components.},
}
Cedric Blatter, Jessika Weingast, Aneesh Alex, Branislav Grajciar, Wolfgang Wieser, Wolfgang Drexler, Robert Huber, and Rainer A. Leitgeb,
In situ structural and microangiographic assessment of human skin lesions with high-speed OCT, Biomed. Opt. Express , vol. 3, no. 10, pp. 2636-2646, Oct. 2012. Optica Publishing Group.
DOI:10.1364/BOE.3.002636
Bibtex: BibTeX
@article{Blatter:12,
author = {Cedric Blatter and Jessika Weingast and Aneesh Alex and Branislav Grajciar and Wolfgang Wieser and Wolfgang Drexler and Robert Huber and Rainer A. Leitgeb},
journal = {Biomed. Opt. Express},
keywords = {Optical coherence tomography; Optical coherence tomography; Flow diagnostics; Functional monitoring and imaging ; Fourier domain mode locking; High speed imaging; Image processing; In vivo imaging; Speckle imaging; Three dimensional imaging},
number = {10},
pages = {2636--2646},
publisher = {Optica Publishing Group},
title = {In situ structural and microangiographic assessment of human skin lesions with high-speed OCT},
volume = {3},
month = {Oct},
year = {2012},
url = {https://opg.optica.org/boe/abstract.cfm?URI=boe-3-10-2636},
doi = {10.1364/BOE.3.002636},
abstract = {We demonstrate noninvasive structural and microvascular contrast imaging of different human skin diseases in vivo using an intensity difference analysis of OCT tomograms. The high-speed swept source OCT system operates at 1310 nm with 220 kHz A-scan rate. It provides an extended focus by employing a Bessel beam. The studied lesions were two cases of dermatitis and two cases of basal cell carcinoma. The lesions show characteristic vascular patterns that are significantly different from healthy skin. In case of inflammation, vessels are dilated and perfusion is increased. In case of basal cell carcinoma, the angiogram shows a denser network of unorganized vessels with large vessels close to the skin surface. Those results indicate that assessing vascular changes yields complementary information with important insight into the metabolic demand.},
}
Wolfgang Wieser, Thomas Klein, Desmond C. Adler, Francois Trepanier, Christoph M. Eigenwillig, Sebastian Karpf, Joseph M. Schmitt, and Robert Huber,
Extended coherence length megahertz FDML and its application for anterior segment imaging, Biomed. Opt. Express , vol. 3, no. 10, pp. 2647-2657, Oct. 2012. Optica Publishing Group.
DOI:10.1364/BOE.3.002647
Bibtex: BibTeX
@article{Wieser:12,
author = {Wolfgang Wieser and Thomas Klein and Desmond C. Adler and Francois Tr\'{e}panier and Christoph M. Eigenwillig and Sebastian Karpf and Joseph M. Schmitt and Robert Huber},
journal = {Biomed. Opt. Express},
keywords = {Optical coherence tomography; Lasers, tunable; Optical coherence tomography; Amplified spontaneous emission; Crystalline lens; Gastrointestinal imaging; High speed imaging; Image quality; Three dimensional imaging},
number = {10},
pages = {2647--2657},
publisher = {Optica Publishing Group},
title = {Extended coherence length megahertz FDML and its application for anterior segment imaging},
volume = {3},
month = {Oct},
year = {2012},
url = {https://opg.optica.org/boe/abstract.cfm?URI=boe-3-10-2647},
doi = {10.1364/BOE.3.002647},
abstract = {We present a 1300 nm Fourier domain mode locked (FDML) laser for optical coherence tomography (OCT) that combines both, a high 1.6 MHz wavelength sweep rate and an ultra-long instantaneous coherence length for rapid volumetric deep field imaging. By reducing the dispersion in the fiber delay line of the FDML laser, the instantaneous coherence length and hence the available imaging range is approximately quadrupled compared to previously published MHz-FDML setups, the imaging speed is increased by a factor of 16 compared to previous extended coherence length results. We present a detailed characterization of the FDML laser performance. We demonstrate for the first time MHz-OCT imaging of the anterior segment of the human eye. The OCT system provides enough imaging depth to cover the whole range from the top surface of the cornea down to the crystalline lens.},
}
Cedric Blatter, Branislav Grajciar, Tilman Schmoll, Rainer A. Leitgeb, Thomas Klein, Wolfgang Wieser, Raphael André, and Robert Huber,
Ultrahigh-speed non-invasive widefield angiography, Journal of Biomedical Optics , vol. 17, no. 7, pp. 070505, 06 2012. SPIE.
