@inproceedings{10.1117/12.704084,
author = {Robert A. Huber and Desmond C. Adler and Vivek J. Srinivasan and Iwona M Gorczynska and James G. Fujimoto},
title = {{Fourier domain mode-locked (FDML) lasers at 1050 nm and 202,000 sweeps per second for OCT retinal imaging}},
volume = {6429},
booktitle = {Coherence Domain Optical Methods and Optical Coherence Tomography in Biomedicine XI},
editor = {James G. Fujimoto and Joseph A. Izatt and Valery V. Tuchin},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {642907},
abstract = {Retinal imaging ranks amongst the most important clinical applications for optical coherence
tomography (OCT) [1, 2]. The recent demonstration of increased sensitivity [3-6] in Fourier
Domain detection [7, 8] has opened the way for dramatically higher imaging speeds, up to axial
scan rates of several tens of kilohertz. However, these imaging speeds are still not sufficient for
high density 3D datasets and a further increase to several hundreds of kilohertz is necessary. In
this paper we demonstrate a swept laser source at 1050 nm with a sweep rate of 202 kHz. The
laser source provides ~10 mW average output power, up to 60 nm total sweep range and a
sensitivity roll off of less than 10 dB over 4 mm. In vivo 2D and 3D imaging of the human retina
at a record axial scan rate of 101 kHz is demonstrated. These results suggest that swept source
OCT has the potential to significantly outperform spectral/Fourier domain OCT for ophthalmic
imaging applications in the future.},
keywords = {tunable laser, optical coherence tomography, Fourier domain mode locking, swept source, OCT, FDML, retinal imaging, ophthalmic imaging},
year = {2007},
doi = {10.1117/12.704084},
URL = {https://doi.org/10.1117/12.704084}
}

@inproceedings{10.1117/12.704128,
author = {Desmond C. Adler and Robert Huber and James G. Fujimoto},
title = {{Phase-sensitive optical coherence tomography using buffered Fourier domain mode-locked lasers at up to 370,000 scans per second}},
volume = {6429},
booktitle = {Coherence Domain Optical Methods and Optical Coherence Tomography in Biomedicine XI},
editor = {James G. Fujimoto and Joseph A. Izatt and Valery V. Tuchin},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {64291L},
abstract = {Phase sensitive optical coherence tomography (OCT) can be used to obtain sub-nanometer
displacement measurements of biological and non-biological samples. This technique has many
applications, including detection of small amplitude surface motion, and high axial resolution OCT
phase microscopy. Doppler OCT is another type of phase sensitive imaging, where differential
phase measurements are used to detect fluid flow in biological specimens. For all types of phase
sensitive OCT, a light source with low phase noise is required in order to provide good
displacement sensitivity. High speed imaging is also necessary in order to minimize motion artifacts
and enable the detection of fast transient events. In this manuscript, buffered Fourier Domain Mode
Locked (FDML) lasers are demonstrated for ultrahigh-speed phase sensitive OCT detection. The
lasers are operated at sweep speeds of 42, 117, and 370 kHz, and displacement sensitivities of 39,
52, and 102 pm are achieved, respectively. These displacement sensitivities are comparable to
spectrometer-based phase sensitive OCT systems, but acquisition speeds 1.4 - 13x faster are
possible using buffered FDML lasers. An additional factor of √2 improvement in noise performance
is observed for differential phase measurements, which has important implications for Doppler
OCT. Dynamic measurements of rapid, small-amplitude piezoelectric transducer motion are
demonstrated. In general, buffered FDML lasers provide excellent displacement sensitivities at
extremely high sweep speeds for phase sensitive OCT measurements.},
keywords = {optical coherence tomography, OCT, optical coherence phase microscopy, swept source phase microscopy, doppler optical coherence tomography, frequency swept lasers, Fourier Domain Mode Locked lasers, FDML},
year = {2007},
doi = {10.1117/12.704128},
URL = {https://doi.org/10.1117/12.704128}
}

@article{Srinivasan:07,
author = {V. J. Srinivasan and R. Huber and I. Gorczynska and J. G. Fujimoto and J. Y. Jiang and P. Reisen and A. E. Cable},
journal = {Opt. Lett.},
keywords = {Optical coherence tomography; Lasers, tunable; Medical and biological imaging; Optical coherence tomography; Retina scanning; Semiconductor lasers; Semiconductor optical amplifiers; Spontaneous emission; Tunable lasers},
number = {4},
pages = {361--363},
publisher = {Optica Publishing Group},
title = {High-speed, high-resolution optical coherence tomography retinal imaging with a frequency-swept laser at 850 nm},
volume = {32},
month = {Feb},
year = {2007},
url = {https://opg.optica.org/ol/abstract.cfm?URI=ol-32-4-361},
doi = {10.1364/OL.32.000361},
abstract = {High-speed, high-resolution optical coherence tomography (OCT) imaging of the human retina is demonstrated using a frequency-swept laser at 850 nm. A compact external cavity semiconductor laser design, optimized for swept-source ophthalmic OCT, is described. The laser enables an effective 16 kHz sweep rate with \>10 mm coherence length and a tuning range of $\sim$35 nm full width at half-maximum, yielding an axial resolution of \<7 $\mu$m in tissue.},
}

