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

2009

Evelyn Ploetz, Berit Marx, Thomas Klein, Robert Huber, and Peter Gilch,
A 75 MHz light source for femtosecond stimulated raman microscopy, Opt. Express , vol. 17, no. 21, pp. 18612-18620, Oct. 2009. Optica Publishing Group.
DOI:10.1364/OE.17.018612
Bibtex: BibTeX
@article{Ploetz:09,
author = {E. Ploetz and B. Marx and T. Klein and R. Huber and P. Gilch},
journal = {Opt. Express},
keywords = {Laser amplifiers; Ultrafast lasers; Nonlinear microscopy; Raman microscopy; Laser sources; Raman microscopy; Raman scattering; Raman spectroscopy; Stimulated Raman scattering; Time resolved spectroscopy},
number = {21},
pages = {18612--18620},
publisher = {Optica Publishing Group},
title = {A 75 MHz Light Source for Femtosecond Stimulated Raman Microscopy},
volume = {17},
month = {Oct},
year = {2009},
url = {https://opg.optica.org/oe/abstract.cfm?URI=oe-17-21-18612},
doi = {10.1364/OE.17.018612},
abstract = {In femtosecond stimulated Raman microscopy (FSRM) a spectrally broad pulse (Raman probe) and a spectrally narrow pulse (Raman pump) interact in a sample and thereby generate a Raman spectrum of the focal volume. Here a novel light source for FSRM is presented. It consists of an 8-fs laser (repetition rate of 75 MHz) operating as Raman probe. A Yb3$+$ based fiber amplifier generates the Raman pump light at 980 nm. The amplifier is seeded by the spectral wing of the 8-fs laser output which ensures synchronisation of pump and probe pulses. Spectral and temporal characteristics of these pulses are reported and simultaneous recording of broadband Raman spectra relying on these pulses is demonstrated.},
}
Rainer Leonhardt, Benjamin R. Biedermann, Wolfgang Wieser, and Robert Huber,
Nonlinear optical frequency conversion of an amplified Fourier Domain Mode Locked (FDML) laser., Opt. Express , vol. 17, no. 19, pp. 16801-16808, 09 2009. Optica Publishing Group.
DOI:10.1364/OE.17.016801
Bibtex: BibTeX
@article{Leonhardt:09,
author = {Rainer Leonhardt and Benjamin R. Biedermann and Wolfgang Wieser and Robert Huber},
journal = {Opt. Express},
keywords = {Fiber optics amplifiers and oscillators; Fibers, erbium; Lasers, tunable; Nonlinear optics, fibers; Nonlinear optics, four-wave mixing; Wavelength conversion devices ; Four wave mixing; Fourier domain mode locking; Laser sources; Optical coherence tomography; Optical frequency conversion; Semiconductor optical amplifiers},
number = {19},
pages = {16801--16808},
publisher = {Optica Publishing Group},
title = {Nonlinear optical frequency conversion of an amplified Fourier Domain Mode Locked (FDML) laser},
volume = {17},
month = {Sep},
year = {2009},
url = {https://opg.optica.org/oe/abstract.cfm?URI=oe-17-19-16801},
doi = {10.1364/OE.17.016801},
abstract = {We report on the highly efficient non-linear optical frequency conversion of the wavelength swept output from a Fourier Domain Mode Locked (FDML) laser. Different concepts for power scaling of FDML lasers by post-amplification with active fibers are presented. A two-stage post-amplification of an FDML laser with an amplification factor of 300 up to a peak power of 1.5 W is used to supply sufficient power levels for non-linear conversion. Using a single-mode dispersion shifted fiber (DSF), we convert this amplified output that covers the region between 1541 nm and 1545 nm to a wavelength range from 1572 nm to 1663 nm via modulation instability (MI). For this four wave mixing process we observe an efficiency of ~40\%. The anti-Stokes signal between 1435 nm and 1516 nm was observed with lower conversion efficiency. In addition to shifting the wavelength, the effect of MI also enables a substantial increase in the wavelength sweep rate of the FDML laser by a factor of ~50 to 0.55 nm/ns.},
}
Michalina Gora, Karol Karnowski, Maciej Szkulmowski, Bartlomiej Kaluzny, Robert Huber, Andrzej M. Kowalczyk, and Maciej Wojtkowski,
Ultra high-speed swept source OCT imaging of the anterior segment of human eye at 200 kHz with adjustable imaging range, Opt. Express , vol. 17, no. 17, pp. 14880-14894, 08 2009. Optica Publishing Group.
DOI:10.1364/OE.17.014880
Bibtex: BibTeX
@article{Gora:09,
author = {Michalina Gora and Karol Karnowski and Maciej Szkulmowski and Bartlomiej J. Kaluzny and Robert Huber and Andrzej Kowalczyk and Maciej Wojtkowski},
journal = {Opt. Express},
keywords = {Optical coherence tomography; Lasers, tunable; Ophthalmology; Crystalline lens; High speed imaging; Imaging systems; Ophthalmic imaging; Optical coherence tomography; Three dimensional imaging},
number = {17},
pages = {14880--14894},
publisher = {Optica Publishing Group},
title = {Ultra high-speed swept source OCT imaging of the anterior segment of human eye at 200 kHz with adjustable imaging range},
volume = {17},
month = {Aug},
year = {2009},
url = {https://opg.optica.org/oe/abstract.cfm?URI=oe-17-17-14880},
doi = {10.1364/OE.17.014880},
abstract = {We present an application of in vivo anterior segment imaging of the human eye with an ultrahigh speed swept source OCT instrument. For this purpose, a dedicated OCT system was designed and constructed. This instrument enables axial zooming by automatic reconfiguration of spectral sweep range; an enhanced imaging range mode enables imaging of the entire anterior segment while a high axial resolution mode provides detailed morphological information of the chamber angle and the cornea. The speed of 200,000 lines/s enables high sampling density in three-dimensional imaging of the entire cornea in 250 ms promising future applications of OCT for optical corneal topography, pachymetry and elevation maps. The results of a preliminary quantitative corneal analysis based on OCT data free form motion artifacts are presented. Additionally, a volumetric and real time reconstruction of dynamic processes, like pupillary reaction to light stimulus or blink-induced contact lens movements are demonstrated.},
}
Gesa Palte, Wolfgang Wieser, Benjamin R. Biedermann, Christoph M. Eigenwillig, and Robert Huber,
Fourier domain mode locked (FDML) lasers for polarization sensitive OCT, in Optical Coherence Tomography and Coherence Techniques IV , Peter E. Andersen and Brett E. Bouma, Eds. SPIE, 072009. pp. 73720M.