DOI:10.1117/1.JBO.17.7.070505
Bibtex: BibTeX
@article{10.1117/1.JBO.17.7.070505,
author = {Cedric Blatter and Branislav Grajciar and Tilman Schmoll and Rainer A. Leitgeb and Thomas Klein and Wolfgang Wieser and Raphael J. Andr{\'e} and Robert Huber},
title = {{Ultrahigh-speed non-invasive widefield angiography}},
volume = {17},
journal = {Journal of Biomedical Optics},
number = {7},
publisher = {SPIE},
pages = {070505},
abstract = {Retinal and choroidal vascular imaging is an important diagnostic benefit for ocular diseases such as age-related macular degeneration. The current gold standard for vessel visualization is fluorescence angiography. We present a potential non-invasive alternative to image blood vessels based on functional Fourier domain optical coherence tomography (OCT). For OCT to compete with the field of view and resolution of angiography while maintaining motion artifacts to a minimum, ultrahigh-speed imaging has to be introduced. We employ Fourier domain mode locking swept source technology that offers high quality imaging at an A-scan rate of up to 1.68 MHz. We present retinal angiogram over ∼ 48  deg acquired in a few seconds in a single recording without the need of image stitching. OCT at 1060 nm allows for high penetration in the choroid and efficient separate characterization of the retinal and choroidal vascularization.},
keywords = {Angiography, Optical coherence tomography, Image segmentation, Retina, Capillaries, Tissues, Visualization, Diagnostics, Gold, Vascular imaging},
year = {2012},
doi = {10.1117/1.JBO.17.7.070505},
URL = {https://doi.org/10.1117/1.JBO.17.7.070505}
}
Sebastian Marschall, Teresa Torzicky, Thomas Klein, Wolfgang Wieser, Michael Pircher, Erich Götzinger, Stefan Zotter, Marco Bonesi, Benjamin R. Biedermann, Christian Pedersen, Robert Huber, Christoph K. Hitzenberger, and Peter E. Andersen,
High-speed polarization-sensitive OCT at 1060 nm using a Fourier domain mode-locked swept source, in Biophotonics: Photonic Solutions for Better Health Care III , Jürgen Popp and Wolfgang Drexler and Valery V. Tuchin and Dennis L. Matthews, Eds. SPIE, 052012. pp. 84271D.
DOI:10.1117/12.922313
Bibtex: BibTeX
@inproceedings{10.1117/12.922313,
author = {Sebastian Marschall and Teresa Torzicky and Thomas Klein and Wolfgang Wieser and Michael Pircher and Erich G{\"o}tzinger and Stefan Zotter and Marco Bonesi and Benjamin Biedermann and Christian Pedersen and Robert Huber and Christoph Hitzenberger and Peter Andersen},
title = {{High-speed polarization-sensitive OCT at 1060 nm using a Fourier domain mode-locked swept source}},
volume = {8427},
booktitle = {Biophotonics: Photonic Solutions for Better Health Care III},
editor = {J{\"u}rgen Popp and Wolfgang Drexler and Valery V. Tuchin and Dennis L. Matthews},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {84271D},
abstract = {Optical coherence tomography (OCT) in the 1060nm range is interesting for in vivo imaging of the human
posterior eye segment (retina, choroid, sclera), as it permits a long penetration depth. Complementary to
structural images, polarization-sensitive OCT (PS-OCT) images visualize birefringent, polarization-maintaining
or depolarizing areas within the sample. This information can be used to distinguish retinal layers and structures
with different polarization properties. High imaging speed is crucial for imaging ocular structures in vivo in order
to minimize motion artifacts while acquiring sufficiently large datasets. Here, we demonstrate PS-OCT imaging
at 350 kHz A-scan rate using a two-channel PS-OCT system in conjunction with a Fourier domain mode-locked
laser. The light source spectrum spans up to 100nm around the water absorption minimum at 1060 nm. By
modulating the laser pump current, we can optimize the spectrum and achieve a depth resolution of 9 &mu;m in air
(6.5 &mu;m in tissue). We acquired retinal images in vivo with high resolution and deep penetration into choroid and
sclera, and features like the depolarizing RPE or an increasing phase retardation at the chorio-scleral interface
are clearly visualized.},
keywords = {optical coherence tomography, polarization-sensitive OCT, swept source, Fourier domain mode-locking, 1060 nm},
year = {2012},
doi = {10.1117/12.922313},
URL = {https://doi.org/10.1117/12.922313}
}
Wolfgang Wieser, Thomas Klein, Desmond C. Adler, Francois Trepanier, Sebastian Karpf, Christoph M. Eigenwillig, Joseph M. Schmitt, and Robert Huber,
Dispersion Compensated Megahertz FDML Laser for Imaging of the Anterior Segment, in Conference on Lasers and Electro-Optics 2012 , Optica Publishing Group, 052012. pp. JTh3J.2.
DOI:10.1364/CLEO_AT.2012.JTh3J.2
Bibtex: BibTeX
@inproceedings{Wieser:12,
author = {Wolfgang Wieser and Thomas Klein and Desmond C. Adler and Francois Tr\'{e}panier and Sebastian Karpf and Christoph M Eigenwillig and Joseph M. Schmitt and Robert Huber},
booktitle = {Conference on Lasers and Electro-Optics 2012},
journal = {Conference on Lasers and Electro-Optics 2012},
keywords = {Optical coherence tomography; Lasers, tunable; Optical coherence tomography; Fiber Bragg gratings; Fourier domain mode locking; Image quality; Laser modes; Mode locking; Optical coherence tomography},
pages = {JTh3J.2},
publisher = {Optica Publishing Group},
title = {Dispersion Compensated Megahertz FDML Laser for Imaging of the Anterior Segment},
year = {2012},
url = {https://opg.optica.org/abstract.cfm?URI=CLEO_AT-2012-JTh3J.2},
doi = {10.1364/CLEO_AT.2012.JTh3J.2},
abstract = {We present a Fourier domain mode locked laser at 1.6 MHz scan rate with greatly improved coherence length by reducing the laser cavity dispersion and the application of this laser in optical coherence tomography.},
}
Wolfgang Wieser, Gesa Palte, Christoph M. Eigenwillig, Benjamin R. Biedermann, Tom Pfeiffer, and Robert Huber,
Chromatic polarization effects of swept waveforms in FDML lasers and fiber spools, Optics Express , vol. 20, no. 9, pp. 9819-9832, 04 2012. Optica Publishing Group.