@article{KRANENDONK2007783,
title = {Wavelength-agile H2O absorption spectrometer for thermometry of general combustion gases},
journal = {Proceedings of the Combustion Institute},
volume = {31},
number = {1},
pages = {783-790},
year = {2007},
issn = {1540-7489},
doi = {https://doi.org/10.1016/j.proci.2006.08.003},
url = {https://www.sciencedirect.com/science/article/pii/S1540748906002665},
author = {Laura A. Kranendonk and Robert Huber and James G. Fujimoto and Scott T. Sanders},
keywords = {Thermometry, Wavelength-agile, Absorption spectroscopy},
abstract = {Using a novel Fourier-domain mode-locking (FDML) laser scanning 1330–1380nm, we have developed a gas thermometer based on absorption spectroscopy that is appropriate for combustion gases at essentially arbitrary conditions. The path-integrated measurements are particularly useful in homogeneous environments, and here we present measurements in a controlled piston engine and a shock tube. Engine measurements demonstrate a RMS temperature precision of ±3% at 1500K and 200kHz bandwidth; the precision is improved dramatically by averaging. Initial shock tube measurements place the absolute accuracy of the thermometer within ∼2% to 1000K. The sensor performs best when significant H2O vapor is present, but requires only XH2OL>0.07cm at 300K, XH2OL>0.25cm at 1000K, or XH2OL>1.25cm at 3000K for 2% accurate thermometry, assuming a 4kHz measurement bandwidth (200kHz scans with 50 averages). The sensor also provides H2O mole fraction and shows potential for monitoring gas pressure based on the broadening of spectral features. To aid in designing other sensors based on high-temperature, high-pressure H2O absorption spectroscopy, a database of measured spectra is included.}
}

@article{Huber:06,
author = {Robert Huber and Desmond C. Adler and James G. Fujimoto},
journal = {Opt. Lett.},
keywords = {Optical coherence tomography; Lasers, tunable; Amplified spontaneous emission; Fourier domain mode locking; Image quality; Laser sources; Optical coherence tomography; Swept sources},
number = {20},
pages = {2975--2977},
publisher = {Optica Publishing Group},
title = {Buffered Fourier domain mode locking: unidirectional swept laser sources for optical coherence tomography imaging at 370,000 lines/s},
volume = {31},
month = {Oct},
year = {2006},
url = {https://opg.optica.org/ol/abstract.cfm?URI=ol-31-20-2975},
doi = {10.1364/OL.31.002975},
abstract = {We describe buffered Fourier domain mode locking (FDML), a technique for tailoring the output and multiplying the sweep rate of FDML lasers. Buffered FDML can be used to create unidirectional wavelength sweeps from the normal bidirectional sweeps in an FDML laser without sacrificing sweep rate. We also investigate the role of the laser source in dynamic range versus sensitivity performance in optical coherence tomography (OCT) imaging. Unidirectional sweep rates of 370 kHz over a 100 nm range at a center wavelength of 1300 nm are achieved. High-speed, swept-source OCT is demonstrated at record speeds of up to 370,000 axial scans per second.},
}

@article{LENZ2006255,
title = {First Steps of Retinal Photoisomerization in Proteorhodopsin},
journal = {Biophysical Journal},
volume = {91},
number = {1},
pages = {255-262},
year = {2006},
issn = {0006-3495},
doi = {https://doi.org/10.1529/biophysj.105.074690},
url = {https://www.sciencedirect.com/science/article/pii/S0006349506717258},
author = {Martin O. Lenz and Robert Huber and Bernhard Schmidt and Peter Gilch and Rolf Kalmbach and Martin Engelhard and Josef Wachtveitl},
abstract = {The early steps (<1ns) in the photocycle of the detergent solubilized proton pump proteorhodopsin are analyzed by ultrafast spectroscopic techniques. A comparison to the first primary events in reconstituted proteorhodopsin as well as to the well known archaeal proton pump bacteriorhodopsin is given. A dynamic Stokes shift observed in fs-time-resolved fluorescence experiments allows a direct observation of early motions on the excited state potential energy surface. The initial dynamics is dominated by sequentially emerging stretching (<150fs) and torsional (∼300fs) modes of the retinal. The different protonation states of the primary proton acceptor Asp-97 drastically affect the reaction rate and the overall quantum efficiencies of the isomerization reactions, mainly evidenced for time scales above 1ps. However, no major influence on the fast time scales (∼150fs) could be seen, indicating that the movement out of the Franck-Condon region is fairly robust to electrostatic changes in the retinal binding pocket. Based on fs-time-resolved absorption and fluorescence spectra, ground and exited state contributions can be disentangled and allow to construct a reaction model that consistently explains pH-dependent effects in solubilized and reconstituted proteorhodopsin.}
}