DOI:10.1117/12.831835
Bibtex: BibTeX
@inproceedings{10.1117/12.831835,
author = {Gesa Palte and Wolfgang Wieser and Benjamin R. Biedermann and Christoph M. Eigenwillig and Robert Huber},
title = {{Fourier domain mode locked (FDML) lasers for polarization sensitive OCT}},
volume = {7372},
booktitle = {Optical Coherence Tomography and Coherence Techniques IV},
editor = {Peter E. Andersen and Brett E. Bouma},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {73720M},
abstract = {A Fourier Domain mode-locked (FDML) laser for polarization sensitive optical coherence tomography (OCT) is
presented. The laser generates an alternating sequence of wavelength sweeps with their polarization states 90° separated
on the Poincare sphere.},
keywords = {Lasers, tunable, optical coherence tomography, lasers, imaging systems, polarization, fiber},
year = {2009},
doi = {10.1117/12.831835},
URL = {https://doi.org/10.1117/12.831835}
}
Christoph M. Eigenwillig, Benjamin R. Biedermann, Wolfgang Wieser, and Robert Huber,
Wavelength swept ASE source, in Optical Coherence Tomography and Coherence Techniques IV , Peter E. Andersen and Brett E. Bouma, Eds. SPIE, 072009. pp. 73720O.
DOI:10.1117/12.831831
Bibtex: BibTeX
@inproceedings{10.1117/12.831831,
author = {Christoph M. Eigenwillig and Benjamin R. Biedermann and Wolfgang Wieser and Robert Huber},
title = {{Wavelength swept ASE source}},
volume = {7372},
booktitle = {Optical Coherence Tomography and Coherence Techniques IV},
editor = {Peter E. Andersen and Brett E. Bouma},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {73720O},
abstract = {We present a novel wavelength swept light source for Optical Coherence Tomography (OCT). Arbitrary sweep rates up
to 2x170kHz are achieved by phase-shifted control of two optical bandpass-filters to compensate light propagation
effects.},
keywords = {amplified spontaneous emission, tunable lasers, lasers, optical coherence tomography, optical frequency domain imaging},
year = {2009},
doi = {10.1117/12.831831},
URL = {https://doi.org/10.1117/12.831831}
}
Benjamin R. Biedermann, Wolfgang Wieser, Christoph M. Eigenwillig, and Robert Huber,
Recent developments in Fourier domain mode locked lasers for optical coherence tomography: imaging at 1310 nm vs. 1550 nm wavelength, Journal of Biophotonics , vol. 2, no. 6-7, pp. 357-363, 07 2009.
DOI:10.1002/jbio.200910028
Bibtex: BibTeX
@article{https://doi.org/10.1002/jbio.200910028,
author = {Biedermann, Benjamin R. and Wieser, Wolfgang and Eigenwillig, Christoph M. and Huber, Robert},
title = {Recent developments in Fourier Domain Mode Locked lasers for optical coherence tomography: Imaging at 1310 nm vs. 1550 nm wavelength},
journal = {Journal of Biophotonics},
volume = {2},
number = {6-7},
pages = {357-363},
keywords = {optical coherence tomography, tunable lasers, Fourier domain mode locking, optical frequency domain imaging},
doi = {https://doi.org/10.1002/jbio.200910028},
url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/jbio.200910028},
eprint = {https://onlinelibrary.wiley.com/doi/pdf/10.1002/jbio.200910028},
abstract = {Abstract We report on recent progress in Fourier domain mode-locking (FDML) technology. The paper focuses on developments beyond pushing the speed of these laser sources. After an overview of improvements to FDML over the last three years, a brief analysis of OCT imaging using FDML lasers with different wavelengths is presented. For the first time, high speed, high quality FDML imaging at 1550 nm is presented and compared to a system at 1310 nm. The imaging results of human skin for both wavelengths are compared and analyzed. Sample arm optics, power on the sample, heterodyne gain, detection bandwidth, colour cut levels and sample location have been identical to identify the influence of difference in scattering and water absorption. The imaging performance at 1310 nm in human skin is only slightly better and the results suggest that water absorption only marginally affects the penetration depth in human skin at 1550 nm. For several applications this wavelength may be preferred. (© 2009 WILEY-VCH Verlag GmbH \& Co. KGaA, Weinheim)},
year = {2009}
}
Benjamin R. Biedermann, Wolfgang Wieser, Christoph M. Eigenwillig, Thomas Klein, and Robert Huber,
Dispersion, coherence and noise of Fourier Domain Mode Locked (FDML) lasers, in CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference , IEEE, 062009. pp. 1-1.
