1. Articles from Thomas Klein

    1-24 of 34 1 2 »
    1. OptoRes presents world-record 3 MHz swept laser at SPIE BiOS / Photonics West in San Francisco

      OptoRes presents world-record 3 MHz swept laser at SPIE BiOS / Photonics West in San Francisco

      Ideally suited for optical coherence tomography, Optores‘ FDML laser with 3 MHz sweep rate is more than 10x faster than competition. Optores GmbH announces the latest upgrade to its NG-FDML series of wavelength-swept lasers. The SPIE Photonics West conference marks the launch of the new 3 MHz imaging speed option: Double as fast as previously, and more than 10x faster than any other commercially available swept laser. The new device is ideal for optical coherence tomography (OCT) in medicine, biology and industrial inspection. “Multi-MHz sweep rates are necessary for high-resolution 4D-OCT, which shows three-dimensional tissue structure live and in real ...

      Read Full Article
    2. Swept source OCT system and method with phase-locked detection

      Swept source OCT system and method with phase-locked detection

      A swept source OCT system and related method are disclosed. The system comprises a control device for operating a tunable light source in response to an electronic sweep control signal such that the tunable light source carries out wave length sweeps with a repetition rate f.sub.sweep, which depends on the frequency of the sweep control signal. The system further comprises a detection device for the time-resolved detection of an interference signal from a sample beam and a reference beam with the help of a detection cycle signal. The sweep control signal and the detection cycle signal are phase-locked ...

      Read Full Article
    3. Method for reducing the dimensionality of a spatially registered signal derived from the optical properties of a sample, and device therefor

      Method for reducing the dimensionality of a spatially registered signal derived from the optical properties of a sample, and device therefor

      At least one embodiment of the method is designed to create a two-dimensional image of a three-dimensional sample. The method comprises the following steps: provision of a wave-length-tunable light source (1) that emits primary radiation (P) with wavelengths that vary over time; sampling of location points of the sample (2) with the primary radiation (P); collection of secondary radiation (S), wherein the secondary radiation (S) is a part of the primary radiation (P) reflected by the sample (2); creation of an interferometer-based detection signal for a plurality of sample areas, each with at least one location point, using a detection ...

      Read Full Article
    4. Analysis of FDML lasers with meter range coherence

      Analysis of FDML lasers with meter range coherence

      FDML lasers provide sweep rates in the MHz range at wide optical bandwidths, making them ideal sources for high speed OCT. Recently, at lower speed, ultralong-range swept-source OCT has been demonstrated using a tunable vertical cavity surface emitting laser (VCSEL) and also using a Vernier-tunable laser. These sources provide relatively high sweep rates and meter range coherence lengths. In order to achieve similar coherence, we developed an extremely well dispersion compensated Fourier Domain Mode Locked (FDML) laser, running at 3.2 MHz sweep rate and 120 nm spectral bandwidth. We demonstrate that this laser offers meter range coherence and enables ...

      Read Full Article
    5. High-speed OCT light sources and systems [Invited]

      High-speed OCT light sources and systems [Invited]

      Imaging speed is one of the most important parameters that define the performance of optical coherence tomography (OCT) systems. During the last two decades, OCT speed has increased by over three orders of magnitude. New developments in wavelength-swept lasers have repeatedly been crucial for this development. In this review, we discuss the historical evolution and current state of the art of high-speed OCT systems, with focus on wavelength swept light sources and swept source OCT systems.

      Read Full Article
    6. Flexible A-scan rate MHz OCT: computational downscaling by coherent averaging

      Flexible A-scan rate MHz OCT: computational downscaling by coherent averaging

      In order to realize fast OCT-systems with adjustable line rate, we investigate averaging of image data from an FDML based MHz-OCT-system. The line rate can be reduced in software and traded in for increased system sensitivity and image quality. We compare coherent and incoherent averaging to effectively scale down the system speed of a 3.2 MHz FDML OCT system to around 100 kHz in postprocessing. We demonstrate that coherent averaging is possible with MHz systems without special interferometer designs or digital phase stabilisation. We show OCT images of a human finger knuckle joint in vivo with very high quality ...

