Investigation of a four-wave mixing signal generated in fiber-delivered CARS microscopy

Jun, Chang Su; Kim, Byoung Yoon; Park, Jae Young; Lee, Jae Yong; Lee, Eun Seong

doi:10.1364/ao.49.003916

Cited by 9 publications

(5 citation statements)

References 14 publications

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“…The set-up is guiding pump and Stokes laser pulses in separate cores of a specially designed DCDC fiber for eliminating the non-phase matched FWM generation at the anti-Stokes wavelength in the delivery fiber of 1 m in length, which is typical for solid core fiber-delivery 15 , 16 , 18 , enabling small endoscopic heads without requiring excitation filtering 7 . Still, the solid DCDC fiber is efficiently guiding high-power pulses even at a small bending radius.…”

Section: Discussionmentioning

confidence: 99%

“…Alternatively, spectrally narrow lasers of low repetition rate and high peak power but ps duration efficiently reduce SPM, when using moderate peak power and limited delivery fiber lengths 5 . However, for fiber-delivered dual-wavelength lasers required for coherent Raman endoscopy, four-wave mixing (FWM) becomes the dominant background contribution within the delivery fiber 15 , 16 . The FWM background at the wavelength of the CARS signal can in principle be reduced by using delivery fibers of larger mode area 17 , using two separate fibers for the delivery of the two CARS-exciting laser beams 15 or removed after the delivery fiber by spectral filtering 7 , 18 .…”

Section: Introductionmentioning

confidence: 99%

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Multimodal nonlinear endomicroscopic imaging probe using a double-core double-clad fiber and focus-combining micro-optical concept

et al. 2021

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Multimodal non-linear microscopy combining coherent anti-Stokes Raman scattering, second harmonic generation, and two-photon excited fluorescence has proved to be a versatile and powerful tool enabling the label-free investigation of tissue structure, molecular composition, and correlation with function and disease status. For a routine medical application, the implementation of this approach into an in vivo imaging endoscope is required. However, this is a difficult task due to the requirements of a multicolour ultrashort laser delivery from a compact and robust laser source through a fiber with low losses and temporal synchronization, the efficient signal collection in epi-direction, the need for small-diameter but highly corrected endomicroobjectives of high numerical aperture and compact scanners. Here, we introduce an ultra-compact fiber-scanning endoscope platform for multimodal non-linear endomicroscopy in combination with a compact four-wave mixing based fiber laser. The heart of this fiber-scanning endoscope is an in-house custom-designed, single mode, double clad, double core pure silica fiber in combination with a 2.4 mm diameter NIR-dual-waveband corrected endomicroscopic objective of 0.55 numerical aperture and 180 µm field of view for non-linear imaging, allowing a background free, low-loss, high peak power laser delivery, and an efficient signal collection in backward direction. A linear diffractive optical grating overlays pump and Stokes laser foci across the full field of view, such that diffraction-limited performance is demonstrated for tissue imaging at one frame per second with sub-micron spatial resolution and at a high transmission of 65% from the laser to the specimen using a distal resonant fiber scanner.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Multimodal nonlinear endomicroscopic imaging probe using a double-core double-clad fiber and focus-combining micro-optical concept

et al. 2021

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“…One obstacle to deal with is four‐wave mixing (FWM) in optical fibers . When the pump and Stokes waves travel in the same fiber and are temporally overlapping, strong FWM signals are generated at ω FWM , which exactly matches the CARS frequency ( ω CARS = 2ω p – ω s ).…”

Section: Fiber Optic Probes For Coherent Anti‐stokes Raman Scatteringmentioning

confidence: 99%

Fiber optic probes for linear and nonlinear Raman applications – Current trends and future development

Latka

Dochow

Krafft

et al. 2013

Laser & Photonics Reviews

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This review focuses on fiber optic probes for linear and nonlinear Raman spectroscopy, especially for medical applications. It aims at providing an overview over contemporary technology, recent first clinical trials, and helps identifying future developments necessary to bring the emerging technology to clinical end users. After a short introduction to linear and nonlinear Raman spectroscopic modalities, general design considerations will be discussed and compared to common fiber probe setups. Subsequently, examples for medical applications of fiber optic Raman probes will be given concentrating on probes for linear Raman spectroscopy as these devices are technologically more mature compared to their counterparts based on nonlinear Raman spectroscopy. The review also includes a brief summary of first multimodal fiber optic probes and highlights their benefits for clinical applications. Finally, probes are introduced which employ either nonlinear Raman spectroscopy or surface enhanced spectroscopy.

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“…Shown in the Appendix, while the intensity of the FWM background from within the fiber varies greatly depending on which tip of the fiber the pulses overlap, the spectrum of the FWM background signal remains constant. The importance of the background FWM intensity as a function of delay overlap has been mentioned previously in several publications 9 , 12 , 20 …”

Section: Methodsmentioning

confidence: 68%

Intact primate brain tissue identification using a completely fibered coherent Raman spectroscopy system

et al. 2018

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Coherent Raman fiber probes have not yet found their way into the clinic despite their immense potential for label-free sensing and imaging. This is mainly due to the traditional bulky laser systems required to create the high peak power laser pulses needed for coherent Raman, as well as the complications that arise from the propagation of this type of energy through silica. Specifically, a coherent anti-Stokes Raman scattering (CARS) probe that could select its integration volume at high resolution, away from the tip of the fiber, is particularly interesting in the case of electrode implantation neurosurgeries, wherein it is possible to place optical fibers on-board the chronic electrode and provide optical guidance during its implantation, through the semi-transparent tip. To this clinical end, we have created an all fiber CARS system, consisting of small, rapidly tunable, turn-key fiber-lasers, capable of creating high wavenumber CARS spectra on the order of tens-of-milliseconds. The use of traditional silica fibers is made possible by the use of the laser's long pulse-widths (25 ps). The probe itself has an outer diameter of allowing it to fit within commercially available metal tubes that can replace deep brain stimulation (DBS) stylets. Using this system, we identified brain tissue types in intact nonhuman primates' brains and showed the ability to delineate white and gray matters with high resolution. Its advantages over spontaneous Raman stem from the orders of magnitude improvement in spatial resolution, its inherent translatability to three-dimensional (3-D) imaging, as well as the theoretical ability to remove parasitic Raman signal from probe encasements, such as a DBS electrode. The system is planned to have clinical implications in neurosurgical guidance as well as diseased tissue detection.

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Investigation of a four-wave mixing signal generated in fiber-delivered CARS microscopy

Cited by 9 publications

References 14 publications

Multimodal nonlinear endomicroscopic imaging probe using a double-core double-clad fiber and focus-combining micro-optical concept

Multimodal nonlinear endomicroscopic imaging probe using a double-core double-clad fiber and focus-combining micro-optical concept

Fiber optic probes for linear and nonlinear Raman applications – Current trends and future development

Intact primate brain tissue identification using a completely fibered coherent Raman spectroscopy system

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