DOI:10.1109/CLEOE-EQEC.2009.5192900
Bibtex: BibTeX
@INPROCEEDINGS{5192900,
  author={Biedermann, Benjamin R. and Wieser, Wolfgang and Eigenwillig, Christoph M. and Klein, Thomas and Huber, Robert},
  booktitle={CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference}, 
  title={Dispersion, coherence and noise of Fourier Domain Mode Locked (FDML) lasers}, 
  year={2009},
  volume={},
  number={},
  pages={1-1},
  abstract={We present a detailed analysis of coherence and noise of the FDML laser, depending on filter drive frequency, detuning and amount of cavity dispersion. The results provide insight into phase and amplitude noise of the laser light itself. We address the following two questions: (1) How much dispersion compensation is necessary for optimum laser performance in FDML for a certain width of the optical band pass filter? (2) How are timing mismatch effects, caused by either detuning of the drive frequency or chromatic dispersion in the cavity of the filter, related to coherence length and noise?},
  keywords={},
  doi={10.1109/CLEOE-EQEC.2009.5192900},
  ISSN={},
  month={June},}
Robert Huber,
State-of-the-art and future of ultrahigh speed OCT, in CLEO/Europe and EQEC 2009 Conference Digest , Optica Publishing Group, 062009. pp. JTuA_3.
DOI:10.1109/CLEOE-EQEC.2009.5191695
Bibtex: BibTeX
@INPROCEEDINGS{5191695,
  author={Huber, Robert},
  booktitle={CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference}, 
  title={State-of-the-art and future of ultrahigh speed OCT}, 
  year={2009},
  volume={},
  number={},
  pages={1-1},
  abstract={This paper reviews the current status of high speed OCT systems on the different levels of development: commercial, laboratory prototype style and proof of concept type systems. The pro and contra of SD-OCT and SS-OCT are discussed and an analysis of the desired optimum imaging speeds for various applications. SS-OCT systems are used for imaging in highly scattering tissue ~1300 nm, a line rate of 60 MHz was achieved by with SD-OCT.},
  keywords={},
  doi={10.1109/CLEOE-EQEC.2009.5191695},
  ISSN={},
  month={June},}
Benjamin R. Biedermann, Wolfgang Wieser, Christoph M. Eigenwillig, Thomas Klein, and Robert Huber,
Dispersion, coherence and noise of Fourier domain mode locked lasers, Opt. Express , vol. 17, no. 12, pp. 9947-9961, 05 2009. Optica Publishing Group.
DOI:10.1364/OE.17.009947
Bibtex: BibTeX
@article{Biedermann:09,
author = {Benjamin R. Biedermann and Wolfgang Wieser and Christoph M. Eigenwillig and Thomas Klein and Robert Huber},
journal = {Opt. Express},
keywords = {Noise in imaging systems; Optical coherence tomography; Interferometry; Lasers, tunable; Optical coherence tomography; Dispersion; Laser light; Laser modes; Laser operation; Laser sources; Mode locking; Swept lasers},
number = {12},
pages = {9947--9961},
publisher = {Optica Publishing Group},
title = {Dispersion, coherence and noise of Fourier domain mode locked lasers},
volume = {17},
month = {Jun},
year = {2009},
url = {https://opg.optica.org/oe/abstract.cfm?URI=oe-17-12-9947},
doi = {10.1364/OE.17.009947},
abstract = {We report on the effect of chromatic dispersion on coherence length and noise of Fourier Domain Mode Locked (FDML) lasers. An FDML laser with a sweep range of 100nm around 1550nm has been investigated. Cavity configurations with and without dispersion compensation have been analyzed using different widths of the intra-cavity optical band-pass filter. The measurements are compared to non-FDML wavelength swept laser sources. Based on these observations, a simple model is developed providing a connection between timing, photon cavity lifetime and characteristic time constant of the filter. In an optimized configuration, an instantaneous laser linewidth of 20pm is observed, corresponding to a 10{\texttimes} narrowing compared to the intra-cavity optical band-pass filter. A relative intensity noise of -133dBc/Hz or 0.2\% at 100MHz detection bandwidth during sweep operation is observed. For optimum operation, the filter drive frequency has to be set within 2ppm or 120mHz at 51kHz.},
}
Thomas Klein, Wolfgang Wieser, Benjamin R. Biedermann, Christoph M. Eigenwillig, Gesa Palte, and Robert Huber,
Raman pumped Fourier Domain Mode Locked (FDML) laser: Analysis of operation and application for optical coherence tomography (OCT), in CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference , IEEE, 052009. pp. 1-1.
DOI:10.1109/CLEOE-EQEC.2009.5194704
Bibtex: BibTeX
@INPROCEEDINGS{5194704,
  author={Klein, Thomas and Wieser, Wolfgang and Biedermann, Benjamin R. and Eigenwillig, Christoph M. and Palte, Gesa and Huber, Robert},
  booktitle={CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference}, 
  title={Raman pumped Fourier Domain Mode Locked (FDML) laser: Analysis of operation and application for optical coherence tomography (OCT)}, 
  year={2009},
  volume={},
  number={},
  pages={1-1},
  abstract={limitations of the sweep repetition rate of rapidly wavelength swept laser sources. Such sources can be applied for optical coherence tomography (OCT) using frequency domain detection. This technique is called swept source OCT (ss-OCT) or optical frequency domain imaging (OFDI). FDML lasers usually consist of a semiconductor optical amplifier (SOA) as laser gain medium, an output coupler, a periodically driven optical band-pass filter (FFP-TF) and an optical delay line, so that their total length is typically several kilometres.},
  keywords={},
  doi={10.1109/CLEOE-EQEC.2009.5194704},
  ISSN={},
  month={June},}
Christoph M. Eigenwillig, Wolfgang Wieser, Benjamin R. Biedermann, and Robert Huber,
Subharmonic Fourier domain mode locking, Opt. Lett. , vol. 34, no. 6, pp. 725-727, 03 2009. Optica Publishing Group.