      Read Full Article
    7. Dynamical Fabry-Perot tuneable filter device

      Dynamical Fabry-Perot tuneable filter device

      A Fabry-Perot tuneable filter device is described with reflecting elements separated by an optical path length to form an optical resonator cavity. A first actuator means is directly or indirectly coupled with a first reflecting element. And the first actuator means is configured to modulate the optical path length between first and second reflecting elements by a modulation amplitude to thereby sweep the optical resonator cavity through a band of optical resonance frequencies with a sweep frequency of 70 kHz or more. And the mechanical coupling between selected elements of the arrangement is sufficiently low such that when operated at ...

      Read Full Article
    8. Combined 60° Wide-Field Choroidal Thickness Maps and High-Definition En Face Vasculature Visualization Using Swept-Source Megahertz OCT at 1050 nm

      Combined 60° Wide-Field Choroidal Thickness Maps and High-Definition En Face Vasculature Visualization Using Swept-Source Megahertz OCT at 1050 nm

      Purpose : To demonstrate ultrahigh-speed swept-source optical coherence tomography (SS-OCT) at 1.68 million A-scans/s for choroidal imaging in normal and diseased eyes over a ∼60° field of view. To investigate and correlate wide-field three-dimensional (3D) choroidal thickness (ChT) and vascular patterns using ChT maps and coregistered high-definition en face images extracted from a single densely sampled Megahertz-OCT (MHz-OCT) dataset. Methods : High-definition, ∼60° wide-field 3D datasets consisting of 2088 × 1024 A-scans were acquired using a 1.68 MHz prototype SS-OCT system at 1050 nm based on a Fourier-domain mode-locked laser. Nine subjects (nine eyes) with various chorioretinal diseases or without ...

      Read Full Article
    9. Feature Of The Week 7/6/2015: Ultra-Widefield Retinal MHz-OCT Imaging With up to 100 Degrees Viewing Angle

      Feature Of The Week 7/6/2015: Ultra-Widefield Retinal MHz-OCT Imaging With up to 100 Degrees Viewing Angle

      We evaluate strategies to maximize the field of view (FOV) of in vivo retinal OCT imaging of human eyes and analyze the problems caused by the increased scan angle. Three imaging modes are tested: Single volume imaging with 85° FOV as well as with 100° and stitching of five 60° images to a 100° mosaic (measured as usually from the nodal point). We employ a MHz-OCT system based on a 1060nm Fourier domain mode locked (FDML) laser with a depth scan rate of 1.68MHz. The high speed is essential for dense isotropic sampling of the large areas. Challenges caused ...

      Read Full Article
    10. Ultra-widefield retinal MHz-OCT imaging with up to 100 degrees viewing angle

      Ultra-widefield retinal MHz-OCT imaging with up to 100 degrees viewing angle

      We evaluate strategies to maximize the field of view (FOV) of in vivo retinal OCT imaging of human eyes. Three imaging modes are tested: Single volume imaging with 85° FOV as well as with 100° and stitching of five 60° images to a 100° mosaic (measured from the nodal point). We employ a MHz-OCT system based on a 1060nm Fourier domain mode locked (FDML) laser with a depth scan rate of 1.68MHz. The high speed is essential for dense isotropic sampling of the large areas. Challenges caused by the wide FOV are discussed and solutions to most issues are ...

      Read Full Article
    11. A Time-Encoded Technique for fibre-based hyperspectral broadband stimulated Raman microscopy

      A Time-Encoded Technique for fibre-based hyperspectral broadband stimulated Raman microscopy

      Raman sensing and microscopy are among the most specific optical technologies to identify the chemical compounds of unknown samples, and to enable label-free biomedical imaging. Here we present a method for stimulated Raman scattering spectroscopy and imaging with a time-encoded (TICO) Raman concept. We use continuous wave, rapidly wavelength-swept probe lasers and combine them with a short-duty-cycle actively modulated pump laser. Hence, we achieve high stimulated Raman gain signal levels, while still benefitting from the narrow linewidth and low noise of continuous wave operation. Our all-fibre TICO-Raman setup uses a Fourier domain mode-locked laser source to achieve a unique combination ...

