@inbook{Hillmann2019,
   author = {Hillmann, Dierck;Pfäffle, Clara;Spahr, Hendrik;Sudkamp, Helge;Franke, Gesa and Hüttmann, Gereon},
   title = {In Vivo FF-SS-OCT Optical Imaging of Physiological Responses to Photostimulation of Human Photoreceptor Cells},
   booktitle = {High Resolution Imaging in Microscopy and Ophthalmology: New Frontiers in Biomedical Optics},
   editor = {Bille, Josef F.},
   publisher = {Springer International Publishing},
   address = {Cham},
   pages = {181-194},
   ISBN = {978-3-030-16638-0},
   
   url = {https://doi.org/10.1007/978-3-030-16638-0_8},
   year = {2019},
   type = {Book Section}
}

@article{Hillmann2017,
   author = {Hillmann, D; Spahr, H; Sudkamp, H; Hain, C; Hinkel, L; Franke, G and Hüttmann, G},
   title = {Off-axis reference beam for full-field swept-source OCT and holoscopy},
   journal = {Opt Expr},
   
   pages = {27770-27784},
   DOI = {10.1364/OE.25.027770},
   year = {2017},
   type = {Journal Article}
}

@article{Pfäffle2017,
   author = {Pfäffle, Clara and Spahr, Hendrik and Hillmann, Dierck and Sudkamp, Helge and Franke, Gesa and Koch, Peter and Hüttmann, Gereon},
   title = {Reduction of frame rate in full-field swept-source optical coherence tomography by numerical motion correction [Invited]},
   journal = {Biomedical Optics Express},
   volume = {8},
   number = {3},
   pages = {1499-1511},
   keywords = {Image reconstruction-restoration
Optical coherence tomography},
   url = {http://www.osapublishing.org/boe/abstract.cfm?URI=boe-8-3-1499},
   year = {2017},
   type = {Journal Article}
}

@article{RN4897,
   author = {Sudkamp, Helge and Koch, Peter and Spahr, Hendrik and Hillmann, Dierck and Franke, Gesa and Münst, Michael and Reinholz, Fred and Birngruber, Reginald and Hüttmann, Gereon},
   title = {In-vivo retinal imaging with off-axis full-field time-domain optical coherence tomography},
   journal = {Optics Letters},
   volume = {41},
   number = {21},
   pages = {4987-4990},
   DOI = {10.1364/OL.41.004987},
   url = {http://ol.osa.org/abstract.cfm?URI=ol-41-21-4987},
   year = {2016},
   type = {Journal Article}
}

@article{Spahr2016,
   author = {Spahr, H. and Hillmann, D. and Hain, C. and Pfäffle, C. and Sudkamp, H. and Franke, G. and Koch, P. and Hüttmann, G.},
   title = {Darstellung von Blutfluss und Pulsation in retinalen Gefäßen mit Full-Field-Swept-Source-OCT},
   journal = {Klin Monatsbl Augenheilkd},
   volume = {233},
   number = {12},
   pages = {1324-1330},
   ISSN = {0023-2165},
   DOI = {10.1055/s-0042-120279},
   year = {2016},
   type = {Journal Article}
}

@article{Hillmann2016,
   author = {Hillmann, Dierck and Spahr, Hendrik and Hain, Carola and Sudkamp, Helge and Franke, Gesa and Pfäffle, Clara and Winter, Christian and Hüttmann, Gereon},
   title = {Aberration-free volumetric high-speed imaging of in vivo retina},
   journal = {Scientific Reports},
   volume = {6},
   pages = {1-11},
   url = {http://dx.doi.org/10.1038/srep35209},
   year = {2016},
   type = {Journal Article}
}