DOI:10.1364/OL.34.000725
Bibtex: BibTeX
@article{Eigenwillig:09,
author = {Christoph M. Eigenwillig and Wolfgang Wieser and Benjamin R. Biedermann and Robert Huber},
journal = {Opt. Lett.},
keywords = {Coherence imaging; Optical coherence tomography; Three-dimensional image acquisition; Lasers, tunable; Medical and biological imaging; Optical coherence tomography; Fourier domain mode locking; Laser operation; Laser sources; Laser systems; Mode locking; Optical coherence tomography},
number = {6},
pages = {725--727},
publisher = {Optica Publishing Group},
title = {Subharmonic Fourier domain mode locking},
volume = {34},
month = {Mar},
year = {2009},
url = {https://opg.optica.org/ol/abstract.cfm?URI=ol-34-6-725},
doi = {10.1364/OL.34.000725},
abstract = {We demonstrate a subharmonically Fourier domain mode-locked wavelength-swept laser source with a substantially reduced cavity fiber length. In contrast to a standard Fourier domain mode-locked configuration, light is recirculated repetitively in the delay line with the optical bandpass filter used as switch. The laser has a fundamental optical round trip frequency of 285 kHz and can be operated at integer fractions thereof (subharmonics). Sweep ranges up to 95 nm full width centred at 1317 nm are achieved at the 1/5th subharmonic. A maximum sensitivity of 116 dB and an axial resolution of 12 $\mu$m in air are measured at an average sweep power of 12 mW. A sensitivity roll-off of 11 dB over 4 mm and 25 dB over 10 mm is observed and optical coherence tomography imaging is demonstrated. Besides the advantage of a reduced fiber length, subharmonic Fourier domain mode locking (shFDML) enables simple scaling of the sweep speed by extracting light from the delay part of the resonator. A sweep rate of 570 kHz is achieved. Characteristic features of shFDML operation, such as power leakage during fly-back and cw breakthrough, are investigated.},
}
Karol Karnowski, Michalina Gora, Bartlomiej Kaluzny, Robert Huber, Maciej Szkulmowski, Andrzej M. Kowalczyk, and Maciej Wojtkowski,
Swept source OCT imaging of human anterior segment at 200 kHz, in Ophthalmic Technologies XIX , Fabrice Manns and Per G. Söderberg and Arthur Ho, Eds. SPIE, 022009. pp. 716308.
DOI:10.1117/12.808555
Bibtex: BibTeX
@inproceedings{10.1117/12.808555,
author = {Karol Karnowski and Michalina Gora and Bartlomiej Kaluzny and Robert Huber and Maciej Szkulmowski and Andrzej Kowalczyk and Maciej Wojtkowski},
title = {{Swept source OCT imaging of human anterior segment at 200 kHz}},
volume = {7163},
booktitle = {Ophthalmic Technologies XIX},
editor = {Fabrice Manns and Per G. S{\"o}derberg and Arthur Ho},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {716308},
abstract = {We present applicability of the high speed swept-source optical coherence tomography for in vivo imaging of the anterior segment of the human eye. Three dimensional imaging of the cornea with reduced motion artifacts is possible by using swept source with Fourier domain mode locking operating at 200kHz with 1300nm central wavelength. High imaging speeds allow for assessment of anterior and posterior corneal topography and generation of thickness and elevation maps.},
keywords = {Optical Coherence Tomography, Fourier domain detection methods, swept source OCT, anterior segment of the eye},
year = {2009},
doi = {10.1117/12.808555},
URL = {https://doi.org/10.1117/12.808555}
}
Robert Huber,
Fourier domain mode locking: new lasers for optical coherence tomography, 02 2009. Online: SPIE.
DOI:10.1117/2.1200901.1440
Bibtex: BibTeX
@Misc{HU_2009_Huber_b,
  Title                    = {{Fourier domain mode locking: new lasers for optical coherence tomography}},

  Author                   = {Huber, Robert},
  Year                     = {2009},

  Booktitle                = {SPIE Newsroom},
  Doi                      = {10.1117/2.1200901.1440},
  ISSN                     = {18182259},
keywords = {AG-Huber_FDML, AG-Huber_OCT},
  Url                      = {http://www.spie.org/x33321.xml}
}

2008

Thomas Klein, Wolfgang Wieser, Benjamin R. Biedermann, Christoph M. Eigenwillig, Gesa Palte, and Robert Huber,
Raman-pumped Fourier-domain mode-locked laser: analysis of operation and application for optical coherence tomography, Opt. Lett. , vol. 33, no. 23, pp. 2815-2817, Dec. 2008. Optica Publishing Group.