@INPROCEEDINGS{4627914,
  author={Huber, R. and Wojtkowski, M. and Fujimoto, J. G.},
  booktitle={2006 Conference on Lasers and Electro-Optics and 2006 Quantum Electronics and Laser Science Conference}, 
  title={Fourier Domain Mode Locking (FDML): Three-dimensional OCT imaging at 906 frames per second}, 
  year={2006},
  volume={},
  number={},
  pages={1-2},
  abstract={Fourier domain mode locking is a new operation regime of lasers. Highly chirped frequency swept waveforms rather than short pulses are generated. The mechanism and its application for ultrahigh-speed biomedical OCT imaging are discussed.},
  keywords={},
  doi={10.1109/CLEO.2006.4627914},
  ISSN={2160-9004},
  month={May},}

@article{Huber:06,
author = {R. Huber and M. Wojtkowski and J. G. Fujimoto},
journal = {Opt. Express},
keywords = {Optical coherence tomography; Lasers, tunable; Frequency modulated lasers; Full field optical coherence tomography; Laser operation; Light fields; Medical imaging; Mode locking},
number = {8},
pages = {3225--3237},
publisher = {Optica Publishing Group},
title = {Fourier Domain Mode Locking (FDML): A new laser operating regime and applications for optical coherence tomography},
volume = {14},
month = {Apr},
year = {2006},
url = {https://opg.optica.org/oe/abstract.cfm?URI=oe-14-8-3225},
doi = {10.1364/OE.14.003225},
abstract = {We demonstrate a new technique for frequency-swept laser operation--Fourier domain mode locking (FDML)--and its application for swept-source optical coherence tomography (OCT) imaging. FDML is analogous to active laser mode locking for short pulse generation, except that the spectrum rather than the amplitude of the light field is modulated. High-speed, narrowband optical frequency sweeps are generated with a repetition period equal to the fundamental or a harmonic of cavity round-trip time. An FDML laser is constructed using a long fiber ring cavity, a semiconductor optical amplifier, and a tunable fiber Fabry-Perot filter. Effective sweep rates of up to 290 kHz are demonstrated with a 105 nm tuning range at 1300 nm center wavelength. The average output power is 3 mW directly from the laser and 20 mW after post-amplification. Using the FDML laser for swept-source OCT, sensitivities of 108 dB are achieved and dynamic linewidths are narrow enough to enable imaging over a 7 mm depth with only a 7.5 dB decrease in sensitivity. We demonstrate swept-source OCT imaging with acquisition rates of up to 232,000 axial scans per second. This corresponds to 906 frames/second with 256 transverse pixel images, and 3.5 volumes/second with a 256{\texttimes}128{\texttimes}256 voxel element 3-D OCT data set. The FDML laser is ideal for swept-source OCT imaging, thus enabling high imaging speeds and large imaging depths.},
}

@TechReport{HU_2006_Kranendonk_a,
  Title                    = {{Measurements of Gas Temperature in a HCCI Engine Using a Fourier Domain Mode Locking Laser}},
  Author                   = {Kranendonk, Laura A and Walewski, Joachim W and Sanders, Scott T and Huber, Robert and Fujimoto, James G},
  Year                     = {2006},
  Month                    = apr,
  pages  = {1366 1--5},
  Doi                      = {10.4271/2006-01-1366},
keywords = {AG-Huber_FDML, AG-Huber_OCT},
  Url                      = {http://www.sae.org/technical/papers/2006-01-1366}
}