@article{Hillmann2016,
   author = {Hillmann, Dierck and Spahr, Hendrik and Pfäffle, Clara and Sudkamp, Helge and Franke, Gesa and Hüttmann, Gereon},
   title = {In vivo optical imaging of physiological responses to photostimulation in human photoreceptors},
   journal = {PNAS Early Edition},
   pages = {1-6},
   abstract = {Noninvasive functional imaging of molecular and cellular processes of vision may have immense impact on research and clinical diagnostics. Although suitable intrinsic optical signals (IOSs) have been observed ex vivo and in immobilized animals in vivo, detecting IOSs of photoreceptor activity in living humans was cumbersome and time consuming. Here, we observed clear spatially and temporally resolved changes in the optical path length of the photoreceptor outer segment as a response to an optical stimulus in the living human eye. To witness these changes, we evaluated phase data obtained with a parallelized and computationally aberration-corrected optical coherence tomography system. The noninvasive detection of optical path length changes shows neuronal photoreceptor activity of single cones in living human retina, and therefore, it may provide diagnostic options in ophthalmology and neurology and could provide insights into visual phototransduction in humans.},
   url = {http://www.pnas.org/content/early/2016/10/10/1606428113.abstract},
   year = {2016},
   type = {Journal Article}
}

@inproceedings{Spahr2016,
   author = {Spahr, Hendrik and Hillmann, Dierck and Hain, Carola and Pfäffle, Clara and Sudkamp, Helge and Franke, Gesa and Hüttmann, Gereon},
   title = {Imaging vascular dynamics in human retina using full-field swept-source optical coherence tomography (Conference Presentation)},
   volume = {9697},
   pages = {96970E-96970E-1},
   note = {10.1117/12.2214303},
   abstract = {We demonstrate a new non-invasive method to assess the functional condition of the retinal vascular system. Phase-sensitive full-field swept-source optical coherence tomography (PhS-FF-SS-OCT) is used to investigate retinal vascular dynamics at unprecedented temporal resolution. Motion of retinal tissue, that is induced by expansion of the vessels therein, is measured with an accuracy of about 10 nm. The pulse shape of arterial and venous pulsation, their temporal delay as well as the frequency dependent pulse propagation through the capillary bed are determined. For the first time, imaging speed and motion sensitivity are sufficient for a direct measurement of pulse waves propagating with more than 600 mm/s in retinal vessels of a healthy young subject.},
   url = {http://dx.doi.org/10.1117/12.2214303},
   type = {Conference Proceedings},
year = { 2016}
}

@article{Spahr2015,
   author = {Spahr, Hendrik and Hillmann, Dierck and Hain, Carola and Pfäffle, Clara and Sudkamp, Helge and Franke, Gesa and Hüttmann, Gereon},
   title = {Imaging pulse wave propagation in human retinal vessels using full-field swept-source optical coherence tomography},
   journal = {Optics Letters},
   volume = {40},
   number = {20},
   pages = {4771-4774},
   abstract = {We demonstrate a new noninvasive method to assess biomechanical properties of the retinal vascular system. Phase-sensitive full-field swept-source optical coherence tomography (PhS-FF-SS-OCT) is used to investigate retinal vascular dynamics at unprecedented temporal resolution. The motion of retinal tissue that is induced by expansion of the vessels therein is measured with an accuracy of about 10 nm. The pulse shapes of arterial and venous pulsations, their temporal delays, as well as the frequency-dependent pulse propagation through the capillary bed, are determined. For the first time, imaging speed and motion sensitivity are sufficient for a direct measurement of pulse waves propagating with more than 600 mm/s in retinal vessels of a healthy young subject.},
   keywords = {Optical coherence tomography
Ophthalmology
Time-resolved imaging
Functional monitoring and imaging},
   DOI = {10.1364/OL.40.004771},
   url = {http://ol.osa.org/abstract.cfm?URI=ol-40-20-4771},
   year = {2015},
   type = {Journal Article}
}