      Read Full Article
    12. Optores Introduces OGOP – the Optores GPU OCT Processing Library

      Optores Introduces OGOP – the Optores GPU OCT Processing Library

      Optores proudly introduces OGOP – the Optores GPU OCT Processing library, an ultra-fast and highly reliable processing library for optical coherence tomography (OCT) data. Based on graphic-processing unit (GPU) optimized code, OGOP enables real-time OCT processing with sustained throughput of several gigabytes per second. The library can be licensed in editions with increasing feature sets and processing capabilities. It covers the whole OCT processing pipeline from raw data to image, and features future-proof cross-platform code. OGOP can been seen in action at Optores's new youtube channel . The video shows sustained and real-time volumetric OCT imaging with 20 entire volumes per ...

      Read Full Article
    13. A 4-D OCT Engine with 1 GVoxel/s

      A 4-D OCT Engine with 1 GVoxel/s

      Optical coherence tomography (OCT) is a depth-resolved imaging modality that provides micrometer-scale cross-sectional and 3-D information on the scattering properties of biological samples. 1 Video rate real-time 3-D volumetric OCT (4-D-OCT) could generate a new class of optical tools in clinical practice, like surgical guidance. 2 This challenge requires us to combine a high-speed OCT imaging setup, ultrafast data acquisition and adequate real-time data processing to process and visualize the vast amount of data. Although 4-D-OCT has long been a dream for researchers, only a few groups have successfully implemented 4-D volumetric OCT imaging with real-time visualization—usually with low ...

      Read Full Article
    14. High definition live 3D-OCT in vivo: design and evaluation of a 4D OCT engine with 1 GVoxel/s

      High definition live 3D-OCT in vivo: design and evaluation of a 4D OCT engine with 1 GVoxel/s

      We present a 1300 nm OCT system for volumetric real-time live OCT acquisition and visualization at 1 billion volume elements per second. All technological challenges and problems associated with such high scanning speed are discussed in detail as well as the solutions. In one configuration, the system acquires, processes and visualizes 26 volumes per second where each volume consists of 320 x 320 depth scans and each depth scan has 400 usable pixels. This is the fastest real-time OCT to date in terms of voxel rate. A 51 Hz volume rate is realized with half the frame number. In both ...

      Read Full Article
    15. Megahertz ultra-wide-field swept-source retina optical coherence tomography compared to current existing imaging devices

      Megahertz ultra-wide-field swept-source retina optical coherence tomography compared to current existing imaging devices

      Background To investigate the image quality of wide-angle cross-sectional and reconstructed fundus images based on ultra-megahertz swept-source Fourier domain mode locking (FDML) OCT compared to current generation diagnostic devices. Methods A 1,050 nm swept-source FDML OCT system was constructed running at 1.68 MHz A-scan rate covering approximately 70° field of view. Twelve normal eyes were imaged with the device applying an isotropically dense sampling protocol (1,900 × 1,900 A-scans) with a fill factor of 100 %. Obtained OCT scan image quality was compared with two commercial OCT systems (Heidelberg Spectralis and Stratus OCT) of the same 12 eyes ...

      Read Full Article
    16. Multi-MHz retinal OCT

      Multi-MHz retinal OCT

      We analyze the benefits and problems of in vivo optical coherence tomography (OCT) imaging of the human retina at A-scan rates in excess of 1 MHz, using a 1050 nm Fourier-domain mode-locked (FDML) laser. Different scanning strategies enabled by MHz OCT line rates are investigated, and a simple multi-volume data processing approach is presented. In-vivo OCT of the human ocular fundus is performed at different axial scan rates of up to 6.7 MHz. High quality non-mydriatic retinal imaging over an ultra-wide field is achieved by a combination of several key improvements compared to previous setups. For the FDML laser ...

      Read Full Article
    17. Feature Of The Week 6/23/13: Ludwig Maximilian University of Munich Investigates Benefits of Joint Aperture Detection in Ophthalmic MHz OCT

      Feature Of The Week 6/23/13: Ludwig Maximilian University of Munich Investigates Benefits of Joint Aperture Detection in Ophthalmic MHz OCT

      Joint-aperture optical coherence tomography (JA-OCT) is an angle-resolved OCT method, in which illumination from an active channel is simultaneously probed by several passive channels. JA-OCT increases the collection efficiency and effective sensitivity of the OCT system without increasing the power on the sample. Additionally, JA-OCT provides angular scattering information about the sample in a single acquisition, so the OCT imaging speed is not reduced. Thus, JA-OCT is especially suitable for ultra high speed in-vivo imaging. JA-OCT is compared to other angle-resolved techniques, and the relation between joint aperture imaging, adaptive optics, coherent and incoherent compounding is discussed. We present angle-resolved ...