DOI:10.1364/OL.33.002815
Bibtex: BibTeX
@article{Klein:08,
author = {Thomas Klein and Wolfgang Wieser and Benjamin R. Biedermann and Christoph M. Eigenwillig and Gesa Palte and Robert Huber},
journal = {Opt. Lett.},
keywords = {Optical coherence tomography; Lasers, fiber; Lasers, Raman; Lasers, tunable; Optical coherence tomography; Laser operation; Mode locking; Optical coherence tomography; Optical components; Raman fiber lasers; Semiconductor lasers},
number = {23},
pages = {2815--2817},
publisher = {Optica Publishing Group},
title = {Raman-pumped Fourier-domain mode-locked laser: analysis of operation and application for optical coherence tomography},
volume = {33},
month = {Dec},
year = {2008},
url = {https://opg.optica.org/ol/abstract.cfm?URI=ol-33-23-2815},
doi = {10.1364/OL.33.002815},
abstract = {We demonstrate a Raman-pumped Fourier-domain mode-locked (FDML) fiber laser and optical coherence tomography imaging with this source. The wavelength sweep range of only 30 nm centered around 1550 nm results in limited axial resolution, hence a nonbiological sample is imaged. An output power of 1.9 mW was achieved at a sweep rate of 66 kHz and a maximum ranging depth of ~2.5 cm. Roll-off characteristics are found to be similar to FDML lasers with semiconductor optical amplifiers as gain media. The application of Raman gain also enables unperturbed cavity ring-down experiments in FDML lasers for the first time, providing direct access to the photon lifetime in the laser cavity. Good agreement with nonswept cw operation is proof of the stationary operation of FDML lasers.},
}
Vivek J. Srinivasan, Desmond C. Adler, Yueli Chen, Iwona Gorczynska, Robert Huber, Jay S. Duker, Joel S. Schuman, and James G. Fujimoto,
Ultrahigh-speed optical coherence tomography for three-dimensional and en face imaging of the retina and optic nerve head., Investigative Ophthalmology & Visual Science , vol. 49, no. 11, pp. 5103-5110, Nov. 2008.
DOI:10.1167/iovs.08-2127
Bibtex: BibTeX
@article{10.1167/iovs.08-2127,
    author = {Srinivasan, Vivek J. and Adler, Desmond C. and Chen, Yueli and Gorczynska, Iwona and Huber, Robert and Duker, Jay S. and Schuman, Joel S. and Fujimoto, James G.},
    title = "{Ultrahigh-Speed Optical Coherence Tomography for Three-Dimensional and En Face Imaging of the Retina and Optic Nerve Head}",
    journal = {Investigative Ophthalmology & Visual Science},
    volume = {49},
    number = {11},
    pages = {5103-5110},
    year = {2008},
    month = {11},
    abstract = "{  purpose. To demonstrate ultrahigh-speed optical coherence tomography (OCT) imaging of the retina and optic nerve head at 249,000 axial scans per second and a wavelength of 1060 nm. To investigate methods for visualization of the retina, choroid, and optic nerve using high-density sampling enabled by improved imaging speed.  methods. A swept-source OCT retinal imaging system operating at a speed of 249,000 axial scans per second was developed. Imaging of the retina, choroid, and optic nerve were performed. Display methods such as speckle reduction, slicing along arbitrary planes, en face visualization of reflectance from specific retinal layers, and image compounding were investigated.  results. High-definition and three-dimensional (3D) imaging of the normal retina and optic nerve head were performed. Increased light penetration at 1060 nm enabled improved visualization of the choroid, lamina cribrosa, and sclera. OCT fundus images and 3D visualizations were generated with higher pixel density and less motion artifacts than standard spectral/Fourier domain OCT. En face images enabled visualization of the porous structure of the lamina cribrosa, nerve fiber layer, choroid, photoreceptors, RPE, and capillaries of the inner retina.  conclusions. Ultrahigh-speed OCT imaging of the retina and optic nerve head at 249,000 axial scans per second is possible. The improvement of ∼5 to 10× in imaging speed over commercial spectral/Fourier domain OCT technology enables higher density raster scan protocols and improved performance of en face visualization methods. The combination of the longer wavelength and ultrahigh imaging speed enables excellent visualization of the choroid, sclera, and lamina cribrosa. }",
    issn = {1552-5783},
    doi = {10.1167/iovs.08-2127},
    url = {https://doi.org/10.1167/iovs.08-2127},
    eprint = {https://arvojournals.org/arvo/content\_public/journal/iovs/932946/z7g01108005103.pdf},
}
Benjamin R. Biedermann, Wolfgang Wieser, Christoph M. Eigenwillig, Gesa Palte, Desmond C. Adler, Vivek J. Srinivasan, James G. Fujimoto, and Robert Huber,
Real time en face Fourier-domain optical coherence tomography with direct hardware frequency demodulation, Opt. Lett. , vol. 33, no. 21, pp. 2556-2558, Oct. 2008. Optica Publishing Group.
DOI:10.1364/OL.33.002556
Bibtex: BibTeX
@article{Biedermann:08,
author = {Benjamin R. Biedermann and Wolfgang Wieser and Christoph M. Eigenwillig and Gesa Palte and Desmond C. Adler and Vivek J. Srinivasan and James G. Fujimoto and Robert Huber},
journal = {Opt. Lett.},
keywords = {Coherence imaging; Optical coherence tomography; Three-dimensional image acquisition; Lasers, tunable; Medical and biological imaging; Optical coherence tomography; Analog to digital converters; Interference; Laser sources; Medical imaging; Mode locking; Optical coherence tomography},
number = {21},
pages = {2556--2558},
publisher = {Optica Publishing Group},
title = {Real time en face Fourier-domain optical coherence tomography with direct hardware frequency demodulation},
volume = {33},
month = {Nov},
year = {2008},
url = {https://opg.optica.org/ol/abstract.cfm?URI=ol-33-21-2556},
doi = {10.1364/OL.33.002556},
abstract = {We demonstrate en face swept source optical coherence tomography (ss-OCT) without requiring a Fourier transformation step. The electronic optical coherence tomography (OCT) interference signal from a k-space linear Fourier domain mode-locked laser is mixed with an adjustable local oscillator, yielding the analytic reflectance signal from one image depth for each frequency sweep of the laser. Furthermore, a method for arbitrarily shaping the spectral intensity profile of the laser is presented, without requiring the step of numerical apodization. In combination, these two techniques enable sampling of the in-phase and quadrature signal with a slow analog-to-digital converter and allow for real-time display of en face projections even for highest axial scan rates. Image data generated with this technique is compared to en face images extracted from a three-dimensional OCT data set. This technique can allow for real-time visualization of arbitrarily oriented en face planes for the purpose of alignment, registration, or operator-guided survey scans while simultaneously maintaining the full capability of high-speed volumetric ss-OCT functionality.},
}
Christoph M. Eigenwillig, Benjamin R. Biedermann, Gesa Palte, and Robert Huber,
K-space linear Fourier domain mode locked laser and applications for optical coherence tomography, Opt. Express , vol. 16, no. 12, pp. 8916-8937, 06 2008. Optica Publishing Group.