@inproceedings{10.1117/12.648880,
author = {R. Huber and K. Taira and M. Wojtkowski and J. G. Fujimoto},
title = {{Fourier domain mode-locked lasers for swept source OCT imaging at up to 290 kHz scan rates}},
volume = {6079},
booktitle = {Coherence Domain Optical Methods and Optical Coherence Tomography in Biomedicine X},
editor = {Valery V. Tuchin and Joseph A. Izatt and James G. Fujimoto},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {60790U},
abstract = {A new type of laser operation, Fourier Domain Mode Locking (FDML), is demonstrated for high performance, frequency swept light sources.  FDML achieves superior sweep speeds, coherence lengths and bandwidths compared to standard bulk or fiber lasers.  At 1300 nm a sweep range up to 145 nm, up to 4 cm delay length, and sweep rates up to 290 kHz were achieved.  This light source is demonstrated for swept source OCT imaging.},
keywords = {Fourier Domain Mode Locking, swept laser, tunable laser, wavelength agile, optical coherence tomography, spectral domain, Fourier domain, fiber laser},
year = {2006},
doi = {10.1117/12.648880},
URL = {https://doi.org/10.1117/12.648880}
}

@inproceedings{Kranendonk:06,
author = {Laura A. Kranendonk and Joachim W. Walewski and Scott T. Sanders and Robert Huber and James G. Fujimoto},
booktitle = {Laser Applilcations to Chemical, Security and Environmental Analysis},
journal = {Laser Applilcations to Chemical, Security and Environmental Analysis},
keywords = {Lasers and laser optics; Diode lasers; Lasers, tunable; Laser operation; Laser sensors; Lasers; Mode locking; Spontaneous emission; Tunable diode lasers},
pages = {TuB2},
publisher = {Optica Publishing Group},
title = {Measurements of gas temperature in an HCCI engine by use of a Fourier-domain mode-locking laser},
year = {2006},
url = {https://opg.optica.org/abstract.cfm?URI=LACSEA-2006-TuB2},
doi = {10.1364/LACSEA.2006.TuB2},
abstract = {Initial measurements of water vapor temperature by use of a Fourier-domain mode-locking laser were performed in a homogenous charge compression ignition engine. We assessed the potential of this FDML laser in combustion applications.},
}

@article{Huber:05,
author = {R. Huber and M. Wojtkowski and J. G. Fujimoto and J. Y. Jiang and A. E. Cable},
journal = {Opt. Express},
keywords = {Optical coherence tomography; Lasers, tunable; High speed imaging; Image fusion; Laser sources; Semiconductor lasers; Swept lasers; Three dimensional imaging},
number = {26},
pages = {10523--10538},
publisher = {Optica Publishing Group},
title = {Three-dimensional and C-mode OCT imaging with a compact, frequency swept laser source at 1300 nm},
volume = {13},
month = {Dec},
year = {2005},
url = {https://opg.optica.org/oe/abstract.cfm?URI=oe-13-26-10523},
doi = {10.1364/OPEX.13.010523},
abstract = {We demonstrate high resolution, three-dimensional OCT imaging with a high speed, frequency swept 1300 nm laser source. A new external cavity semiconductor laser design, optimized for application to swept source OCT, is discussed. The design of the laser enables adjustment of an internal spectral filter to change the filter bandwidth and provides a robust bulk optics design. The laser generates ~30 mW instantaneous peak power at an effective 16 kHz sweep rate with a tuning range of ~133 nm full width. In frequency domain reflectometry and OCT applications, 109 dB sensitivity and ~10 $\mu$m axial resolution in tissue can be achieved with the swept laser. The high imaging speeds enable three-dimensional OCT imaging, including zone focusing or C-mode imaging and image fusion to acquire large depth of field data sets with high resolution. In addition, three-dimensional OCT data provides coherence gated en face images similar to optical coherence microscopy (OCM) and also enables the generation of images similar to confocal microscopy by summing signals in the axial direction. High speed, three-dimensional OCT imaging can provide comprehensive data which combines the advantages of optical coherence tomography and microscopy in a single system.},
}

@inproceedings{10.1117/12.641732,
author = {R. Huber and K. Taira and M. Wojtkowski and J. G. Fujimoto},
title = {{Fourier domain mode locked lasers for OCT imaging at up to 290 kHz sweep rates}},
volume = {5861},
booktitle = {Optical Coherence Tomography and Coherence Techniques II},
editor = {Wolfgang Drexler},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {58611B},
abstract = {A high speed, tunable laser using Fourier Domain Mode Locking is demonstrated for OCT imaging.  Record sweep speeds up to 290 kHz, 3 cm coherence length and 145 nm range at 1300 nm are achieved.},
keywords = {Fourier domain mode locking, swept source, swept laser, tunable laser, wavelength agile laser, optical coherence tomography, spectral OCT, Fourier domain},
year = {2005},
doi = {10.1117/12.641732},
URL = {https://doi.org/10.1117/12.641732}
}

@InProceedings{HU_2005_Huber_a,
  Title                    = {{Fourier Domain Mode Locking: Overcoming limitations of frequency swept light sources and pulsed lasers}},
  Author                   = {Huber, Robert A and Taira, Kenji and Fujimoto, James G},
  Booktitle                = {Conference on Lasers and Electro-Optics Europe/ European Quantum Electronics Conference (CLEO/Europe - EQEC 2005)},
keywords = {AG-Huber_FDML, AG-Huber_OCT},
  Year                     = { 2005}
}

