Extended coherence length megahertz FDML and its application for anterior segment imaging

Wieser, Wolfgang; Klein, Thomas; Adler, Desmond C.; Trepanier, Francois; Eigenwillig, Christoph M.; Karpf, Sebastian; Schmitt, Joseph M.; Huber, Robert

doi:10.1364/boe.3.002647

Cited by 80 publications

(55 citation statements)

References 49 publications

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“…We believe that this is mainly due to the shorter intracavity delay fiber, which has reduced absorption and polarization rotation [60]. Second, intracavity chromatic dispersion was compensated by a chirped fiber Bragg grating (cFBG, Teraxion Inc.), which has been shown to greatly improve the coherence length of FDML lasers [48,61]. After the laser cavity, the fundamental laser repetition rate is increased by time-interleaving, a technique also known as buffering [62].…”

Section: Laser Setupmentioning

confidence: 99%

Multi-MHz retinal OCT

Klein

Wieser

Reznicek

et al. 2013

Biomed. Opt. Express

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199

124

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Abstract: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, long coherence lengths and 72 nm wavelength tuning range are achieved using a chirped fiber Bragg grating in a laser cavity at 419.1 kHz fundamental tuning rate. Very large data sets can be acquired with sustained data transfer from the data acquisition card to host computer memory, enabling high-quality averaging of many frames and of multiple aligned data sets. Three imaging modes are investigated: Alignment and averaging of 24 data sets at 1.68 MHz axial line rate, ultra-dense transverse sampling at 3.35 MHz line rate, and dual-beam imaging with two laser spots on the retina at an effective line rate of 6.7 MHz. 58. R. Huber, D. C. Adler, V. J. Srinivasan, and J. G. Fujimoto, "Fourier domain mode locking at 1050 nm for ultrahigh-speed optical coherence tomography of the human retina at 236,000 axial scans per second," Opt. Lett. ©2013 Optical Society of America

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Section: Laser Setupmentioning

confidence: 99%

Multi-MHz retinal OCT

Klein

Wieser

Reznicek

et al. 2013

Biomed. Opt. Express

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199

124

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“…213 However, due to the highly scattering nature of biological tissues and the contrast mechanism of OCT, which relies on the difference of tissue scattering properties, the penetration depth is limited to be within a few millimeters in most cases, even with the 1300-nm sources whose beam gets less scattered than the 800-nm sources. 4 For interconnected soft tissues whose scattering properties are similar, OCT's contrast is also hampered.…”

mentioning

confidence: 99%

Optical coherence tomography today: speed, contrast, and multimodality

Drexler¹,

Li²,

Kumar³

et al. 2014

J. Biomed. Opt

422

264

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Abstract. In the last 25 years, optical coherence tomography (OCT) has advanced to be one of the most innovative and most successful translational optical imaging techniques, achieving substantial economic impact as well as clinical acceptance. This is largely owing to the resolution improvements by a factor of 10 to the submicron regime and to the imaging speed increase by more than half a million times to more than 5 million A-scans per second, with the latter one accomplished by the state-of-the-art swept source laser technologies that are reviewed in this article. In addition, parallelization of OCT detection, such as line-field and full-field OCT, has shortened the acquisition time even further by establishing quasi-akinetic scanning. Besides the technical improvements, several functional and contrast-enhancing OCT applications have been investigated, among which the label-free angiography shows great potential for future studies. Finally, various multimodal imaging modalities with OCT incorporated are reviewed, in that these multimodal implementations can synergistically compensate for the fundamental limitations of OCT when it is used alone. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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“…Besides OCT, also non-destructive sensing and testing, optical molecular and functional imaging as well as short pulse generation have been shown with this laser [30][31][32][33][34][35][36][37]. In this work, the inherent low noise and good sweep-to-sweep correlation [38][39][40][41][42][43][44][45][46][47] are exploited to provide -in combination with a dual-balanced detection scheme -a fundamentally shot-noise limited detection sensitivity for SRS measurements. The FDML laser periodically and continuously tunes its wavelength over more than 150 nm around 1300 nm or 1550 nm with a repetition rate of 415 kHz at an average output power of up to 120 mW [48][49][50].…”

Section: Methodsmentioning

confidence: 99%

Hyperspectral stimulated Raman microscopy with two fiber laser sources

et al. 2015

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A fast all fiber based setup for stimulated Raman microscopy based on a rapidly wavelength swept cw-laser is presented. The applied Fourier domain mode locked (FDML) laser is a fiber ring laser, providing a continuously changing wavelength output over time. This fast swept source allows us to rapidly change the wavelength and, thereby the energy difference with respect to a single color pump laser. The pump laser is a master oscillator power amplifier based on a fiber amplified laser diode and a Raman shifter. By controlled variation of the relative timing between probe and pump laser with an arbitrary waveform generator, the Raman signals are encoded in time and they are directly acquired with a synchronized, fast analog-to-digital converter. This setup is capable of acquiring rapidly high resolution spectra (up to 0.5 cm -1 ) with shot noise limited sensitivity over a broadband (750 cm -1 to 3150 cm -1 ) spectral region. Here, we show the performance of this system for imaging in the CH-stretch region around 3000 cm -1 and in the fingerprint r egion around 1600 cm -1 . We present hyperspectral images of a plant stem slice with molecular contrast of lignin and a lipid representative as well as images of PS (polystyrene) and PMMA (poly(methyl methacrylate) beads with an acquisition speed of 18 µs per spectral point.

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Extended coherence length megahertz FDML and its application for anterior segment imaging

Cited by 80 publications

References 49 publications

Multi-MHz retinal OCT

Multi-MHz retinal OCT

Optical coherence tomography today: speed, contrast, and multimodality

Hyperspectral stimulated Raman microscopy with two fiber laser sources

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