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Fiber optical parametric oscillator for high-speed multicolor coherent Raman imaging (Conference Presentation)
Author(s): Maximilian Brinkmann; Tim Hellwig; Carsten Fallnich
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Paper Abstract

We present high-speed multicolor coherent Raman imaging (CRI) with rapid wavelength tuning within only 5 ms between successive images, enabled by a novel fiber optical parametric oscillator (FOPO). In CRI the limited tuning speed of conventional laser systems (at least several seconds per wavelength change) hinders the rapid acquisition of successive images at multiple vibrational frequencies and is a bottleneck for fast assessments of medical specimens or rapidly evolving samples. The output pulses of the presented FOPO are tunable across the vibrational spectrum between 865 and 3550 wavenumbers within only 5 ms. Therewith, the wavelength can be tuned in a frame-by-frame manner adequate for an image acquisition with up to 200 frames/s. Tuning of the FOPO is achieved by synchronized changes of both wavelength and repetition rate of the pump pulses, allowed by a novel fiber-integrated pump laser working without a mechanical delay. Based on this tuning mechanism, the FOPO resonator can be composed of all-spliced fiber components. Compared to previously presented FOPOs, the system exhibits short pulse durations of 7 ps and operates at a high repetition rate of 40 MHz to allow short pixel dwell times as low as 25 ns. The pump (>500 mW) and FOPO pulses (up to 200mW) exhibit equal durations and bandwidths below 12/cm. In comparison to previous approaches on multicolor CRI with multiple oscillators, requiring complex setups for synchronization, parallel laser amplifiers with limited emission bandwidth, or fragile mechanical delay lines, the realized FOPO system will dramatically simplify and improve CRI setups.

Paper Details

Date Published: 4 March 2019
Proc. SPIE 10890, Label-free Biomedical Imaging and Sensing (LBIS) 2019, 108900P (4 March 2019); doi: 10.1117/12.2509388
Show Author Affiliations
Maximilian Brinkmann, Westfälische Wilhelms-Univ. Münster (Germany)
Tim Hellwig, Westfälische Wilhelms-Univ. Münster (Germany)
Carsten Fallnich, Westfälische Wilhelms-Univ. Münster (Germany)

Published in SPIE Proceedings Vol. 10890:
Label-free Biomedical Imaging and Sensing (LBIS) 2019
Natan T. Shaked; Oliver Hayden, Editor(s)

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