1. Wolfgang Wieser

    0 Comments Leave a Comment

    1-15 of 55 1 2 3 4 »
    1. Mentioned In 55 Articles

    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 ...
      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 ...
      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 ...
      Read Full Article
    5. 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 ...
      Read Full Article
    6. INTRAPAPILLARY PROLIFERATION IN OPTIC DISK PITS: Clinical Findings and Time-Related Changes

      INTRAPAPILLARY PROLIFERATION IN OPTIC DISK PITS: Clinical Findings and Time-Related Changes
      Purpose: To investigate the structural changes of intrapapillary proliferations associated with optic disk pits (ODPs) and optic disk pit maculopathy (ODP-M) using enhanced depth-spectral domain-optical coherence tomography (SD-EDI-OCT) and megahertz optical coherence tomography (MHz-OCT). Methods: Sixteen eyes of patients with ODPs were studied. Papillary and peripapillary areas were repeatedly examined with SD-EDI-OCT over time. To evaluate swept-source OCT, some of the patients additionally received MHz-OCT-imaging. Results: MHz-OCT or SD-EDI images ...
      Read Full Article
    7. 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 ...
      Read Full Article
    8. Heartbeat OCT and Motion-Free 3D In Vivo Coronary Artery Microscopy

      Heartbeat OCT and Motion-Free 3D In Vivo Coronary Artery Microscopy
      Intravascular optical coherence tomography (IV-OCT) has gained widespread use over the past few years, offering highly detailed images of coronary artery pathologies and interventions (1) . In contrast to the cross-sectional view, longitudinal sections and 3-dimensional (3D) renderings are affected by cardiac motion artifacts and undersampling, complicating interpretation and measurements (2) . We developed Heartbeat OCT, a new OCT method that achieves up to 4,000 frames/s imaging speed for isotropically ...
      Read Full Article
    9. 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 ...
      Read Full Article
    10. 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 ...
      Read Full Article
    11. Feature Of The Week 12/06/2015: Heartbeat Optical Coherence Tomography

      Feature Of The Week 12/06/2015: Heartbeat Optical Coherence Tomography
      Intravascular optical coherence tomography (IV-OCT) has gained widespread use over the past few years, offering highly detailed images of the coronary artery pathologies and interventions. In contrast to the cross-sectional view, longitudinal sections and three-dimensional (3D) renderings are affected by cardiac motion artifacts and undersampling, complicating interpretation and measurements. We developed Heartbeat OCT, a new OCT method that overcomes these issues. This study aims to demonstrate in vivo Heartbeat OCT ...
      Read Full Article
    12. Heartbeat OCT: in vivo intravascular megahertz-optical coherence tomography

      Heartbeat OCT: in vivo intravascular megahertz-optical coherence tomography
      Cardiac motion artifacts, non-uniform rotational distortion and undersampling affect the image quality and the diagnostic impact of intravascular optical coherence tomography (IV-OCT). In this study we demonstrate how these limitations of IV-OCT can be addressed by using an imaging system that we called Heartbeat OCT, combining a fast Fourier Domain Mode Locked laser, fast pullback, and a micromotor actuated catheter, designed to examine a coronary vessel in less than one ...
      Read Full Article
    13. 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 ...
      Read Full Article
    14. 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 ...
      Read Full Article
    15. 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 ...
      Read Full Article
    16. 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 ...
      Read Full Article
    17. 1-15 of 55 1 2 3 4 »
  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. About Wolfgang Wieser

    Wolfgang Wieser

    Wolfgang Wieser is a Member of the BioMolecular Optics Group at the at the Ludwig Maximilian University of Munich.