@article{Spahr2015,
   author = {Spahr, Hendrik and Hain, Carola and Sudkamp, Helge and Franke, Gesa and Hillmann, Dierck and Huttmann, Gereon},
   title = {Functional Microangiography of in vivo human retina by Full-Field OCT},
   journal = {Investigative Ophthalmology & Visual Science},
   volume = {56},
   number = {7},
   pages = {5974-5974},
   abstract = { PurposeOCT based functional microangiography of the retina requires high speed acquisition of a large number of volumetric datasets. Imaging speed of conventional scanning OCT devices is limited by the applicable radiant power and the mechanics used to scan the focused beam over the desired field of view. Full-Field Swept-Source OCT (FF-SS-OCT) resolves both issues, using an areal illumination, which dramatically increases the allowed amount of radiation, and an ultrafast camera for a highly parallelized acquisition.  MethodsThe retina of healthy volunteers was illuminated with wavelengths between 816 and 867 nm by the extended beam of a tunable laser (Broadsweeper, Superlum). Retinal irradiance was below the maximum permissable exposure (MPE). Light backscattered from the retina was imaged onto an ultrafast CMOS camera (SA-Z, Photron), where it interfered with an extended reference beam. From a series of interference images at different wavelengths, volumetric OCT images of the retina were reconstructed.  ResultsWe demonstrate in vivo retinal imaging at 9.9 billion voxels per second (40 million A-scans/s with 256 axial pixels). Sacrificing depth resolution by reducing the number of axial pixels, the A-scan rate was increased to more than 1 billion A-scans per second. FF-SS-OCT allowed imaging of all important retinal structures with good quality at unprecedented imaging speed (see fig. 1). Fast volumetric imaging at up to 3000 volumes/s was used to visualize small capillaries and to analyze the pulsation of retinal arteries and veins (see fig. 2). Imaging time for an area of 4 mm x 2 mm (896 x 368 A-scans) was only 316 µs. The high volume rate and the inherent phase stability enabled quantitative measurement of the change of retinal thickness due to blood pulsation with approx. 10 nm precision. A delay of the venous pulsation with respect to the arteries was observed (approx. 11 ms). The amplitudes of higher frequency components of the venous pulsation were considerably attenuated.  ConclusionsFF-SS-OCT provides fast volumetric imaging of the retina with good image quality. The capillary network can be analyzed with high spatial and temporal resolution. Analysis of retinal pulsation may provide information on pathological changes of vessels and capillaries. Angiographic OCT acquired with the FF-SS-OCT setup. Functional angiography showing the pulsation of retinal artery and vein.},
   ISSN = {1552-5783},
   url = {http://dx.doi.org/},
   year = {2015},
   type = {Journal Article}
}

@article{Hillmann2013,
   author = {Hillmann, Dierck and Franke, Gesa and Hinkel, Laura and Bonin, Tim and Koch, Peter and Hüttmann, Gereon},
   title = {Off-axis full-field swept-source optical coherence tomography using holographic refocusing},
   pages = {857104-857104},
   note = {10.1117/12.2006436},
   abstract = {We demonstrate a full-field swept-source OCT using an off-axis geometry of the reference illumination. By using holographic refocusing techniques, a uniform lateral resolution is achieved over the measurement depth of approximately 80 Rayleigh lengths. Compared to a standard on-axis setup, artifacts and autocorrelation signals are suppressed and the measurement depth is doubled by resolving the complex conjugate ambiguity. Holographic refocusing was done efficiently by Fourier-domain resampling as demonstrated before in inverse scattering and holoscopy. It allowed to reconstruct a complete volume with about 10μm resolution over the complete measurement depth of more than 10mm. Off-axis full-field swept-source OCT enables high measurement depths, spanning many Rayleigh lengths with reduced artifacts.},
   DOI = {10.1117/12.2006436},
   url = {http://dx.doi.org/10.1117/12.2006436},
   year = {2013},
   type = {Journal Article}
}