      Read Full Article
    18. Picosecond pulses from wavelength-swept continuous-wave Fourier domain mode-locked lasers

      Picosecond pulses from wavelength-swept continuous-wave Fourier domain mode-locked lasers

      Ultrafast lasers have a crucial function in many fields of science; however, up to now, high-energy pulses directly from compact, efficient and low-power semiconductor lasers are not available. Therefore, we introduce a new approach based on temporal compression of the continuous-wave, wavelength-swept output of Fourier domain mode-locked lasers, where a narrowband optical filter is tuned synchronously to the round-trip time of light in a kilometre-long laser cavity. So far, these rapidly swept lasers enabled orders-of-magnitude speed increase in optical coherence tomography. Here we report on the generation of ~60-70 ps pulses at 390 kHz repetition rate. As energy is stored ...

      Read Full Article
    19. Joint aperture detection for speckle reduction and increased collection efficiency in ophthalmic MHz OCT

      Joint aperture detection for speckle reduction and increased collection efficiency in ophthalmic MHz OCT

      Joint-aperture optical coherence tomography (JA-OCT) is an angle-resolved OCT method, in which illumination from an active channel is simultaneously probed by several passive channels. JA-OCT increases the collection efficiency and effective sensitivity of the OCT system without increasing the power on the sample. Additionally, JA-OCT provides angular scattering information about the sample in a single acquisition, so the OCT imaging speed is not reduced. Thus, JA-OCT is especially suitable for ultra high speed in-vivo imaging. JA-OCT is compared to other angle-resolved techniques, and the relation between joint aperture imaging, adaptive optics, coherent and incoherent compounding is discussed. We present angle-resolved ...

      Read Full Article
    20. Retinal polarization-sensitive optical coherence tomography at 1060 nm with 350 kHz A-scan rate using an Fourier domain mode locked laser

      Retinal polarization-sensitive optical coherence tomography at 1060 nm with 350 kHz A-scan rate using an Fourier domain mode locked laser

      We present a novel, high-speed, polarization-sensitive, optical coherence tomography set-up for retinal imaging operating at a central wavelength of 1060 nm which was tested for in vivo imaging in healthy human volunteers. We use the system in combination with a Fourier domain mode locked laser with active spectral shaping which enables the use of forward and backward sweep in order to double the imaging speed without a buffering stage. With this approach and with a custom designed data acquisition system, we show polarization-sensitive imaging with an A-scan rate of 350 kHz. The acquired three-dimensional data sets of healthy human volunteers ...

      Read Full Article
    21. Extended coherence length megahertz FDML and its application for anterior segment imaging

      Extended coherence length megahertz FDML and its application for anterior segment imaging
      We present a 1300 nm Fourier domain mode locked (FDML) laser for optical coherence tomography (OCT) that combines both, a high 1.6 MHz wavelength sweep rate and an ultra-long instantaneous coherence length for rapid volumetric deep field imaging. By reducing the dispersion in the fiber delay line of the FDML laser, the instantaneous coherence length and hence the available imaging range is approximately quadrupled compared to previously published MHz-FDML setups, the imaging speed is increased by a factor of 16 compared to previous extended coherence length results. We present a detailed characterization of the FDML laser performance. We demonstrate ...
      Read Full Article
    22. Ultrahigh-speed non-invasive widefield angiography

      Ultrahigh-speed non-invasive widefield angiography

      tinal and choroidal vascular imaging is an important diagnostic benefit for ocular diseases such as age-related macular degeneration. The current gold standard for vessel visualization is fluorescence angiography. We present a potential non-invasive alternative to image blood vessels based on functional Fourier domain optical coherence tomography (OCT). For OCT to compete with the field of view and resolution of angiography while maintaining motion artifacts to a minimum, ultrahigh-speed imaging has to be introduced. We employ Fourier domain mode locking swept source technology that offers high quality imaging at an A-scan rate of up to 1.68 MHz. We present retinal ...