DOI:10.1364/OE.16.008916
Bibtex: BibTeX
@article{Eigenwillig:08,
author = {Christoph M. Eigenwillig and Benjamin R. Biedermann and Gesa Palte and Robert Huber},
journal = {Opt. Express},
keywords = {Optical coherence tomography; Three-dimensional image acquisition; Interferometry; Lasers, tunable; Medical and biological imaging; Optical coherence tomography; Image quality; Laser modes; Laser sources; Medical imaging; Mode locking; Swept lasers},
number = {12},
pages = {8916--8937},
publisher = {Optica Publishing Group},
title = {K-space linear Fourier domain mode locked laser and applications for optical coherence tomography},
volume = {16},
month = {Jun},
year = {2008},
url = {https://opg.optica.org/oe/abstract.cfm?URI=oe-16-12-8916},
doi = {10.1364/OE.16.008916},
abstract = {We report on a Fourier Domain Mode Locked (FDML) wavelength swept laser source with a highly linear time-frequency sweep characteristic and demonstrate OCT imaging without k-space resampling prior to Fourier transformation. A detailed theoretical framework is provided and different strategies how to determine the optimum drive waveform of the piezo-electrically actuated optical bandpass-filter in the FDML laser are discussed. An FDML laser with a relative optical frequency deviation $\Delta$$\nu$/$\nu$ smaller than 8{\textperiodcentered}10-5 over a 100 nm spectral bandwidth at 1300 nm is presented, enabling high resolution OCT over long ranging depths. Without numerical time-to-frequency resampling and without spectral apodization a sensitivity roll off of 4 dB over 2 mm, 12.5 dB over 4 mm and 26.5 dB over 1 cm at 3.5 {\textmu}s sweep duration and 106.6 dB maximum sensitivity at 9.2 mW average power is achieved. The axial resolution in air degrades from 14 to 21 {\textmu}m over 4 mm imaging depth. The compensation of unbalanced dispersion in the OCT sample arm by an adapted tuning characteristic of the source is demonstrated. Good stability of the system without feedback-control loops is observed over hours.},
}
Christian Jirauschek, Christoph M. Eigenwillig, Benjamin R. Biedermann, and Robert Huber,
Fourier domain mode locking theory, in 2008 Conference on Lasers and Electro-Optics and 2008 Conference on Quantum Electronics and Laser Science , IEEE, 052008. pp. 1-2.
DOI:10.1109/CLEO.2008.4551638
Bibtex: BibTeX
@INPROCEEDINGS{4571888,
  author={Jirauschek, Christian and Eigenwillig, Christoph and Biedermann, Benjamin and Huber, Robert},
  booktitle={2008 Conference on Lasers and Electro-Optics and 2008 Conference on Quantum Electronics and Laser Science}, 
  title={Fourier domain mode locking theory}, 
  year={2008},
  volume={},
  number={},
  pages={1-2},
  abstract={We present a theoretical model for the recently developed Fourier domain mode locked (FDML) lasers. The good agreement with experiment provides valuable insights into the mechanism of FDML operation.},
  keywords={},
  doi={10.1109/CLEO.2008.4551638},
  ISSN={},
  month={May},}
Christoph M. Eigenwillig, Benjamin R. Biedermann, and Robert Huber,
Optical coherence tomography imaging with k-space linear Fourier Domain Mode Locked lasers, in 2008 Conference on Lasers and Electro-Optics and 2008 Conference on Quantum Electronics and Laser Science , IEEE, 052008. pp. 1-2.
DOI:10.1109/CLEO.2008.4551011
Bibtex: BibTeX
@INPROCEEDINGS{4571261,
  author={Eigenwillig, Christoph and Biedermann, Benjamin and Huber, Robert},
  booktitle={2008 Conference on Lasers and Electro-Optics and 2008 Conference on Quantum Electronics and Laser Science}, 
  title={Optical coherence tomography imaging with k-space linear fourier domain mode locked lasers}, 
  year={2008},
  volume={},
  number={},
  pages={1-2},
  abstract={We report on a Fourier Domain Mode Locked wavelength swept laser source with a highly linear time-frequency sweep characteristic and demonstrate OCT imaging without k-space resampling prior to Fourier transformation with this source.},
  keywords={},
  doi={10.1109/CLEO.2008.4551011},
  ISSN={},
  month={May},}
Peter M. Andrews, Yu Chen, Maristela L. Onozato, Shu-Wei Huang, Desmond C. Adler, Robert Huber, James Jiang, Scott E Barry, Alex E. Cable, and James G. Fujimoto,
High-resolution optical coherence tomography imaging of the living kidney, Laboratory Investigation , vol. 88, no. 4, pp. 441-449, 04 2008.