@article{Franke2013,
   author = {Franke, Gesa Lilith and Hillmann, Dierck and Lührs, Christian and Koch, Peter and Wollenzin, Jörn and Hüttmann, Gereon},
   title = {Towards microscopic resolution in holoscopy},
   pages = {85711O-85711O},
   note = {10.1117/12.2006806},
   abstract = {Holoscopy is a new imaging approach combining digital holography and full-field Fourier-domain optical coherence tomography. The interference pattern between light scattered by a sample and a defined reference wave is recorded and processed numerically. During reconstruction numerical refocusing is applied, overcoming the limitation of the focal depth and thus a uniform, diffraction limited lateral resolution over the whole measurement depth can be obtained. The advantage of numerical refocusing becomes especially significant for imaging at high numerical apertures (NAs). We use a high-resolution setup based on a Mach-Zehnder interferometer with an high-resolution microscope objective (NA = 0.75). For reliable reconstruction of a sample volume the Rayleigh length of the microscope objective and the axial resolution, given by the spectral range of the light source, need to be matched. For a 0.75 NA objective a tunable light source with a sweeping range of ! 300nm is required. Here we present as a first step a tunable Ti:sapphire laser with a tuning range of 187 nm. By characterizing the spectral properties of the Ti:sapphire laser and determining the axial point spread function we demonstrate the feasibility of this light source for high-resolution holoscopy.},
   DOI = {10.1117/12.2006806},
   url = {http://dx.doi.org/10.1117/12.2006806},
   year = {2013},
   type = {Journal Article}
}

@inproceedings{Fink2013,
   author = {Fink, Peer K and Hillmann, Dierck and Franke, Gesa L and Ramm, Dirk and Koch, P and Hüttmann, Gereon},
   title = {Stray light rejection by structured illumination},
   booktitle = {Studierendentagung},
   publisher = {Universität zu Lübeck},
   type = {Conference Proceedings},
year = { 2013}
}

@article{Hillmann2012,
   author={Hillmann, D.  and Bonin, T.  and Luhrs, C.  and Franke, G.  and Hagen-Eggert, M.  and Koch, P.  and Huttmann, G. },
   title={{{C}ommon approach for compensation of axial motion artifacts in swept-source {O}{C}{T} and dispersion in {F}ourier-domain {O}{C}{T}}},
   journal={Opt Express},
   year={2012},
   volume={20},
   number={6},
   pages={6761--6776},
   month={Mar}
}

@article{Hillmann2012,
   author = {Hillmann, Dierck and Bonin, Tim and Lührs, Christian and Franke, Gesa and Hagen-Eggert, Martin and Koch, Peter and Hüttmann, Gereon},
   title = {Common approach for compensation of axial motion artifacts in swept-source OCT and dispersion in Fourier-domain OCT},
   journal = {Opt. Express},
   volume = {20},
   number = {6},
   pages = {6761-6776},
   abstract = {Swept-source optical coherence tomography (SS-OCT) is sensitive to sample motion during the wavelength sweep, which leads to image blurring and image artifacts. In line-field and full-field SS-OCT parallelization is achieved by using a line or area detector, respectively. Thus, approximately 1000 lines or images at different wavenumbers are acquired. The sweep duration is identically with the acquisition time of a complete B-scan or volume, rendering parallel SS-OCT more sensitive to motion artifacts than scanning OCT. The effect of axial motion on the measured spectra is similar to the effect of non-balanced group velocity dispersion (GVD) in the interferometer arms. It causes the apparent optical path lengths in the sample arm to vary with the wavenumber. Here we propose the cross-correlation of sub-bandwidth reconstructions (CCSBR) as a new algorithm that is capable of detecting and correcting the artifacts induced by axial motion in line-field or full-field SS-OCT as well as GVD mismatch in any Fourier-domain OCT (FD-OCT) setup. By cross-correlating images which were reconstructed from a limited spectral range of the interference signal, a phase error is determined which is used to correct the spectral modulation prior to the calculation of the A-scans. Performance of the algorithm is demonstrated on in vivo full-field SS-OCT images of skin and scanning FD-OCT of skin and retina.},
   keywords = {Image reconstruction-restoration
Optical coherence tomography},
   year = {2012}
}