      Read Full Article
    23. High-speed polarization-sensitive OCT at 1060 nm using a Fourier domain mode-locked swept source

      High-speed polarization-sensitive OCT at 1060 nm using a Fourier domain mode-locked swept source

      Optical coherence tomography (OCT) in the 1060nm range is interesting for in vivo imaging of the human posterior eye segment (retina, choroid, sclera), as it permits a long penetration depth. Complementary to structural images, polarization-sensitive OCT (PS-OCT) images visualize birefringent, polarization-maintaining or depolarizing areas within the sample. This information can be used to distinguish retinal layers and structures with different polarization properties. High imaging speed is crucial for imaging ocular structures in vivo in order to minimize motion artifacts while acquiring sufficiently large datasets. Here, we demonstrate PS-OCT imaging at 350 kHz A-scan rate using a two-channel PS-OCT system in ...

      Read Full Article
    24. Broadband Fourier domain mode-locked laser for optical coherence tomography at 1060 nm

      Broadband Fourier domain mode-locked laser for optical coherence tomography at 1060 nm

      Optical coherence tomography (OCT) in the 1060nm range is interesting for in vivo imaging of the human posterior eye segment (retina, choroid, sclera) due to low absorption in water and deep penetration into the tissue. Rapidly tunable light sources, such as Fourier domain mode-locked (FDML) lasers, enable acquisition of densely sampled three-dimensional datasets covering a wide field of view. However, semiconductor optical amplifiers (SOAs)-the typical laser gain media for swept sources-for the 1060nm band could until recently only provide relatively low output power and bandwidth. We have implemented an FDML laser using a new SOA featuring broad gain bandwidth ...

      Read Full Article
    1-24 of 34 1 2 »
  1. Categories

    1. Applications:

      Art, Cardiology, Dentistry, Dermatology, Developmental Biology, Gastroenterology, Gynecology, Microscopy, NDE/NDT, Neurology, Oncology, Ophthalmology, Other Non-Medical, Otolaryngology, Pulmonology, Urology
    2. Business News:

      Acquisition, Clinical Trials, Funding, Other Business News, Partnership, Patents
    3. Technology:

      Broadband Sources, Probes, Tunable Sources
    4. Miscellaneous:

      Jobs & Studentships, Student Theses, Textbooks
  2. Topics in the News

    1. (33 articles) Thomas Klein
    2. (32 articles) Robert A. Huber
    3. (31 articles) Wolfgang Wieser
    4. (28 articles) Ludwig Maximilian University of Munich
    5. (14 articles) Benjamin R. Biedermann
    6. (12 articles) Christoph M. Eigenwillig
    7. (10 articles) University of Lübeck
    8. (7 articles) Aljoscha S. Neubauer
    9. (6 articles) Tom Pfeiffer
    10. (5 articles) Anselm Kampik
    11. (1 articles) Academic Hospital Maastricht
  3. Popular Articles

  4. Picture Gallery

    FDML swept source at 1060 nm using a tapered amplifier Multi-Megahertz OCT: High quality 3D imaging at 20 million A-scans and 4.5 GVoxels per second Feature Of The Week 9/5/10: Record Breaking OCT Volumetric Image Acquisition Rates by Researchers at Ludwig Maximilians University Wavelength swept amplified spontaneous emission source for high speed retinal optical coherence tomography at 1060 nm Megahertz OCT for ultrawide-field retinal imaging with a 1050nm Fourier domain mode-locked laser Feature Of The Week 9/4/11: Researchers at Ludwig-Maximilians University Continue to Blaze Trails Developing High Performance Swept Source OCT Technology and Its Application in Medical Imaging High-speed polarization-sensitive OCT at 1060 nm using a Fourier domain mode-locked swept source Ultrahigh-speed non-invasive widefield angiography Feature Of The Week 7/6/2015: Ultra-Widefield Retinal MHz-OCT Imaging With up to 100 Degrees Viewing Angle (Cost)-Effectiveness of OCT in BCC (ROCTI) Precision analysis and optimization in phase decorrelation OCT velocimetry Image-guided vibrometry system integrated with spectral- and time-domain optical coherence tomography