DOI:10.1038/labinvest.2008.4
Bibtex: BibTeX
@article{ANDREWS2008441,
title = {High-resolution optical coherence tomography imaging of the living kidney},
journal = {Laboratory Investigation},
volume = {88},
number = {4},
pages = {441-449},
year = {2008},
issn = {0023-6837},
doi = {https://doi.org/10.1038/labinvest.2008.4},
url = {https://www.sciencedirect.com/science/article/pii/S0023683722019158},
author = {Peter M Andrews and Yu Chen and Maristela L Onozato and Shu-Wei Huang and Desmond C Adler and Robert A Huber and James Jiang and Scott E Barry and Alex E Cable and James G Fujimoto},
keywords = {ischemia, kidney, optical coherence tomography (OCT), renal pathology, three-dimensional imaging, renal transplantation},
abstract = {Optical coherence tomography (OCT) is a rapidly emerging imaging modality that can provide non-invasive, cross-sectional, high-resolution images of tissue morphology in situ and in real-time. In the present series of studies, we used a high-speed OCT imaging system equipped with a frequency-swept laser light source (1.3 μm wavelength) to study living kidneys in situ. Adult, male Munich–Wistar rats were anesthetized, a laparotomy was performed and the living kidneys were exposed for in situ observation. We observed the kidneys prior to, during and following exposure to renal ischemia induced by clamping the renal artery. The effects of intravenous mannitol infusion (1.0 ml of 25%) prior to and during renal ischemia were also studied. Finally, living kidneys were flushed with a renal preservation solution, excised and observed while being stored at 0–4°C. Three-dimensional OCT data sets enabled visualization of the morphology of the uriniferous tubules and the renal corpuscles. When renal ischemia was induced, OCT revealed dramatic shrinkage of tubular lumens due to swelling of the lining epithelium. Three-dimensional visualization and volumetric rendering software provided an accurate evaluation of volumetric changes in tubular lumens in response to renal ischemia. Observations of kidneys flushed with a renal preservation solution and stored at 0–4°C also revealed progressive and significant loss of tubular integrity over time. Intravenous infusion of mannitol solution resulted in thinning of the tubular walls and an increase in the tubular lumen diameters. Mannitol infusion also prevented the cell swelling that otherwise resulted in shrinkage of proximal tubule lumens during ischemia. We conclude that OCT represents an exciting new approach to visualize, in real-time, pathological changes in the living kidney in a non-invasive fashion. Possible clinical applications are discussed.}
}
Desmond C. Adler, Yu Chen, Robert Huber, Joseph M. Schmitt, James Connolly, and James G. Fujimoto,
In vivo endomicroscopy using three-dimensional optical coherence tomography and Fourier domain mode locked lasers, in Coherence Domain Optical Methods and Optical Coherence Tomography in Biomedicine XII , Joseph A. Izatt and James G. Fujimoto and Valery V. Tuchin, Eds. SPIE, 032008. pp. 684708.
DOI:10.1117/12.761850
Bibtex: BibTeX
@inproceedings{10.1117/12.761850,
author = {Desmond C. Adler and Yu Chen and Robert Huber and Joseph Schmitt and James Connolly and James G. Fujimoto},
title = {{In vivo endomicroscopy using three-dimensional optical coherence tomography and Fourier domain mode locked lasers}},
volume = {6847},
booktitle = {Coherence Domain Optical Methods and Optical Coherence Tomography in Biomedicine XII},
editor = {Joseph A. Izatt and James G. Fujimoto and Valery V. Tuchin},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {684708},
abstract = {We report an endoscopic optical coherence tomography (OCT) system based on a Fourier Domain Mode Locked
(FDML) laser, a novel data acquisition (DAQ) system with optical frequency clocking, and a high-speed spiralscanning
fiber probe. The system is capable of acquiring three-dimensional (3D) in vivo datasets at 100,000 axial
lines/s and 50 frames/s, enabled by the high sweep rates of the FDML laser and the efficient data processing of
the DAQ system. This high imaging rate allows densely-sampled 3D datasets to be acquired, giving a resolvable
feature size of 9 &mgr;m x 20 &mgr;m x 7 &mgr;m (transverse x longitudinal x axial, XYZ). In vivo 3D endomicroscopy is
demonstrated in the rabbit colon, where individual colonic crypts are clearly visualized and measured. With
further improvements in DAQ technology, the imaging speed will be scalable to the hundreds of thousands of
axial lines/s supported by FDML lasers.},
keywords = {Optical coherence tomography, Endoscopic microscopy, Fourier Domain Mode Locked lasers, FDML, Three dimensional microscopy, In vivo microscopy, Biomedical optics, Swept source optical coherence tomography},
year = {2008},
doi = {10.1117/12.761850},
URL = {https://doi.org/10.1117/12.761850}
}
Tomasz Bajraszewski, Maciej Wojtkowski, Maciej Szkulmowski, Anna Szkulmowska, Robert Huber, and Andrzej M. Kowalczyk,
Improved spectral optical coherence tomography using optical frequency comb, Opt. Express , vol. 16, no. 6, pp. 4163-4176, 03 2008. Optica Publishing Group.
DOI:10.1364/OE.16.004163
Bibtex: BibTeX
@article{Bajraszewski:08,
author = {Tomasz Bajraszewski and Maciej Wojtkowski and Maciej Szkulmowski and Anna Szkulmowska and Robert Huber and Andrzej Kowalczyk},
journal = {Opt. Express},
keywords = {Optical coherence tomography; Fabry-Perot; Image reconstruction techniques; Multiframe image processing ; Frequency combs; Medical imaging; Ophthalmic imaging; Optical coherence tomography; Swept sources; Three dimensional imaging},
number = {6},
pages = {4163--4176},
publisher = {Optica Publishing Group},
title = {Improved spectral optical coherence tomography using optical frequency comb},
volume = {16},
month = {Mar},
year = {2008},
url = {https://opg.optica.org/oe/abstract.cfm?URI=oe-16-6-4163},
doi = {10.1364/OE.16.004163},
abstract = {We identify and analyze factors influencing sensitivity drop-off in Spectral OCT and propose a system employing an Optical Frequency Comb (OFC) to verify this analysis. Spectral Optical Coherence Tomography using a method based on an optical frequency comb is demonstrated. Since the spectrum sampling function is determined by the comb rather than detector pixel distribution, this method allows to overcome limitations of high resolution Fourier-domain OCT techniques. Additionally, the presented technique also enables increased imaging range while preserving high axial resolution. High resolution cross-sectional images of biological samples obtained with the proposed technique are presented.},
}
Desmond C. Adler, Shu-Wei Huang, Robert Huber, and James G. Fujimoto,
Photothermal detection of gold nanoparticles using phase-sensitive optical coherence tomography, Opt. Express , vol. 16, no. 7, pp. 4376-4393, 03 2008. Optica Publishing Group.