@inproceedings{Sharma:05,
author = {V. Sharma and A. M. Kowalevicz and R. Huber and J. G. Fujimoto and K. Minoshima},
booktitle = {Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science and Photonic Applications Systems Technologies},
journal = {Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science and Photonic Applications Systems Technologies},
keywords = {Optical design and fabrication; Microstructure fabrication; Ultrafast optics; Ultrafast processes in condensed matter, including semiconductors; Femtosecond lasers; Femtosecond pulses; Free electron lasers; High numerical aperture optics; Three dimensional fabrication; Ti:sapphire lasers},
pages = {CThCC4},
publisher = {Optica Publishing Group},
title = {Three dimensional waveguide splitters fabricated in glass using a femtosecond laser oscillator},
year = {2005},
url = {https://opg.optica.org/abstract.cfm?URI=CLEO-2005-CThCC4},
abstract = {Three-dimensional optical waveguide devices are fabricated in glass using femtosecond pulses from an extended cavity Ti:sapphire laser oscillator. We demonstrate increased device densities by fabricating highly symmetric 1:N waveguide splitters in three dimensions.},
}

@inproceedings{Huber:05,
author = {R. Huber and K. Taira and T. H. Ko and M. Wojtkowski and V. Srinivasan and J. G. Fujimoto and K. Hsu},
booktitle = {Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science and Photonic Applications Systems Technologies},
journal = {Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science and Photonic Applications Systems Technologies},
keywords = {Imaging systems; Optical coherence tomography; Lasers and laser optics; Lasers, tunable; Laser amplifiers; Laser sources; Light sources; Optical coherence tomography; Point spread function; Ring lasers},
pages = {JThE33},
publisher = {Optica Publishing Group},
title = {High-speed, amplified, frequency swept laser at 20 kHz sweep rates for OCT imaging},
year = {2005},
url = {https://opg.optica.org/abstract.cfm?URI=QELS-2005-JThE33},
abstract = {We demonstrate a high-speed, frequency swept, 1300 nm laser for Fourier domain OCT. The laser generates ~45 mW instantaneous power with 20 kHz sweep rates and achieves 108 dB sensitivity and 12.7 um resolution.},
}

@article{Huber:05,
author = {R. Huber and M. Wojtkowski and K. Taira and J. G. Fujimoto and K. Hsu},
journal = {Opt. Express},
keywords = {Optical coherence tomography; Lasers, tunable; Fiber lasers; Fiber optic amplifiers; Fiber optic components; Laser sources; Light sources; Tunable diode lasers},
number = {9},
pages = {3513--3528},
publisher = {Optica Publishing Group},
title = {Amplified, frequency swept lasers for frequency domain reflectometry and OCT imaging: design and scaling principles},
volume = {13},
month = {May},
year = {2005},
url = {https://opg.optica.org/oe/abstract.cfm?URI=oe-13-9-3513},
doi = {10.1364/OPEX.13.003513},
abstract = {We demonstrate a high-speed, frequency swept, 1300 nm laser source for frequency domain reflectometry and OCT with Fourier domain/swept-source detection. The laser uses a fiber coupled, semiconductor amplifier and a tunable fiber Fabry-Perot filter. We present scaling principles which predict the maximum frequency sweep speed and trade offs in output power, noise and instantaneous linewidth performance. The use of an amplification stage for increasing output power and for spectral shaping is discussed in detail. The laser generates ~45 mW instantaneous peak power at 20 kHz sweep rates with a tuning range of ~120 nm full width. In frequency domain reflectometry and OCT applications the frequency swept laser achieves 108 dB sensitivity and ~10 {\textmu}m axial resolution in tissue. We also present a fast algorithm for real time calibration of the fringe signal to equally spaced sampling in frequency for high speed OCT image preview.},
}

