1. Articles from Wolfgang Draxinger

    1-8 of 8
    1. High-speed fiber scanning endoscope for volumetric multi-megahertz optical coherence tomography

      High-speed fiber scanning endoscope for volumetric multi-megahertz optical coherence tomography

      We present a forward-viewing fiber scanning endoscope (FSE) for high-speed volumetric optical coherence tomography (OCT). The reduction in size of the probe was achieved by substituting the focusing optics by an all-fiber-based imaging system which consists of a combination of scanning single-mode fibers, a glass spacer, made from a step-index multi-mode fiber, and a gradient-index fiber. A lateral resolution of 11 μm was achieved at a working distance of 1.2 mm. The newly designed piezo-based FSE has an outer diameter of 1.6 mm and a rigid length of 13.5 mm. By moving the whole imaging optic in ...

      Read Full Article
    2. Ultra low noise Fourier domain mode locked laser for high quality megahertz optical coherence tomography

      Ultra low noise Fourier domain mode locked laser for high quality megahertz optical coherence tomography

      We investigate the origin of high frequency noise in Fourier domain mode locked (FDML) lasers and present an extremely well dispersion compensated setup which virtually eliminates intensity noise and dramatically improves coherence properties. We show optical coherence tomography (OCT) imaging at 3.2 MHz A-scan rate and demonstrate the positive impact of the described improvements on the image quality. Especially in highly scattering samples, at specular reflections and for strong signals at large depth, the noise in optical coherence tomography images is significantly reduced. We also describe a simple model that suggests a passive physical stabilizing mechanism that leads to ...

      Read Full Article
    3. Feature Of The Week 09/10/2017: Thermo-elastic Optical Coherence Tomography

      Feature Of The Week 09/10/2017: Thermo-elastic  Optical Coherence Tomography

      The conventional OCT image contrast is derived from elastic scattering, and shows the internal structure of the sample. The determination of the tissue type in OCT images usually depends on the interpretation by the image reader. More accurate tissue type contrast may be achieved by new OCT-based imaging modalities, with sensitivity to other physical parameters than scattering alone. Phase-sensitive OCT can detect tissue motion on nanometer-to- micrometer length scales using the phase of the OCT signal. Depending on the nature of the excitation, different functional images can be reconstructed: a mechanical stimulus yields images of tissue elasticity (optical coherence elastography ...

      Read Full Article
    4. Thermo-elastic optical coherence tomography

      Thermo-elastic optical coherence tomography

      The absorption of nanosecond laser pulses induces rapid thermo-elastic deformation in tissue. A sub-micrometer scale displacement occurs within a few microseconds after the pulse arrival. In this Letter, we investigate the laser-induced thermo-elastic deformation using a 1.5 MHz phase-sensitive optical coherence tomography (OCT) system. A displacement image can be reconstructed, which enables a new modality of phase-sensitive OCT, called thermo-elastic OCT. An analysis of the results shows that the optical absorption is a dominating factor for the displacement. Thermo-elastic OCT is capable of visualizing inclusions that do not appear on the structural OCT image, providing additional tissue type information.

      Read Full Article
    5. 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
    6. 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
    7. 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
    8. 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
    1-8 of 8
  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. (8 articles) University of Lübeck
    2. (8 articles) Robert A. Huber
    3. (7 articles) Tom Pfeiffer
    4. (6 articles) Wolfgang Wieser
    5. (4 articles) Thomas Klein
    6. (4 articles) Optores
    7. (3 articles) Ludwig Maximilian University of Munich
    8. (2 articles) Delft University of Technology
    9. (2 articles) Erasmus University
    10. (2 articles) Tianshi Wang
    11. (1 articles) Institute of Applied Physics
    12. (1 articles) Medical University of Vienna
    13. (1 articles) Kyungpook National University
    14. (1 articles) Singapore Eye Research Institute
    15. (1 articles) University of Western Australia
    16. (1 articles) Stefan G. Sacu
    17. (1 articles) Brendan F. Kennedy
    18. (1 articles) Yongyang Huang
    19. (1 articles) Jeehyun Kim
    20. (1 articles) Ursula Schmidt-Erfurth
  3. Popular Articles

  4. Picture Gallery

    High definition live 3D-OCT in vivo: design and evaluation of a 4D OCT engine with 1 GVoxel/s A 4-D OCT Engine with 1 GVoxel/s Combined 60° Wide-Field Choroidal Thickness Maps and High-Definition En Face Vasculature Visualization Using Swept-Source Megahertz OCT at 1050 nm Analysis of FDML lasers with meter range coherence Thermo-elastic optical coherence tomography Feature Of The Week 09/10/2017: Thermo-elastic  Optical Coherence Tomography Ultra low noise Fourier domain mode locked laser for high quality megahertz optical coherence tomography High-speed fiber scanning endoscope for volumetric multi-megahertz optical coherence tomography Full-range space-division multiplexing optical coherence tomography angiography Measuring 3D Optic Nerve Head Deformations using Digital Volume Correlation of in vivo Optical Coherence Tomography Data (Thesis) Optical coherence tomography for characterization of nanocomposite materials (Thesis) In Vivo Corneal Microstructural Changes in Herpetic Stromal Keratitis: A Spectral-Domain Optical Coherence Tomography Analysis