DOI:10.1364/OE.16.004376
Bibtex: BibTeX
@article{Adler:08,
author = {Desmond C. Adler and Shu-Wei Huang and Robert Huber and James G. Fujimoto},
journal = {Opt. Express},
keywords = {Optical coherence tomography; Phase measurement; Lasers, tunable; Nanomaterials; Laser beams; Medical imaging; Multimode lasers; Optical Doppler tomography; Phase modulation; Single mode lasers},
number = {7},
pages = {4376--4393},
publisher = {Optica Publishing Group},
title = {Photothermal detection of gold nanoparticles using phase-sensitive optical coherence tomography},
volume = {16},
month = {Mar},
year = {2008},
url = {https://opg.optica.org/oe/abstract.cfm?URI=oe-16-7-4376},
doi = {10.1364/OE.16.004376},
abstract = {The detection of a gold nanoparticle contrast agent is demonstrated using a photothermal modulation technique and phase sensitive optical coherence tomography (OCT). A focused beam from a laser diode at 808 nm is modulated at frequencies of 500 Hz--60 kHz while irradiating a solution containing nanoshells. Because the nanoshells are designed to have a high absorption coefficient at 808 nm, the laser beam induces small-scale localized temperature oscillations at the modulation frequency. These temperature oscillations result in optical path length changes that are detected by a phase-sensitive, swept source OCT system. The OCT system uses a double-buffered Fourier domain mode locked (FDML) laser operating at a center wavelength of 1315 nm and a sweep rate of 240 kHz. High contrast is observed between phantoms containing nanoshells and phantoms without nanoshells. This technique represents a new method for detecting gold nanoparticle contrast agents with excellent signal-to-noise performance at high speeds using OCT.},
}

2007

Desmond C. Adler, Yu Chen, Robert Huber, Joseph M. Schmitt, James Connolly, and James G. Fujimoto,
Three-dimensional endomicroscopy using optical coherence tomography, Nature Photonics , vol. 1, no. 12, pp. 709-716, Nov. 2007.
DOI:10.1038/nphoton.2007.228
Bibtex: BibTeX
@article{HU_2007_Adlera,
  Title                    = {Three-dimensional endomicroscopy using optical coherence tomography},
  Author                   = {Adler, Desmond C. and Chen, Yu and Huber, Robert and Schmitt, Joseph and Connolly, James and Fujimoto, James G.},
  Journal                  = {Nature Photonics},
  Year                     = {2007},
  Month                    = nov,
  Number                   = {12},
  Pages                    = {709--716},
  Volume                   = {1},
  Doi                      = {10.1038/nphoton.2007.228},
Timestamp                = {2014.11.20},
  ISSN                     = {1749-4885}
}
Laura A. Kranendonk, Xinliang An, Andrew W. Caswell, Randy E. Herold, Scott T. Sanders, Robert Huber, James G. Fujimoto, Yasuhiro Okura, and Yasuhiro Urata,
High speed engine gas thermometry by Fourier-domain mode-locked laser absorption spectroscopy, Opt. Express , vol. 15, no. 23, pp. 15115-15128, Nov. 2007. Optica Publishing Group.
DOI:10.1364/OE.15.015115
Bibtex: BibTeX
@article{Kranendonk:07,
author = {Laura A. Kranendonk and Xinliang An and Andrew W. Caswell and Randy E. Herold and Scott T. Sanders and Robert Huber and James G. Fujimoto and Yasuhiro Okura and Yasuhiro Urata},
journal = {Opt. Express},
keywords = {Spectrometers and spectroscopic instrumentation; Lasers, tunable; Spectroscopy, fluorescence and luminescence; Absorption; Spectroscopy, diode lasers; Spectroscopy, infrared; Fourier transform spectroscopy; Laser modes; Laser sources; Laser spectroscopy; Molecular spectra; Optical coherence tomography},
number = {23},
pages = {15115--15128},
publisher = {Optica Publishing Group},
title = {High speed engine gas thermometry by Fourier-domain mode-locked laser absorption spectroscopy},
volume = {15},
month = {Nov},
year = {2007},
url = {https://opg.optica.org/oe/abstract.cfm?URI=oe-15-23-15115},
doi = {10.1364/OE.15.015115},
abstract = {We present a novel method for low noise, high-speed, real-time spectroscopy to monitor molecular absorption spectra. The system is based on a rapidly swept, narrowband CW Fourier-domain mode-locked (FDML) laser source for spectral encoding in time and an optically time-multiplexed split-pulse data acquisition system for improved noise performance and sensitivity. An acquisition speed of $\sim$100 kHz, a spectral resolution better than 0.1 nm over a wavelength range of $\sim$1335--1373 nm and a relative noise level of $\sim$5 mOD ($\sim$1\% minimum detectable base-e absorbance) are achieved. The system is applied for crank-angle-resolved gas thermometry by H2O absorption spectroscopy in an engine motoring at 600 and 900 rpm with a precision of $\sim$1\%. Influences of various noise sources such as laser phase and intensity noise, trigger and synchronization jitter in the electronic detection system, and the accuracy of available H2O absorption databases are discussed.},
}

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