@inproceedings{10.1117/12.592552,
author = {Robert Huber and Kenji Taira and Maciej Wojtkowski and Tony Hong-Tyng Ko and James G. Fujimoto and Kevin Hsu},
title = {{High-speed-frequency swept light source for Fourier domain OCT at 20-kHz A-scan rate}},
volume = {5690},
booktitle = {Coherence Domain Optical Methods and Optical Coherence Tomography in Biomedicine IX},
editor = {Valery V. Tuchin and Joseph A. Izatt and James G. Fujimoto},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {96 -- 100},
abstract = {We demonstrate a high-speed tunable, continuous wave laser source for Fourier domain OCT.  The laser source is based on a fiber coupled, semiconductor optical amplifier and a tunable ultrahigh finesse, fiber Fabry Perot filter for frequency tuning.  The light source provides frequency scan rates of up to 20,000 sweeps per second over a wavelength range of >70 nm FWHM at 1330 nm, yielding an axial resolution of ~14 μm in air.  The linewidth is narrow and corresponds to a coherence length of several mm, enabling OCT imaging over a large axial range.},
keywords = {swept source, Fourier Domain, OCT, tunable laser, Spectral Domain, frequency domain imaging, OFDI, sweep},
year = {2005},
doi = {10.1117/12.592552},
URL = {https://doi.org/10.1117/12.592552}
}

@article{doi:10.1021/bi048318h,
author = {Huber, Robert and Köhler, Thomas and Lenz, Martin O. and Bamberg, Ernst and Kalmbach, Rolf and Engelhard, Martin and Wachtveitl, Josef},
title = {pH-Dependent Photoisomerization of Retinal in Proteorhodopsin},
journal = {Biochemistry},
volume = {44},
number = {6},
pages = {1800-1806},
year = {2005},
doi = {10.1021/bi048318h},
note ={PMID: 15697205},
URL = {https://doi.org/10.1021/bi048318h},
eprint = {https://doi.org/10.1021/bi048318h},
abstract = {The early steps in the photocycle of the bacterial proton pump proteorhodopsin (PR) were analyzed by ultrafast pump/probe spectroscopy to compare the rate of retinal isomerization at alkaline and acidic pH values. At pH 9, the functionally important primary proton acceptor (Asp97, pKa = 7.7) is negatively charged; consequently, a reaction cycle analogous to the archaeal bacteriorhodopsin (BR) is observed. The excited electronic state of PR displays a pronounced biphasic decay with time constants of 400 fs and 8 ps. At pH 6 where Asp97 is protonated a similar biphasic decay is observed, although it is significantly slower (700 fs and 15 ps). The results indicate, in agreement to similar findings in other retinal proteins, that also in PR the charge distribution within the chromophore binding pocket is a major determinant for the rate and the efficiency of the primary reaction. }
}

@Article{HU_2004_Helbing_a,
  Title                    = {{A fast photoswitch for minimally perturbed peptides: investigation of the trans-->cis photoisomerization of N-methylthioacetamide.}},
  Author                   = {Helbing, Jan and Bregy, Harald and Bredenbeck, Jens and Pfister, Rolf and Hamm, Peter and Huber, Robert and Wachtveitl, Josef and {De Vico}, Luca and Olivucci, Massimo},
  Journal                  = {Journal of the American Chemical Society},
  Year                     = {2004},

  Month                    = jul,
  Number                   = {28},
  Pages                    = {8823--34},
  Volume                   = {126},

  Doi                      = {10.1021/ja049227a},
  ISSN                     = {0002-7863},
keywords = {AG-Huber},
  Url                      = {http://pubs.acs.org/doi/abs/10.1021/ja049227a}
}

@inproceedings{10.1117/12.506722,
author = {Robert Huber and Jacques E. Moser and Michael Gratzel and Josef L. Wachtveitl},
title = {{Beyond vibrationally mediated electron transfer: interfacial charge injection on a sub-10-fs time scale}},
volume = {5223},
booktitle = {Physical Chemistry of Interfaces and Nanomaterials II},
editor = {Tianquan Lian and Hai-Lung Dai},
organization = {International Society for Optics and Photonics},
publisher = {SPIE},
pages = {121 -- 131},
abstract = {The electron transfer (ET) from organic dye molecules to semiconductor-colloidal systems is characterized by a special energetic situation with a charge transfer reaction from a system of discrete donor levels to a continuum of acceptor states. If these systems show a strong electronic coupling they are amongst the fastest known ET systems with transfer times of less than 10 fs. In the first part a detailed discussion of the direct observation of an ET reaction with a time constant of about 6 fs will be given, with an accompanying argumentation concerning possible artifacts or other interfering signal contributions. In a second part we will try to give a simple picture for the scenario of such superfast ET reactions and one main focus will be the discussion of electronic dephasing and its consequences for the ET reaction. The actual ET process can be understood as a kind of dispersion process of the initially located electron into the colloid representing a real motion of charge density from the alizarin to the colloid.},
keywords = {electron transfer, ultrafast, femtosecond, dye, semiconductor, titanium dioxide},
year = {2003},
doi = {10.1117/12.506722},
URL = {https://doi.org/10.1117/12.506722}
}

