1. Articles from Benjamin Biedermann

    1-8 of 8
    1. 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 ...

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    2. 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 ...

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    3. Wavelength-tunable light source

      Wavelength-tunable light source

      In at least one embodiment of the wavelength-tunable light source, it comprises an output source, which is capable in operation of generating electromagnetic radiation. Furthermore, the light source has a wavelength-selective first filter element, which is situated downstream from the output source. Moreover, the light source contains a first amplifier medium, which is situated downstream from the first filter element and is capable of at least partial amplification of the radiation emitted by the output source. The light source further comprises at least one wavelength-selective second filter element, which is situated downstream from the first amplifier medium, the second filter ...

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    4. 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 ...

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    5. Balance of physical effects causing stationary operation of Fourier domain mode-locked lasers

      Balance of physical effects causing stationary operation of Fourier domain mode-locked lasers

      We present a detailed analysis of the optical field dynamics in a Fourier domain mode-locked (FDML) laser. We employ a numerical simulation based on the FDML evolution equation, describing the propagation of the optical light field. The temporal evolution of the instantaneous power spectrum at different points in the laser cavity is investigated. The results are carefully validated against experimental data, yielding good agreement. Deeper insight is gained into the role of the physical effects governing FDML dynamics, such as gain recovery and linewidth enhancement in the semiconductor optical amplifier, dispersion and self-phase modulation in the optical fiber, and the ...

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    6. Instantaneous lineshape analysis of Fourier domain mode-locked lasers

      Instantaneous lineshape analysis of Fourier domain mode-locked lasers
      We present a theoretical and experimental analysis of the instantaneous lineshape of Fourier domain mode-locked (FDML) lasers, yielding good agreement. The simulations are performed employing a recently introduced model for FDML operation. Linewidths around 10 GHz are found, which is significantly below the sweep filter bandwidth. The effect of detuning between the sweep filter drive frequency and cavity roundtrip time is studied revealing features that cannot be resolved in the experiment, and shifting of the instantaneous power spectrum against the sweep filter center frequency is analyzed. We show that, in contrast to most other semiconductor based lasers, the instantaneous linewidth ...
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    7. FDML swept source at 1060 nm using a tapered amplifier

      FDML swept source at 1060 nm using a tapered amplifier

      We present a novel frequency-swept light source working at 1060nm that utilizes a tapered amplifier as gain medium. These devices feature significantly higher saturation power than conventional semiconductor optical amplifiers and can thus improve the limited output power of swept sources in this wavelength range. We demonstrate that a tapered amplifier can be integrated into a fiber-based swept source and allows for high-speed FDML operation. The developed light source operates at a sweep rate of 116kHz with an effective average output power in excess of 30mW. With a total sweep range of 70 nm an axial resolution of 15 µm ...

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    8. A theoretical description of Fourier domain mode locked lasers

      A theoretical description of Fourier domain mode locked lasers
      Abstract The first theoretical model of Fourier domain mode locking operation is presented. A specially tailored dynamic equation in a moving spectral reference frame is derived, enabling efficient numerical treatment, despite the broad laser spectrum and the extremely long cavity. The excellent agreement of the presented theory with experiment over a wide range of operation parameters enables a quantitative assessment of the relevant physical effects, such as the spectral loss modulation and gain saturation dynamics, amplified spontaneous emission, linewidth enhancement, and self-phase modulation.
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    1-8 of 8
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  2. Topics in the News

    1. (8 articles) Robert A. Huber
    2. (8 articles) Benjamin R. Biedermann
    3. (7 articles) Ludwig Maximilian University of Munich
    4. (5 articles) Wolfgang Wieser
    5. (4 articles) Thomas Klein
    6. (3 articles) Technical University of Denmark (DTU)
    7. (3 articles) Peter E. Andersen
    8. (3 articles) Sebastian Marschall
    9. (2 articles) Teresa Torzicky
    10. (2 articles) Erich Götzinger
    11. (2 articles) Medical University of Vienna
    12. (1 articles) Nara Medical University
    13. (1 articles) K. U. Leuven
    14. (1 articles) University of Alabama
    15. (1 articles) Singapore Eye Research Institute
    16. (1 articles) Michael Pircher
    17. (1 articles) Taishi Yonetsu
    18. (1 articles) Ursula Schmidt-Erfurth
    19. (1 articles) Tsunekazu Kakuta
    20. (1 articles) Dalip Singh Mehta
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    A theoretical description of Fourier domain mode locked lasers FDML swept source at 1060 nm using a tapered amplifier Instantaneous lineshape analysis of Fourier domain mode-locked lasers Balance of physical effects causing stationary operation of Fourier domain mode-locked lasers High-speed polarization-sensitive OCT at 1060 nm using a Fourier domain mode-locked swept source Wavelength-tunable light source Retinal polarization-sensitive optical coherence tomography at 1060 nm with 350 kHz A-scan rate using an Fourier domain mode locked laser Dynamical Fabry-Perot tuneable filter device High space-bandwidth in quantitative phase imaging using partially spatially coherent optical coherence microscopy and deep neural network Optical coherence tomography assessment of macrophages accumulation in non-ST-segment elevation acute coronary syndromes Early disability in ambulatory patients with multiple sclerosis: optical coherence tomography versus visual evoked potentials, a comparative study Dueling Deep Q-Network for Unsupervised Inter-frame Eye Movement Correction in Optical Coherence Tomography Volumes