DOI:10.1364/OE.20.009819
Bibtex: BibTeX
@Article{HU_2012_Wieser_a,
  Title                    = {{Chromatic polarization effects of swept waveforms in FDML lasers and fiber spools}},
  Author                   = {Wieser, Wolfgang and Palte, Gesa and Eigenwillig, Christoph M and Biedermann, Benjamin R and Pfeiffer, Tom and Huber, Robert},
  Journal                  = {Optics express},
  Year                     = {2012},

  Month                    = apr,
  Number                   = {9},
  Pages                    = {9819--32},
  Volume                   = {20},

  Doi                      = {10.1364/OE.20.009819},
  ISSN                     = {1094-4087},
keywords = {AG-Huber_FDML, AG-Huber_OCT},
  Url                      = {http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-20-9-9819\&id=231991}
}
Sebastian Todor, Robert Huber, Benjamin R. Biedermann, and Christian Jirauschek,
Balance of physical effects causing stationary operation of Fourier domain mode-locked lasers, J. Opt. Soc. Am. B , vol. 29, no. 4, pp. 656-664, 04 2012. Optica Publishing Group.
DOI:10.1364/JOSAB.29.000656
Bibtex: BibTeX
@article{Todor:12,
author = {Sebastian Todor and Benjamin Biedermann and Robert Huber and Christian Jirauschek},
journal = {J. Opt. Soc. Am. B},
keywords = {Laser theory; Lasers, tunable; Optical coherence tomography; Mode locking; Numerical simulation; Optical amplifiers; Power spectra; Swept lasers; Tunable lasers},
number = {4},
pages = {656--664},
publisher = {Optica Publishing Group},
title = {Balance of physical effects causing stationary operation of Fourier domain mode-locked lasers},
volume = {29},
month = {Apr},
year = {2012},
url = {https://opg.optica.org/josab/abstract.cfm?URI=josab-29-4-656},
doi = {10.1364/JOSAB.29.000656},
abstract = {We present a detailed analysis of the optical field dynamics in a Fourier domain mode-locked (FDML) laser. We employ a numerical simulation based on the FDML evolution equation, describing the propagation of the optical light field. The temporal evolution of the instantaneous power spectrum at different points in the laser cavity is investigated. The results are carefully validated against experimental data, yielding good agreement. Deeper insight is gained into the role of the physical effects governing FDML dynamics, such as gain recovery and linewidth enhancement in the semiconductor optical amplifier, dispersion and self-phase modulation in the optical fiber, and the sweep filter action.},
}
Thomas Klein, Wolfgang Wieser, Raphael André, Tom Pfeiffer, Christoph M. Eigenwillig, and Robert Huber,
Multi-MHz FDML OCT: snapshot retinal imaging at 6.7 million axial-scans per second, in Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XVI , Joseph A. Izatt and James G. Fujimoto and Valery V. Tuchin, Eds. SPIE, 022012. pp. 82131E.
DOI:10.1117/12.908798
Bibtex: BibTeX
@inproceedings{10.1117/12.908798,
author = {Thomas Klein and Wolfgang Wieser and Raphael Andr{\'e} and Tom Pfeiffer and Christoph M. Eigenwillig and Robert Huber},
title = {{Multi-MHz FDML OCT: snapshot retinal imaging at 6.7 million axial-scans per second}},
volume = {8213},
booktitle = {Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XVI},
editor = {Joseph A. Izatt and James G. Fujimoto and Valery V. Tuchin},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {82131E},
abstract = {We demonstrate the acquisition of densely sampled wide-field 3D OCT datasets of the human retina in 0.3s. This
performance is achieved with a multi-MHz Fourier domain mode-locked (FDML) laser source operating at 1050nm. A two-beam
setup doubles the 3.35MHz laser sweep rate to 6.7MHz, which is 16x faster than results achieved with any non-FDML
source used for retinal OCT. We discuss two main benefits of these high line rates: First, large datasets over an ultra-wide
field of view can be acquired with a low probability of distortions. Second, even if eye movements occur, now the scan rate
is high enough to directly correct even the fastest saccades without loss of information.},
keywords = {Optical coherence tomography, OCT, MHz OCT, Fourier-domain mode-locking, FDML, retinal imaging},
year = {2012},
doi = {10.1117/12.908798},
URL = {https://doi.org/10.1117/12.908798}
}

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