@INPROCEEDINGS{1314015,
  author={Huber, R. and Moser, J.E. and Grutzet, M. and Wachtveitl, J.},
  booktitle={2003 European Quantum Electronics Conference. EQEC 2003 (IEEE Cat No.03TH8665)}, 
  title={Beyond vibrationally mediated electron transfer: coherent phenomena in a sub-10-femtosecond reaction regime}, 
  year={2003},
  volume={},
  number={},
  pages={158-},
  abstract={This study investigates the systems alizarin as well as coumarin 343 coupled onto TiO/sub 2/ nanoparticles with a femtosecond pump/probe setup. The investigation applies sub 20 fs pump pulses, provided by a noncollinear optical parametric amplifier (NOPA) and a supercontinuum generated in CaF/sub 2/ for a ultrabroadband detection covering a spectral range from 300-960 nm. This work also studies coherent wavepacket propagation succeeding electron transfer at the two systems alizarin/coumarin on TiO/sub 2/. Due to the superfast time scale of the investigated electron transfer (ET) reactions of about 4-7 fs the systems show fundamental differences to conventional molecular ET systems. The ET process is no longer mediated by molecular vibrations and therefore classical molecular ET theories lose their applicability. Results show the real-time coherent excitation of molecular vibrational eigenmodes directly by the ET reaction as well as the generation of phonons during polaron formation in the TiO/sub 2/ lattice. The presented investigations in combination with the classification of the appearing mechanisms could be the basis for an extension of molecular ET theories to superfast systems typically found at molecule/solid state interfaces.},
  keywords={},
  doi={10.1109/EQEC.2003.1314015},
  ISSN={},
  month={June},}

@article{HUBER200239,
title = {Observation of photoinduced electron transfer in dye/semiconductor colloidal systems with different coupling strengths},
journal = {Chemical Physics},
volume = {285},
number = {1},
pages = {39-45},
year = {2002},
note = {Unconventional Photoactive Systems},
issn = {0301-0104},
doi = {https://doi.org/10.1016/S0301-0104(02)00687-0},
url = {https://www.sciencedirect.com/science/article/pii/S0301010402006870},
author = {Robert Huber and Jacques E Moser and Michael Grätzel and Josef Wachtveitl},
abstract = {Investigations on the ultrafast electron injection and recombination mechanism from the dyes alizarin and coumarin 343 to wide band gap semiconductor colloids in solution are presented, combined with detailed studies on population, depopulation and relaxation phenomena. We discuss transient absorption measurements on time scales from 100 fs to >1 ns throughout the visible spectral range (350–650 nm), allowing the simultaneous time resolved observation of signals assigned to ground state, cation and injected electron in the conduction band of the semiconductor. Analysis of transient absorption changes in the near UV region, where cation absorption is dominant, allows unambiguous assignment of the various kinetic components. This facilitates the distinction between the different contributions of the various absorbing species also in the congested visible spectral range. Comparison between the two dyes with respect to their different electron transfer parameters provides a direct way to analyze the influence of the electronic coupling element V on the injection and recombination process. Detailed inspection of the decay related spectra for both samples yields information on the environmental response succeeding the cation formation.}
}

@PhdThesis{HU_2002_Huber_c,
  Title = {{Elektronentransfer an Farbstoff-Halbleiter-Grenzfl\"{a}chen}},
  Author = {Huber, Robert},
  School = {Ludwig-Maximilians-Universit\"{a}t M\"{u}nchen},
  Year = {2002},
  keywords = {AG-Huber},
  Publisher = {Ludwig-Maximilians-Universit\"{a}t M\"{u}nchen},
  Url = {http://edoc.ub.uni-muenchen.de/93/1/Huber_Robert.pdf}
}

@Article{HU_2002_Huber_a,
  Title                    = {{Real-Time Observation of Photoinduced Adiabatic Electron Transfer in Strongly Coupled Dye/Semiconductor Colloidal Systems with a 6 fs Time Constant}},
  Author                   = {Huber, Robert and Moser, Jacques-E. and Gr\"{a}tzel, Michael and Wachtveitl, Josef},
  Journal                  = {The Journal of Physical Chemistry B},
  Year                     = {2002},

  Month                    = jun,
  Number                   = {25},
  Pages                    = {6494--6499},
  Volume                   = {106},
keywords = {AG-Huber},

  Doi                      = {10.1021/jp0155819},
  ISSN                     = {1520-6106},
  Url                      = {http://pubs.acs.org/doi/abs/10.1021/jp0155819}
}