@article{Hillmann2012,
   author = {Hillmann, Dierck and Franke, Gesa and Lührs, Christian and Koch, Peter and Hüttmann, Gereon},
   title = {Efficient holoscopy image reconstruction},
   journal = {Opt. Express},
   volume = {20},
   number = {19},
   pages = {21247-21263},
   abstract = {Holoscopy is a tomographic imaging technique that combines digital holography and Fourier-domain optical coherence tomography (OCT) to gain tomograms with diffraction limited resolution and uniform sensitivity over several Rayleigh lengths. The lateral image information is calculated from the spatial interference pattern formed by light scattered from the sample and a reference beam. The depth information is obtained from the spectral dependence of the recorded digital holograms. Numerous digital holograms are acquired at different wavelengths and then reconstructed for a common plane in the sample. Afterwards standard Fourier-domain OCT signal processing achieves depth discrimination. Here we describe and demonstrate an optimized data reconstruction algorithm for holoscopy which is related to the inverse scattering reconstruction of wavelength-scanned full-field optical coherence tomography data. Instead of calculating a regularized pseudoinverse of the forward operator, the recorded optical fields are propagated back into the sample volume. In one processing step the high frequency components of the scattering potential are reconstructed on a non-equidistant grid in three-dimensional spatial frequency space. A Fourier transform yields an OCT equivalent image of the object structure. In contrast to the original holoscopy reconstruction with backpropagation and Fourier transform with respect to the wavenumber, the required processing time does neither depend on the confocal parameter nor on the depth of the volume. For an imaging NA of 0.14, the processing time was decreased by a factor of 15, at higher NA the gain in reconstruction speed may reach two orders of magnitude.},
   keywords = {Image processing
Optical coherence tomography
Digital holography},
   year = {2012}
}

@inproceedings{Franke-2012,
   author = {Franke, Gesa Lilith and Hillmann, Dierck and Claussen, Thorsten and Luhrs, Christian and Koch, Peter and Huttmann, Gereon},
   title = {High resolution holoscopy},
   editor = {Joseph, A. Izatt and James, G. Fujimoto and Valery, V. Tuchin},
   publisher = {SPIE},
   volume = {8213},
   pages = {821324},
URL = { https://doi.org/10.1117/12.911166},
year = { 2012}

}

@inproceedings{Bonin2011,
   author = {Bonin, Tim and Hagen-Eggert, Martin and Franke, Gesa and Koch, Peter and Huttmann, Gereon},
   title = {Ultra highspeed in-vivo Fourier domain full-field OCT of the human retina},
   editor = {James, G. Fujimoto and Joseph, A. Izatt and Valery, V. Tuchin},
   publisher = {SPIE},
   volume = {7889},
   pages = {788906},
year = { 2011}

}

@book{Bonin2010,
   author = {Bonin, T. and Franke, G. and Hagen-Eggert, M. and Koch, P. and Huttmann, G.},
   title = {In vivo Fourier-domain full-field OCT of the human retina with 1.5 million A-lines/s},
   publisher = {Opt Lett. 2010 Oct 15;35(20):3432-4. doi: 10.1364/OL.35.003432.},
   abstract = {In vivo full-field (FF) optical coherence tomography (OCT) images of human retina are presented by using a rapidly tunable laser source in combination with an ultra-high-speed camera. Fourier-domain FF-OCT provided a way to increase the speed of retinal imaging by parallel acquisition of A-scans. Reduced contrast caused by cross talk was observed only below the retinal pigment epithelium. With a 100Hz sweep rate, FF-OCT was fast enough to acquire OCT images with acceptable motion artifacts. FF-OCT allows ultrafast retinal imaging, boosting image speed by a lack of moving parts and a considerably higher irradiation power.},
  year={2010}
}