@inproceedings{Huber:02,
author = {Robert Huber and Jacques E. Moser and Michael Gr\"{a}tzel and Josef Wachtveitl},
booktitle = {The Thirteenth International Conference on Ultrafast Phenomena},
journal = {The Thirteenth International Conference on Ultrafast Phenomena},
keywords = {Spectroscopy, surface; Femtosecond phenomena; Molecules; Pump probe spectroscopy; Semiconductors; Solar energy; Temporal resolution; Titanium dioxide},
pages = {ThC5},
publisher = {Optica Publishing Group},
title = {Photoinduced electron transfer in dye/semiconductor systems on a sub-10-fs time scale},
year = {2002},
url = {https://opg.optica.org/abstract.cfm?URI=UP-2002-ThC5},
doi = {10.1364/UP.2002.ThC5},
abstract = {Pump-probe investigation of alizarin adsorbed on the surface of TiO2 colloids reveals a 6 femtosecond electron transfer from the dye molecule to the semiconductor surface, allowing to identify the key factors for this ultrafast electron transfer.},
}

@article{HUBER2001443,
title = {Noncollinear optical parametric amplifiers with output parameters improved by the application of a white light continuum generated in CaF2},
journal = {Optics Communications},
volume = {194},
number = {4},
pages = {443-448},
year = {2001},
issn = {0030-4018},
doi = {https://doi.org/10.1016/S0030-4018(01)01324-4},
url = {https://www.sciencedirect.com/science/article/pii/S0030401801013244},
author = {Robert Huber and Helmut Satzger and Wolfgang Zinth and Josef Wachtveitl},
keywords = {Femtosecond pulses, Parametric amplification, White light continuum, Supercontinuum, Frequency conversion, Amplification bandwidth, Calcium fluoride (CaF)},
abstract = {We report the drastic improvement of output parameters of femtosecond noncollinear optical parametric amplifiers by applying supercontinuum seed pulses generated in CaF2 instead of sapphire and imaging via all reflective optics. Features of the setup are broad amplification bandwidths up to 310 THz (470–910 nm), an almost Gaussian beam profile, a divergence with M2 factor of less than 1.4, pulse to pulse energy fluctuations of less than 2.5% and compressibility of the pulses down to 16 fs. The high intensity of the supercontinuum seed pulse (80 nJ) yields a quantum efficiency for the conversion of pump to signal of more than 30%. Even for short wavelengths e.g. at 470 nm pulse energies above 30 μJ were obtained for 110 μJ of 400 nm pump light.}
}

@Article{HU_2000_Huber_a,
  Title                    = {{The Role of Surface States in the Ultrafast Photoinduced Electron Transfer from Sensitizing Dye Molecules to Semiconductor Colloids}},
  Author                   = {Huber, Robert and Sp\"{o}rlein, Sebastian and Moser, Jacques E and Gr\"{a}tzel, Michael and Wachtveitl, Josef},
  Journal                  = {The Journal of Physical Chemistry B},
  Year                     = {2000},

  Month                    = sep,
  Number                   = {38},
  Pages                    = {8995--9003},
  Volume                   = {104},
keywords = {AG-Huber},

  Doi                      = {10.1021/jp9944381},
  ISSN                     = {1520-6106},
  Publisher                = {American Chemical Society},
  Url                      = {http://pubs.acs.org/doi/abs/10.1021/jp9944381}
}

@InProceedings{10.1007/978-3-642-56546-5_133,
author="Huber, Robert
and Sp{\"o}rlein, Sebastian
and Moser, Jacques E.
and Gr{\"a}tzel, Michael
and Wachtveitl, Josef",
title="Surface States Control Ultrafast Electron Injection in Dye/Semiconductor Colloidal Systems",
booktitle="Ultrafast Phenomena XII",
year="2001",
publisher="Springer Berlin Heidelberg",
address="Berlin, Heidelberg",
pages="456--458",
abstract="Electron injection from photoexcited dye molecules into semiconductor colloidal particles (TiO2 and ZrO2) is investigated by femtosecond (fs) spectroscopy. Ultrafast reaction dynamics in the dye/ZrO2-system with an inaccessible conduction band demonstrates efficient electron transfer to surface defect states.",
isbn="978-3-642-56546-5"
}

@Article{HU_1999_Wachtveitl_a,
  Title                    = {{Ultrafast photoinduced electron transfer in coumarin 343 sensitized TiO2-colloidal solution}},
  Author                   = {Wachtveitl, Josef and Huber, Robert and Sp\"{o}rlein, Sebastian and Moser, Jacques E and Gr\"{a}tzel, Michael},
  Journal                  = {International Journal of Photoenergy},
  Year                     = {1999},
  Number                   = {3},
  Pages                    = {153--155},
  Volume                   = {1},
keywords = {AG-Huber},

  Doi                      = {10.1155/S1110662X99000264},
  ISSN                     = {1110-662X},
  Url                      = {http://www.hindawi.com/journals/ijp/1999/418298/abs/}
}